Pre and Post COVID-19 Sentiment Analysis of Consumers for OTT Platforms

The entire media and entertainment industry are going through unprecedented changes in this age of digital disruption. The rise of the Over-The-Top (OTT) platform has transformed consumer experience and expectations. OTT players (Netflix, Amazon Prime Video, Hulu, Disney+, etc.) offer a wide array of diverse choices of content while enabling consumers to choose their content, watching time, and place independently. OTT platforms and digital media have already seen increasing popularity across locations and demographics. Adding to the momentum, due to the COVID-19 pandemic, social lives have shifted to online, people are restricted to their homes, so inclination towards OTT and digital media has accelerated significantly. Consumer behavior is undergoing profound change as the world adjusts to this new normal. This study aims to understand the changing consumer behavior towards the adaptation of the OTT platform during the COVID-19 pandemic.

Introduction
In recent times COVID-19 outbreak has resulted in significant economic, mental, and physical health consequences. Due to social distancing measures employed by several countries around the globe, the entire dynamic of how people communicate and work, how people live and interact with each other, how people move around, and travel has been changed. While adherence to these lockdown measures psychological traits like boredom, anxiety, stress, insecurities took a front seat for many of us. The COVID-19 pandemic is disrupting the way business functions. When comes to Entertainment and Media business, coronavirus creates both challenges and opportunities. Due to social distancing norms, home media consumption increased and big broadcasting events like live sports, theatre movie release have been postponed or cancelled. In response to all the difficulties, digital media has come up with some new normal aspects of the entertainment business. Global Media and entertainment have seen swift changes over the year. Digital disruptions have changed the way we experience content. With higher internet penetration and easy access to fresh content, the OTT industry has seen a drastic increase in revenue. OTT stands for "overthetop," which essentially means that audio-visual entertainment contents are delivered over the top of traditional types of TV receivers such as satellite, set-top boxes, and dishes to viewers by way of an on-demand delivery system (Urgelles, 2017). Some of the major Global players of OTT video platforms are HBO, YouTube Tv, Amazon, Hulu, Netflix, Apple, Crackle, Facebook watch, Sling, Disney, etc. India's first OTT video platform was BIGFlix by Reliance entertainment which was launched in 2008. Then Digivive launched the first OTT Video platform which could be accessed through a mobile phone called nexGTv which served both live TV and video on demand, in 2010. NexGTv was the first OTT video platform to live stream IPL in the years 2013 and 2014. In India, around 40 providers of over-the-top media services (OTT) are present in the market. PwC, Global Entertainment, and Media Outlook report 2019 suggested that the OTT Video market will grow almost double between 2019 to 2029 and will represent 72.8 billion industry by 2023 and will grow with almost 14% CAGR

Different business models for OTT Services
In this competitive age like any other industry OTT also revolved around different innovative business models that solely depend on the customer segment, market condition, and present competition. The following are the options present in the current market. • Subscription-based: Users need to pay a periodical (weekly/monthly or annual) fee to avail of the service. • Usage/Transaction: Users need to pay for a particular resource or service they are using. • Advertisements: Supplier sells their ads over the OTT platform while users are viewing any content over the OTT platform. • Freemium: This is a hybrid model where some basic content or features are free for any user, but some content or access is offered at a price. • Donations: There are some OTT platforms (Wikipedia), which are funded by donations.
• Monetization of Information: Users' data is disclosed, and suppliers monetize user information (Baldry et al., 2014).
Over the years significant changes had happened in different OTT platforms. Traditional telephone service is now facing a tough competition with OTT communication and SMS service replaced by different OTT players like Hike, WhatsApp, etc. Thus, traditional Telcom service provider is challenged in some of their business lines like long-distance calls, and SMS service. Also, the traditional media is facing huge competition by new OTT services providers for theircontemporary approach of audio and video streaming services. Today's consumers prefer "ondemand" experience. So, we can say there are a consumer preference shift from traditional entertainment & media to "on-demand" media. The rise of OTT platforms and the ease of access to mobiles have drastically transformed consumer preferences towards general entertainment provided by the traditional TV industry. According to a study by TechARCUnomer, 4 out of 5 smartphone users have at least one OTT entertainment platform which is 80% of whole smartphone subscribers (Khatri, 2019). In 2018 the OTT platform revenue in India was evaluated to be 638 million this was majorly due to driving digital media consumption on mobile devices and the evolution of smart TV which allows OTT platforms to broadcast on television via the use of WiFi. Both global and Indian OTT players are providing multiple choices around content consumption to the consumer, due to which consumer preference is shifting. Domestic OTT players like Hotstar have made disruptions to how consumers used to watch the sports content. According to figures released by ICC in 2019, the world cup semi-final between India and New Zealand made a record with 25.3 million people live streaming the match on Hotstar (Rashid, 2019). COVID-19 pandemic has restricted live entertainments and film business due to several social distancing laws and lockdown policies imposed by the government. Like many other countries In India government extended lockdown for more than 4 months resulted in a huge financial crisis in the film industries due to the inability to release movies within cinema halls. So, by following the classic rule "necessity is the mother of invention" this pandemic situation creates a brand-new way of a cinema release in OTT platforms. This move of many filmmakers resulting in prominent engagement of OTT media platforms in Movie release even after the removal of lockdown Policies. According to a report published by Reuters, Netflix's global total has reached 182.9 million from January to March (Richwine & Rana, 2020).It shows that people are bingeing on shows ISSN: 00333077 www.psychologyandeducation.net like Money Heist, Dark, Love, and Blind, etc. This pandemic had contributed significantly to the already changing behavioral patterns of consumer abut digital consumption.

Objective
The primary objective of this paper is to understand consumer perception about the OTT platform during the pre-COVID-19 phase and post COVID-19 phase and analyze current consumer engagement with popular OTT players, through sentiment analysis.

