Compact electronic equipment is required to be compact in size, especially when portable. Therefore all components incorporated in portable electronic radio equipment have to fulfill this requirement. Furthermore the spatial arrangement of the components of the portable electronic radio equipment has to be as compact as possible due to the above requirement. Also, the components should not interfere with each other. As more features are integrated in portable electronic radio equipment, such as cameras, the requirement of minimal size is harder to fulfill. Therefore a need exists to find new ways of assembling the components of portable electronic radio equipment.
The term portable electronic radio equipment, which hereinafter is referred to as a mobile radio terminal, includes all equipment such as mobile telephones, pagers, communicators