Literature Review
Over-The-Top service providers deliver video, audio, and other type of content over the internet and eliminate the traditional telecom operator's network. As OTT players do not need specific technology and business affiliations with telecom network operators, they are familiar with the term "Over-The-Top" (OTT) applications (Kokaram et al., 2015). According to Herrero, the distribution of audiovisual content over the Internet is a great way to realize economies of scale and effective broadcasting strategies. But the most difficult part for the telecom players is the fact that these OTT players offer services that are close substitutes to their offerings and are posing a significant threat to their revenues. The wide range of variety of services and applications offered by OTT players is tempting the customers away from the telecom players (Herrero-Subías, 2003). (Budzinski & Lindstädt-Dreusicke, 2018) mentioned three characteristics of the OTT platform in contrast with the traditional entertainment medium. Firstly, OTT significantly reduces the distribution costs and offer an open platform in which creators can share their content through an online medium (e.g. YouTube, Hotstar) and reach to a large number of audiences across demographics easily. Secondly, platforms like OTT successfully bridges the gap between the customer and content provider through real-time feedback (e.g. reviews, comments, likes, ratings). In this analytical age, feedback data plays an important role in an overall understanding of customer demand and delivering expected outcomes well. Lastly, OTT enhances the customer experience by making content available on various devices like mobile laptops, tablets, etc. Witnessing the outcome of a thirty-country study, (Noam, 2016) concluded that concentration levels for mobile wireless and other "network media" are "astonishingly high". While the data for content media is mixed, the trend of adopting OTT is increasing. A study conducted in India reveals that OTT platform is becoming popular day by day and youth prefer to watch the content of their own choice on OTT platform, because of its multifaced feature and flexibility and wide range of variety (P. Singh, 2019). So, entertainment trends are changing due to Online platforms. People are shifting from traditional channels to the OTT platform because of the more personalized experience and that increases the penetration of mobile computing devices. The mobile phone provides more convenience of watching preferred content at anytime and anywhere rather than smart TV, laptops, and other devices. We can say that OTT (over-the-top) platforms have challenged the Indian entertainment media. Subscription-based OTT platforms like Amazon Prime, Hotstar, NextG have become popular over the past years and replacing traditional Television media for progressive Indians (Kohli, 2019). Worldwide digital media is projected to increase to $118bn by 2021 with a compound annual growth rate of 11% between 2016 and 2021 (Lacy, 2017). A recent survey by InMobi states that in this COVID-19 situation 46% of consumers are preferring to watch content online. According to the study, OTT services could evolve drastically in upcoming days as the traditional television channels lack in terms of the latest content. In such an unprecedented time, people are stressed and willing to watch fresh content. To leverage the benefit from this increasing pattern of demand OTT platforms such as Zee5 and VOOT have offered few contents free. Due to this, Zee5 has achieved an 80% increase in subscription and over 50% time spend recently. Urban drama, thrillers, and young romance are the top-performing genres on the platform. The number of viewership for the movies has seen a significant increase over the last couple of months during the ongoing pandemic situation, across many OTT platforms. Movie streaming services MIBI has witnessed a 28% rise in viewership in March, compared to ISSN: 00333077 www.psychologyandeducation.net February. In the ongoing COVID-19 pandemic situation consumption of OTT platforms has increased and surprisingly despite the ongoing economic crisis subscription trend has not been affected (D. Singh, 2020). The first stage of the internet revolution was introducing a wireline environment. This facility of the web became available on laptops, PCs, and other electronic devices. Offering such as eCommerce, OTT Voice service came into the picture of modern life. The next stage of the internet revolution is wireless and is being driven by the domination of smartphones. Nowadays market boundaries are becoming a blur and new players are entering with innovative business models. Internet and OTT services allow these players to achieve benefits from economies of scale far beyond those of traditional telecom operators. This media market dynamism has the regulatory norms struggling to sustain in the competition space. One after another issue regarding regulation keeps coming up and the market is influenced by just in time principals (Baldry et al., 2014). This changing market dynamic indicated that Just like a coin has two sides, the OTT platform also has a flip side of it. Along with a high pace of market penetration OTT has to bring differences amongst family members as well as individuals or we can say generations. In the previous era family use to go out have fun and watch a long-awaited movie on the television or in a theatre. But nowadays, the same family would prefer ordering food online through some web application and watch some specific video content over internet applications. This phenomenon is mostly seen in the young population of the country, which has led to creating gaps amongst family members as many of the senior citizens often complain that their children or grandchildren do not spend enough time with them (Baldry et al., 2014). OTT Media has also underlined several data consumption issues. Most data plans have a limit on data usage, after the predefined limit volume tariff or limited data transmission speed applies. The above data points prove that despite the wide variety of content and becoming a close substitute to the traditional entertainment medium there are certain challenges attached to the OTT platform. Based on an analysis of how Netflix impacted television industry in Hong Kong shows that customer viewing habit is changing, and quality of content plays an important role while selecting the mode of entertainment beside this the study also suggest that people are interested in OTT video platform, but they hesitate to pay subscription fees (Madhani & Nakhate, 2020). So, there is a need to understand what exactly consumer is thinking about OTT platform and are they ready to adopt this latest entertainment media trend or not. Previously consumers use to rely on the other's opinions like specialized magazines and friends' recommendations and while making a buying decision. But along with the growth of digital technology and internet facilities, information sharing pattern has been shifted tremendously (Cambria et al., 2013) Nowadays consumer follows online rating app, blogs, social networks, forums, and contentsharing sites, etc to understand the effectiveness of a product or service. Many reports and researches suggested that nowadays using various social media platform is considered as the best way to grow a business(Edosomwan et al., 2011). These social platforms contain a huge amount of opinion about almost each and every possible product or service. But processing these data and drawing meaningful business insights is difficult, so here also technology has brought some advanced intelligent data analysis methods like sentiment analysis, natural language processing (NLP), etc , through which we can understand consumer expectation in a structured manner (Li & Wu, 2010). The literature reviews, provide insights about how the OTT platform is transforming the entertainment industry but still, there are some areas where some gaps exist in researches like understanding consumer mindset towards the adaption of On-demand-entertainment media in the pre-COVID-19 era and COVID-19 era. ISSN: 00333077 www.psychologyandeducation.net

Methodology
In this digital age usage of social media is growing rapidly and a good number of people share their opinions and experiences through these sites. By using one of the great engagement social platforms, Twitter, data was collected through web scraping and done sentiment analysis about the consumer mindset towards the OTT platform during this COVID-19 situation. Twitter is an American social networking and blogging service where users can post their opinion or tweets or communicate with other users, comment on other's tweets, use popular hashtags to reach out to a wider audience. Twitter is an informative social platform and has a constructive culture of discussion compared to other social media platforms. That is why twitter data was chosen for further analysis. Sentiment analysis is a method of data analysis that provides valuable insights about what people are thinking about a particular topic. Through sentiment analysis polarity classification and emotion classification of the people were done to understand what people are thinking about OTT platform adoption.
Tools Used Different programming languages (i.e. Python, R) platform (Anaconda-Jupitar notebook) and data analysis methods (sentiment analysis, polarity check, emotion classification) are used for the research purpose. Web scraping is used to fetch multiple tweets related to the OTT media platform. Web Scrapping is an automatic data collection method from the online platform. By using tweepy, python library, the twitter account was linked with the coding platform (Jupyter) and data is fetched in a data frame. Finally, fetched data saved in a csv format for further analysis. For sentiment analysis and data visualization R programming language is used. R programming is a very user-friendly programming language to perform any statistical analysis. In the R-studio packages like syuzhet, lubridate, ggplot2, scales, reshape2, dplyr have to be added for performing the statistical analysis.
Data collection This research paper is mainly based on secondary research, where the data has been collected from Twitter using a web scraping technique to understand the sentiment of people in the pre-COVID era and during the COVID-19 era regarding OTT platforms. For the research purpose, created a developer account in app.twitter.com to link the python platform (Jupyter Notebook) with the twitter account. At first, comparative sentiment analysis was done among pre-COVID 19 phase, Lockdown phase, and post Lockdown phase considering individual phase-wise dataset of 300 sample data each. For further analysis of the people's perception of OTT platforms through word cloud generation technique, 650 tweets were collected using relevant keywords (i.e. OTT, Netflix, Amazon prime video, VOD, SVOD, Voot, YouTube, Disney+, Hotstar) and hashtags(i.e. #ott, #bingewatch, #webseries) related to Over-The-Top media service. Identified the top 3 OTT players, by using the word cloud and collected three individual datasets for each of these players containing 200 sample data each.

Data Pre-Processing
Data Pre-processing or data cleaning is a necessary step in the analysis. That is why in the pre-processing only the body of the text of the tweets has been extracted from the entire file using the R-programming language. After that, in the data cleaning stage punctuation, numbers, URLs, stopwords, white space were removed since these are not required for the analysis.A small sample of data before data cleaning and after data cleaning is shown below. ISSN: 00333077 www.psychologyandeducation.net Consumer behaviour is important part for any business model and to understand the consumer behaviour and customer mindset sentiment analysis plays a very important role. Using sentiment analysis, understanding of what the customer thinking, whether they have positive or negative sentiment towards a particular product or service can be gained. In this paper word cloud, polarity classification and emotion classification are used for in dept sentiment analysis to draw insights about the consumer perception of OTT media platform and OTT players.

Measurement
The data generated from the data cleaning stage is the actual input for the sentiment analysis and the data were analyzed further through R programming.

Word Cloud Generation
Word cloud is a cluster of words where the most frequent word has a bigger size and with a decrease in frequency size of the words are also decreased. In the first step, the most frequently used terms in the data set were identified by text mining, while searching for the OTT platform using the term-document matrix. It helps us to find out keywords and important thoughts that come to the consumer mind while they heard about the OTT platform.

Polarity Checking
It is the measurement of whether the speaker expresses a positive or negative opinion. It is useful to check whether a statement is positive, negative, or neutral. The percentage of people inclined to a certain Polarity is plotted in a bargraph. Polarity value varies from -1 to +1 range. Where '+1' represents strong positivity,' O 'represents neutral, and '-1 'represents strong negativity. For the research purpose, the dataset(tweets) is categorized into 3 segments following the below described scale.
Polarity score Statement Sentiment > 0 Positive 0 Neutral < 0 Negative  Figure 3: Phase Wise Sentiment Analysis for OTT Platforms From the above bar graph, it is evident that during this COVID-19 pandemic people's engagement and people's opinion about the OTT platform has improved. According to the sentiment analysis result, during the lockdown period, positive engagement has increased 8% over the pre-COVID-19 phase which has declined again post lockdown. Still, It can be concluded that over the period of time and due to this ongoing pandemic more people are positively adopting different OTT mediums, as the pre-COVID-19 positive score was 53% and in recent times (post Lockdown) it is 55%. As mentioned, that more people are reacting positively about OTT platforms as an entertainment medium, emotion classification can help us to gaze people's reactions more precisely. In recent times overall people's sentiment can be understood better through this technique. Emotion classification is a very insightful tool of sentiment analysis helps us to understand consumer sentiment patterns attached to a particular topic. In this paper, consumer sentiment is classified into 10 different sentiment paraments like positive, negative, trust, surprise, sadness, joy, fear, disgust, anticipation, and anger. ISSN: 00333077 www.psychologyandeducation.net

Figure 4: Emotion Classification of Twitter Dataset
The above emotion classification of the OTT platform further clarifies that people are willing to adopt the OTT platform because the count of positive words is more than 550 whereas the count of negative words is much lesser than positive words. It also showcases that people are ready to trust the OTT platform because the count of trustworthy words is more than 300. Some fear is still attached to it, but consumers are more anticipated and have the joy to engage with the latest trend of entertainment media. Now for understanding what stuck consumer's minds, most when they think or asked about OTT platforms, the word cloud is generated through data mining. Using the term definition matrix most common and frequently used buzz word about the OTT platform was identified. TermDocumentMatrix is a matrix that helps find the frequencies of a particular term used. It is very important since it helps us to understand the most frequent word used by consumers. Better visual insight was inferred through the word cloud of the OTT platform shown below. Word Cloud represents a cluster of the most frequent words used along with the topic "OTT platform". The size of any word in the word cloud depends on the frequency of that particular word. So higher the frequency larger the size of the word and the lower the frequency smaller the size of the word.

Figure 5: Word Cloud of Dataset (OTT tweets)
It can be easily understood from the above word cloud of the 'OTT platform' that 'YouTube'  Limitations Technology and innovation are continuously shaping business models and accordingly consumer demand is also changing. Today a person can be satisfied with the current offering of a particular product or service, but it may happen that with changing time and market trend that person becomes dissatisfied with that product or service.

Managerial Implications
This study will be helpful to understand the consumer behavior towards the adaption of the OTT platform and customer inclination towards the current trend of entertainment. This research proves that consumers have a positive attitude about the OTT platform, and they are happy to adopt this on-demand entertainment model. This paper will surely motivate other researchers of the OTT platform or stakeholders who are working in this latest entertainment medium and definitely conclusion drawn from the research will be utilized for better customer satisfaction.

Conclusion
The current COVID-19 pandemic and different social distancing measured attached to COVID-19 has not only changed economic activity and industries but has also led to a change in behavioral patterns in consumers, including that of digital consumption. As the media and entertainment industry is heavily dependent on many on-ground events, huge losses and slowdown is observed in this sector due to COVID-19. But to the contrary OTT media has boomed as a sustainable alternative of traditional Entertainment and Media industry. The ongoing COVID-19 pandemic has added a whole new momentum to the digital revolution of the media industry. The subscription revenue, adaption rate of OTT platform is rising because of the quality content, flexibility, and variety. Another significant reason behind the increasing popularity of OTT platforms is the multiscreen availability of content and the high rate of smartphones/smart-devices penetration around the globe. Along with lucrative features, different innovative business strategies taken by different OTT players (i.e. free subscription, extended period offers, multiple viewership facility) could result in a new normal and indulge some permanent shift in the media consumption habit of consumers. More people are inclining toward the OTT platform during this lockdown period and the overall consumer mindset towards the OTT platform is showcasing significant positive responses.


An Exploration into the Influence of Higher Vocational Students’ Psychological Capital on Their Employability

. Cultivating higher vocational students’ employability is one of the most important goals for higher vocational education. Many researchers address teachers’ key roles in cultivation of employability. However, the cultivation of employability relates to students’ family environment and psychological capital. Through the collection of demographic data, 6700 higher vocational students were investigated with the Positive Psychological Capital Questionnaire (PPQ) and the College Students' Employability Questionnaire (CSEQ). The results show that psychological capital is significantly correlated with employability (P < 0.01); although family environment can not regulate the impact of psychological capital on employability, it works independently as psychological capital does; the self-efficacy, optimism and hope in psychological capital significantly affect the employability of higher vocational students from single-parent families. The improvement of psychological capital is conducive to the cultivation of employability of higher vocational students from single-parent families.

Introduction
In recent years, with the number of college graduates rising increasingly, the employment pressure of college students is growing rapidly [1]. The employment problem has become the focus of the government, universities and other relevant departments which need to be resolved. Employment is an important issue relevant to people's livelihood. Thus many scholars have discussed this issue from different perspectives and expected to find out the solutions. From the perspective of supply-side reform, some scholars suggested that colleges and universities should strive to improve the employability of college students, so as to help them obtain satisfactory employment results [2]; some scholars proposed from the perspective of government management and enterprise development that the government should take tax measures to reduce the burden of enterprises, so as to provide a good employment environment for college students [3]; some scholars believed that the government should focus on the reform of the supply-demand structure, actively adjust the professional settings of various colleges and universities, and resolve the contradiction between supply and demand in the employment market [4]. In sum, from the macro level, the supply-demand structure of employment market determines the quality of the employment situation; from the micro level, the evaluation of employment situation and the trade-off of employment result vary among different people, which depend on the individuals' internal cognition and value orientations toward employment results.
Because of the existence of inclination of benefit maximization and the orientations of social values, individuals can evaluate the employment results under the guidance of social values and the pursuits of their goals, thus the employment result itself has the social attributes and becomes an important indicator to reflect the qualities of individuals' employments. The employment result is a result of combination of multiple factors and levels. It is not only affected by the external employment market, but also relates to the college students' internal abilities, such as employability and so on. Some researches show that the employment result is affected by the internal factors such as individual's employability, professional images, personality traits and professional choices. Among them, employability is one of the most important factors affecting possible employment results. The qualities of individuals' employment results are directly relative with their employability [5]. Employability is the precondition for individuals to obtain employment opportunities and improve their job satisfactions. It is also an important core of workplace competitiveness. The improvement of college students' employability is helpful to solve employment problems, guarantee employment opportunities and obtain satisfactory employment results.
The way to improve the college students' employability has always been the focus of many scholars. The literatures about employability usually concentrated on the structure, measurement and antecedents of employability. For example, X. Gong and his colleagues (2018) divided the employability of college students into four dimensions: professional ability, quasi-professional image, personality compatibility and employment personality [6]; W. Cheng (2016) proposed a six-dimensional model of employability through interviews and factor analysis [7]; Y. Cui (2017) discovered a significant impact of psychological capital on employability by analyzing 289 medical students' employability [8].
According to previous researches, psychological capital is the general name of all the positive mentality states which is superior to human capital and social capital, it can help people obtain competitive advantages and improve their employability [9,10]. Individuals with higher psychological capital can obtain more psychological resources, their academic performances and interpersonal relationships are better than those who own lower psychology capital [11]. These essential factors are conducive to the improvement of employability.
The psychological capital is closely related to the individual's family growth environment, and the family environment has an important impact on the individual psychological capital. When individuals get more spiritual and material supports from their families, their psychological needs are better met leading to the growth of psychological capital, which is conducive to the development of employability. These kinds of individuals usually show strong resilience and stable psychological qualities in their careers; however, when people are in the single-parent or divorced family environment, their mental health levels are usually low [12], and their psychological capital is poor [13], which may negatively affect the development of employability. Theoretically, the single-parent family environment may be one of the most important variables among various demographic variables affecting employability.
In order to elaborate the impacts of family environment and psychological capital on higher vocational students' employability, this paper takes the operational definition of demographic variable of family environment as whether higher vocational students come from single-parent families or not, and conducts research on the group of higher vocational students. This paper proposes hypothesis 1: family environment and psychological capital significantly affect higher vocational students' employability. However, there are two modes of the influence of family environment and psychological capital on employability: one is that family environment and psychological capital independently affect employability, there is no interaction between them; the other is that family environment influences employment ability by regulating psychological capital, and there is interaction between them.
The traditional view is that family environment has a great influence on individual employability. Not only dose family environment affect employability directly, but also affects employability through other variables, such as psychological capital. However, there is another view that the influence of family environment on individual's ability is gradually weakened with the increase of individual's social experience, and the socialization process weakens the influence of original family on individual's ability development. With the increase of individual social experience, the development of employability will gradually get rid of the restriction of family environment, so there is no regulatory effect of family environment on employability. In order to find out if there is an intermediate mechanism between family environment and employability, this paper establishes control model and regulation model to verify these views.
In addition, due to the negative impact of family environment, higher vocational students from single-parent families tend to have inferiority complex, jealousy and other negative emotions, which are easy to hinder the developments of their employability. Therefore, in order to better help vocational students from single-parent families develop their employability, the paper sets up hypothesis 2 (Hypothesis 2: psychological capital and its dimensions have a significant impact on the employability of higher vocational students from single parent families). From the different dimensions of psychological capital, this paper provides useful suggestions about the cultivation of employment ability for higher vocational students from single parent families.

Positive psychological capital questionnaire (PPQ)
The Positive Psychological Capital Questionnaire was used to measure the psychological capital of higher vocational students. The questionnaire is a measurement tool developed by Zhang Kuo and his colleagues on the basis of Psychological Capital Questionnaire (PCQ) compiled by Luthans et al. (2010) [14]. The questionnaire has 26 items and 4 dimensions, which are self-efficacy, resilience, hope and optimism. Each item was evaluated by Likert scale. The subjects were asked to choose from "completely inconsistent" to "fully consistent" according to the actual situation. Each item was scored from 1 to 7. The overall Cronbach's alpha coefficient of the questionnaire is 0.90, and the Cronbach's alpha coefficient of each dimension is 0.75, 0.75, 0.90 and 0.80 respectively.

College students' employability questionnaire (CSEQ)
The employment ability of higher vocational students was measured by the College Students' Employability Questionnaire (CSEQ) compiled by W. Cheng. The questionnaire consists of 89 items, each item is scored by Likert scale ranged from 1 to 7. The scale is divided into six dimensions, which are general vocational skills, professional core quality, career development potential, professional personality, team quality and leadership quality [15]. Previous studies have shown that the questionnaire has good reliability and validity, the internal consistence reliability of each dimension is between 0.83 and 0.97, and the convergence validity is greater than 0.8 [16]. Based on the measured data, the Cronbach's alpha coefficient of the scale is 0.97.

Measurement process
The unified instruction was carried out in class. The professional staffs were required to carry out measurement in batches, at different times and in different places, ensured the anonymity of the subjects and strictly controlled the common method deviation included in the measurement process [17]. SPSS18.0 software was used to analyze the measured data. The research methods included Pearson correlation, Moderated Multiple Regression and Stepwise Regression.

The relationship between psychological capital and employability
The data of 6658 vocational students were analyzed by Pearson correlation analysis. The results show that there is a significant correlation between the total score of psychological capital and its dimensions, the correlation coefficient is between 0.495 and 0.866; the total score of psychological capital and its dimensions are significantly correlated with employability, the correlation coefficient is between 0.429 and 0.712, showing a positive correlation with high intensity.

The impacts of family environment and psychological capital on employability
It's possible that family environment and psychological capital affect employability in different ways, that is, family environment independently affects employability or affects it by adjusting psychological capital. When family environment and psychological capital affect employability independently, the control model is established; when family environment affects employability by adjusting psychological capital, the moderated model is established. In order to explore whether the regulatory effect of family environment exists or not, the Moderated Multiple Regression (MMR) equation is established by using the interaction term of family environment and psychological capital [18,19]. Please see the following figure 1.

Fig. 1. The Comparison of Control Model and Moderated Model.
As shown in table 2, the explanatory power of psychological capital to employability is 0.735, while the explanatory power of family environment to employability is 0.018, both reaching significant levels, which support hypothesis 1. However, the interaction between psychological capital and family environment upon employability was not significant, △F(1, 16654) = 0.050, p > 0.5. It shows that family environment can not regulate the effect of psychological capital upon employability, thus the moderated model is not established; but family environment and psychological capital affect employability independently, the control model is established. The control regression equation was y = 3.431x + 4.532z + 56.553. Among them, X is psychological capital, Z is family environment.

The influence of psychological capital on the employability of higher vocational students from single-parent families
Y.J. Wang believes that psychological capital has a significant impact on college students' employability [20]. However, this study does not focus on subjects' family environment. As mention before, family environment is the key variable leading to people's various employability, thus family environment must be considered in further analysis. We select 736 higher vocational students from single-parent families as the research subjects, and test the influence of psychological capital on the employability of vocational college students from single-parent families by Stepwise Regression method. The results show that psychological capital can still significantly affect the employability of vocational college students from single-parent families. After controlling the effect of each dimension of psychological capital, self-efficacy, hope and optimism can significantly affect employability, their standardized regression coefficients are 0.297, 0.461 and 0.152 respectively, reaching a significant level; however, resilience dimension cannot affect employability, which is different from previous research conclusions [20], which may be caused by different research subjects. Previous studies mainly focus on ordinary college students, but for higher vocational students from single-parent families, their resilience levels are likely to be different from the overall levels of college students. On the whole, the four dimensions of psychological capital explain 60.10% variation of employability, which show that the influence of psychological capital on the employability of vocational college students from single-parent families is significant.

The control model of family environment and psychological capital affecting vocational college students' employability
The research shows that the employability of higher vocational students from two-parent families is significantly better than that of higher vocational students from single-parent families, F (1, 16655) = 4.448, p < 0.05. As for higher vocational students, a good family environment is conducive to the improvement of employability, while the broken family relationship and the lack of family care are harmful for the development of employability. However, the influence of family environment on employability is limited, and it is not the only factor which determines the development of employability. Compared with psychological capital, family environment has less influence on employability; at the same time, the regulatory effect of family environment on higher vocational students' employability is not significant, which means that family environment can not enlarge or reduce the effect of psychological capital upon employability. This is inconsistent with the traditional view. The traditional view is that family environment has an important impact on the development of individual ability. As a result of the lack of family care and parental education, the individual growing up in a single-parent family is sensitive, suspicious, and has poor psychological qualities, which seriously restricts the development of comprehensive ability. However, the research shows that family environment and psychological capital are two separated variables that affect employability independently and there is no interaction between them, that is, the influence of psychological capital on individual employability cannot be enhanced by family environment. Family environment is a relatively stable external variable, and its impact on employability will gradually decline with the passage of time. Individuals can heal themselves in the process of socialization, use the cares and helps of peers to make up for the lack of family cares, and repair the negative impacts of the original families on themselves. Therefore, with the increase of people's social experience, their employability will eventually get rid of the constraints of family environment and continue to develop. The impact of family environment on individual employability is generally fixed and short-term, while the impact of psychological capital on individual employability is dynamic and long-term. Psychological capital is a controllable internal variable, which corresponds to the individual's positive attitude, optimistic and progressive personality. Therefore, compared with the family environment, psychological capital has greater impact on the development of individual employability.

Improving the psychological capital of higher vocational students from single-parent family is conducive to the cultivation of employability
Psychological capital plays an important role in the cultivation of employability of higher vocational students from single-parent families, its pure effect is 0.739. The stronger the individual's psychological capital is, the more active he is to engage in work and study, and constantly improve his comprehensive ability. On the contrary, individuals with weak psychological capital tend to treat work and study with negative attitudes, which are easy to fall into self denial and form a vicious circle [21]. Therefore, giving full play to the positive role of psychological capital is of great significance to personal study, employment and work.
The improvement of psychological capital is beneficial to the cultivation of higher vocational students' employability. Therefore, higher vocational colleges can not only cultivate the students' employability from the perspective of core skills and professional knowledge, but also comprehensively improve the employability of higher vocational students from the perspective of psychological capital. Specifically, it is necessary to carry out the special training of employability from three aspects, such as self-efficacy, hope and optimism. Self-efficacy refers to the individual's belief and effort to complete the challenging tasks. Individuals with high self-efficacy often exhibit full confidence against the tasks and difficulties, and these mental qualities make them concentrate on the tasks without interruptions; hope is that individuals can persevere and adjust to achieve goals; optimism refers to an individual's positive attribution to the present and future [22]. Vocational colleges can focus on the three dimensions, and integrate the cultivation of self-efficacy, willpower training and attribution training into psychological classroom and group activities. By the means of discovering and emphasizing students' own advantages, students' self-efficacy would be cultivated. They can learn to build up their confidences in spite of setbacks by not only accepting their weaknesses, but also learning to see their advantages in the difficult circumstances. This process would benefit their self-confidences and improve their adverse quotients; by the means of helping students set up the reasonable goals that can be achieved through hard work, students would experience the success of self-fulfillment and become more persistent in the challenges. This process would be helpful for students to enlarge their willpower resources; by the means of guiding students to form the favorable habits, students would acquire knowledge effectively and get rid of the constraints of willpower resources which minimize the effect of willpower; by the means of practicing attribution training in psychological class or in extracurricular activities, students would develop their optimisms toward studying and living while they attribute success to competence and attribute failure to effort, their hopefulness about future would be reinforced. In sum, there are many ways to enhance people's psychological capital, through the acquisition of reasonable beliefs, the form of good habits and attribution training in class or in extracurricular activities, higher vocational students' employability would be better fostered.


A small footprint printed cross-dipole antenna with wide impedance bandwidth and circular polarization

Received May 28, 2021 Revised Jul 19, 2021 Accepted Aug 4, 2021 Wideband circularly polarized (CP) cross-dipole antennas with flat, cavity and artificial magnetic conductor (AMC) reflectors are proposed. Each proposed antenna consists of a pair of driven dipoles, a pair of vacant-quarter printed rings, and a 50Ω coaxial probe. The boomerang shape has been adopted in the crossed-dipole. This shape makes the design more compact, so it can be a good candidate in the antenna array because of reducing the mutual coupling. All numerical simulation works have been done using the ANSYS electromagnetic (EM) software based on the finite element method (FEM) algorithm. The presented crossed-dipole with a cavity has the best performance compared to ones with conventional flat and AMC grounds. However, the crossed-dipole with the AMC ground is a low-profile structure. Thus, the paper investigates and discusses the results of the proposed strctures thoroughly. The obtained impedance bandwidth (IBW) is 42% (5.17.85 GHz) and the axial-ratio bandwidth (ARBW) is 7.72% (5.86-6.32 GHz) for the crossed-dipole with the conventional flat ground (i.e., reflector). Furthermore, the IBW and ARBW for the antenna with the cavity reflector are 50.37% (5.08-8.5 GHz) and 26.4% (5.72-7.46 GHz), respectively. The antenna with the AMC ground has the characterstics of the IBW and ARBW as 38.16% (5.36-7.89 GHz) and 15.16% (5.79-6.74 GHz), respectively. All structures are designed to operate for the C-band and wireless local area networks (WLAN) applications.

INTRODUCTION
The cross-dipole antenna (CDA) has attracted a lot of attention among researchers in the last decade owing to its capability to generate almost pure circular polarization at a wide range of frequencies. As known, antennas with circular polarization are in high demand since it can receive and transmit signals at any orientation in space. Thus, mobile wireless communications and satellite applications cannot indispensible of these types of antenna to guarantee a good connection between two wireless ends. Historically, the CDA was invented in the 1930s, following the invention from Brown which was the first CDA under the name of "turnstile antenna". After that, in 1940s, the "superturnstile" antenna was developed with a wider impedance bandwidth design compared with the previous ones [1], [2]. In the1960s, a new design of CDA used a single feed, where the CDA had arms with unequal lengths. This aids to balance the phase difference between the two components of electric fields to generate perfect circular polarization signals with an axial ratio close to 0 dB. In other words, the condition was that both dipoles had equal real part admittance but different input angle by 90° leading into generation of circular polarization [3]. In addition, in the 2010s, the CDA was fed with two separated ports, having 90°phase shift needed as a phase difference between the two ports, a process of generation of circular polarization signals [4].
The most important criteria in the CDA is the circularity of polarization because the circular polarization antennas are the solutions for prohibiting multipath effects and alleviating the polarization mismatch problems as known among the wireless communication community. Here, some examples for the use of the circular polarization antennas are recalled for the sake of integrity such as: navigation satellite system global position system (GPS), broadcasting services (BDS) and global navigation satellite systems (GNSS) [5]- [7], wireless local area network (WLAN) [8] and radio frequency identification (RFID) [9], [10], wireless personal area network [11] and worldwide interoperability (WiMax) for microwave access [12]. Therefore, the cross-dipole antennas are sophisticated for the present and future communication systems. Moreover, this type of antennas can generate isotropic, dual, omnidirectional radiation patterns with circular polarization capabilities. Also, the cross-dipole antenna is convenient for single and multiband as in [12], a wideband as well [13], and broadband operation as in [14].
In the recent years, different kinds of wide band CP have been designed and fabricated, utilizing many types of radiated structures [12]- [42]. For example, the CDA with dielectric resonant antennas were reported, covering a wide band of frequencies and being as a stair shape [15]; a rectangular CDA with two half split cylindrical dielectric waveguides, operating at the higher resonant order modes to increase the bandwidth and to enhance the circularity of polarization was proposed in [16]; exciting dual modes in the dielectric resonant antenna (DRA) by inserting a pair of L-shaped slots is found in the literature [14], providing a good circular polarization performance. Alternatively, antenna aperture backed to artificial magnetic conductors artificial magnetic conductors (AMCs) was proposed in [17] to improve the antenna performance and to reduce the overall size. As found in the literature and undoubtedly, antennas that can cover a wide range of frequencies with circular polarization characteristics are the CDA, thanks to its infrastructure, consisting of a pair of dipoles with 90 degree phase shift, in particular, the vacant-quarter ring as proposed in [18]. Hence, researchers made a lot of efforts in such type of antennas [18]- [38].
To make the antenna more usable, many modifications have been made to widen the circular polarization bandwidth using parasitic elements. The CDA was first designed in 2008 with strip-line transmission lines which had 15.6% axial ratio bandwidth ARBW in [18]. Baik et al. proposed in 2011 the same antenna design with open loop parasitic elements to enhance -10 dB the impedance bandwidth (IBW) and 3 dB ARBW in [19]. Subsequently, Feng et al. [20] have used a single parasitic cross-loop. A cross stripdipole with a pair of dipoles to get wide band CP in [21], the same author enhanced his design by adding four square-slot patches to provide the broadband CP [22]. Nguyen et al. [23] have used a dual cavity structure to widen the CP wideband. Ta and Park has used in [24] a single cavity and magneto-electric (ME), which has good influences on the 3 dB antenna reflection (AR). Coupled rotated dipoles is presented in [25]. Also, a simple single parasitic element with utilizing a bias circuit to turn on-off the parasitic elements is introduced in [26], [27]. Other types and shapes to design the main arms of cross-dipole antennas to widen the ARBW and IBW were reported in [28]- [39]. Tran and Park [28] have used the bowtie shape with two slot-made etched on the main arms to make come up with a structure radiating at dual frequencies with the IBW and 3 dB ARBW of 57% and 51%, respectively. In [19], the same shape in the previous reference, the author has utilized four parasitic patches where the results are seemingly enhanced to have the IBW of 47.73% and 3 dB ARBW of 42.8%. More enhancements have been obtained on the IBW and ARBW compared to the previous references mentioned above. The obtained IBW and the 3 dB ARBW were 93.1% and 90.9%, respectively. This extraordinary enhancement is owing to using the sequentially rotated feeding lines and unequal crossslots [29]. In addition, the trapezoidal bowtie CD antennas are presented in [31]. On the other hand, different shapes of radiating cross-dipole antenna arms have been reported as in [32] and are used with the elliptical shape, giving good results in front-to-back ratio (FBR), IBW and 3 dB ARBW when using the reflector cavity. Moreover, there are more different shapes are presented in [33]- [35]. The rectangular arm of the CDA, rectangular arms with extension in the other side of the substrate connected by via to decrease size of the antenna and four step rectangular patch with adding dielectric slab above the irregular ground plane (reflector) is also proposed. All of those antennas are designed for one aim which is to enhance the IBW and 3 dB ARBW.
Subsequently, the artificial magnetic conductor AMC is presented in the literature with the crossdipole antennas to reduce the height which is equal to a quarter wavelength in conventional CDA. Using the AMC operates to alleviate the need to add this space between dipole's arms and the ground to make the interference between signal radiating from the dipole's arms and bouncing from the ground constructive. Then, the AMC has in-phase reflection, leading into adding the arms and ground adjacently. Additionally, the AMC gives new resonant frequencies, improving the impedance bandwidth [36]- [38]. The radiation arms were rectangular-shaped with parasitic strips to get a broadband AR where the two cross-asymmetric dual arms are used to radiate dual-band associated with T-shape slits etched on the unit cell patch of AMC structure. Most AMC structures use vias (pins) to connect the top conductor with the ground, but there is not few works using the AMC without vias.
In this paper, we propose a new design of the printed cross-dipole antenna with new shapes called boomerang shapes for sub-5G applications. The proposed antenna has a very good impedance bandwidth and an acceptable 3 dB ARBW that are extremely useful for antenna arrays. Section 2 presents the process of the proposed antenna design. In section 3, the main keys of the antenna design is introduced. Finally, section 4 concludes this research paper.

ANTENNA DESIGN 2.1. Antenna configuration and antenna operation
The cross-dipole structure is adopted here in this research study because of its advantage as mentioned in the previous section. The classic shape in [18] was presented in many research efforts. Recently, a wideband CDA can be gotten after many modifying the main arms or by adding parasitic elements close to the main radiators to produce several resonance frequencies [19]- [22], [24]- [27], [29]- [31]. Here, the boomerang shapes to design dipole arms are employed. As will be seen later, the boomerang arms aid to make the structure resonating at several frequencies and leading into a wideband structure compared to other designs [28]- [35].
As depicted in Figure 1 and Table 1, the antenna is a pair of boomerang arms connected together by the feeding network as driven elements. The feeding network consists of a pair of vacant quarter rings [18]- [39], and they are used to connect the two cross boomerang arms with 4 ⁄ length ( is the guided wavelength at the design frequency). Each side of the substrate has a single vacant quarter ring printed on its faces. The substrate used in the design has 0.5 mm thickness where its type is FR4 ( is 4.4 with loss tangent of 0.02). The semi-rigid coaxial cable of 50 Ω allows a 180° phase different between the two arms of each dipole. The inner conductor of the SMA is connected to the top arm and the outer conductor is connected to the bottom arm. The ground plane is placed on height H of 0.25 0 ( 0 : free space wavelength at 6 GHz) from the main radiator. The ground is a square shape and its side length Lr is equal to 0.785 0 , in which this size is optimized to mitigate the ground effects on the antenna performance, and keeping the overall size is acceptable. Table 1 summarizes the antenna dimensions.  There are two equal input admittances for both arms of the two cross dipole antennas with a 90° phase shift difference to obtain the CP associated by coaxial cables and the phase sequence on the four arms will be (0°. 90°, 180° 270°). The -10 dB IBW is 2.24 GHz with a center frequency of 6.38 GHz and 3 dB ARBW is 0.63 GHz with a center frequency of 5.9 GHz. Moreover, the most important property is the craving shape that introduces 25% length reduction than all the other CDA shapes. This reduction form is very useful in antenna arrays to increase space between antennas which in turn reduces the mutual coupling and increase the antenna efficiency.
In general, the proposed antenna type-I offers good results. However, this antenna does not fulfill our goals in this research. Enhancing the performance while keeping or reducing the size is an outstanding key. The research is committed to do so. The first way is to employ a cavity with four side walls. Walls prohibit signals to spread in a wider space, so the resulting radiation beam becomes narrower and the gain becomes larger. This antenna is type-II as shown in Figure 2(a). It produces more consistent pattern and greater gain with a comparison to traditional reflector patterns [23]. The second enhancement is the use of an artificial magnetic conductor AMC, called antenna type-III, as depicted in Figure 2 Cavity walls have height of 11.25 mm which is about 0.225 0 at 6 GHz and the same reflector widths of the antenna type-I. These four walls are made of conducting materials. In order to use an alternative way but keeping the same antenna behavior when using bulky cavities is to use a 2D sheet of the AMC surface operating as a reflector. The resulting antenna is type-III, displayed in Figure 2(b). the AMC surface consists of 7×7 unit-cells, printed on the top side of the lower substrate, with a thickness of 0.708 mm where the martial type is Rogers RT/duroid 6010/6010LM (tm) (εr=10.2 and tanδ=0.0023). Each unit-cell has a side length of Wc=6 mm about 0.12 0 , the spacing between the cells is Ws=0.5 mm and the edge spacing is We=0.25 mm then the overall reflector size is 46×46 mm 2 . The AMC reflector is placed with a height of HAMC=6 mm about 0.12 0 less by 50% than the antenna Type-I and type-II in the vertical dimension. This is one of the aims to use the AMC surfaces (i.e., to make a small microstrip antenna) [39], as shown in Figure 3.

Antenna mechanism
The evolution of all proposed antennas presented here is demonstrated precedingly to show up the mechanism for improving bandwidths. The first two enhanced antennas with boomerang arms types-I and II use the cavity to stop or at least to highly mitigate the backward radiation, especially a cavity with side walls, while the proposed antenna type-III is the CDA boomerang type with an AMC reflector. The antenna type-III has good reflection coefficient compared to ones in [18]- [27]. It is a good alternative to other arm shapes like bowtie CDA which have a wide impedance bandwidth as known compared to other shapes of the CDA [28]- [39], see Table 2 that summarizes the comparison between the proposed antennas and preceding works in the literature.

DISCUSSION OF THE RESULTS
To analyze and evaluate the performance of the proposed antennas a high frequency structure simulator (HFSS) software from ANSYS Company was utilized. The HFSS relies on the finite element method FEM algorithm to analyze designs. As the electrical size of a structure increases, its time evaluation becomes larger and burden. The first step in the design is to make the antenna having good matching at the design frequency. A mechanism of the impedance matching is qualitatively, where the equivalent circuit model of the antenna is provided in Figure 4. The symbol characterizes the total input admittance of the proposed antennas, means the antenna without the interlaced rectangular patches, whereas 1 and 2 mean the parallel-plate capacitors as seen in Figure 5. The capacitance of parallel-plate capacitors 1 and 2 can be considered when the density of electrical charge on the plates is uniform, and neglect the fringing fields at the edges. From Figure 5, the input admittance of the proposed antennas can be indicated by (1).
The approximation is derived from the small slot on the rectangular bottom patch that reduces the overlapping area of the condensers of the two parallel plates. It is shown in (1) that the rectangular patch width W and length L1 define the antenna input admittance Yin. Therefore, these two parameters can be tuned to the impedance characteristic of the antenna to achieve a good impedance. The simulated |S11| -10 dB IBW and 3 db-AR results of the antenna type-I are presented in Figure  6(a). Firstly, as can be seen, we see the wideband impedance bandwidth of this antenna and also have an acceptable CPBW without loading any parasitic elements or doing any enhancement. It was about -10 dB IBW of 42.47% (5.1-7.85 GHz) and the 3 dB ARBW of 7.72% (5.85-6.32 GHz). In addition to that, the simulated gain was about 7.4 dBi with efficiency of 97.37%, and the overall size is about (0.78×0.78 ×0.27 0 ).
Then, the CDA with square-box cavity is analyzed where the back-lobe radiation is highly attenuated. In other words, this structure can offer better back-lobe reduction compared to the CDA that has only sheet reflector (i.e., flat ground plane). This increase in the efficiency is primarily due to surface wave suppression and the blocking of diffracted waves along the edge of the ground plane, so, the antenna type-II introduces very good results with wideband impedance bandwidth where the -10 dB IBW of 50.37% (5.08-8.5 GHz) and the 3 dB ARBW of 26.4% (5.72-7.46 GHz), as shown in Figure 6(b). The simulated gain was about 8.3dBi with efficiency of 97.65%. there is no change in the overall size.
Finally, the proposed antenna type-III is studied numerically to obtain its results. Before integrating the conventional CDA into the AMC, we should analyze and check the performance of the AMC layer. To do so, a single unit-cell is placed in a cavity structure to mimic its periodicity. This method aids to decrease the solution time and offers results close to the original structure. The AMC unit-cell can be modeled as an identical parallel resonator with a resonant frequency of f =1/(2π(LC)1/2), here C and L represent equivalent capacitance and inductance, respectively. The range of acceptable phases offered by the AMC is from -90° to 90° [36]. Figure 7 shows the reflection phase of the AMC structure. For further analysis of the parameter effect on the reflection coefficient phase, complete numerical analysis of the AMC cell has been conducted by simulation software HFSS. As can be seen, this phase range can cover a wideband of frequencies.
The overall 38.19% (5.36-7.89 GHz) and the 3 dB ARBW is about 15.16% (5.79-6.74GHz). The vertical size was reduced to half, thanks to the use of the AMC layer. It is clear that the IBW less than the IBW of the Antenna type-I due to the use of the AMC substrate martial. Generally, the AMC layer considers lossy type type because of its high permittivity but we can obviously see the enhancement in CPAR bandwidth, as shown in Figure 8.  Figure 9 shows the simulated radiation patterns at 6 GHz in xoz-plane and yoz-planes. The patterns in xoz-plane are symmetrical to those in yoz-plane. The antenna generates unidirectional CP patterns in a boresight direction. The right-hand circular polarization (RHCP) is higher than the left-hand circular polarization (LHCP), generating exceptional RHCP radiation. characteristics with an impedance bandwidth (IBW) of 50.37% (5.08-8.5 GHz) and axial-ratio bandwidth (ARBW) of 26.4% (5.72-6.46 GHz) for cavity reflector. This antenna gave a good IBW and and gave the less length arm comparing with all others proposed CDA. So, the antenna has been more compact, this merit it will be very useful in array antenna by reducing mutual coupling and increasing the gain in antenna arrays.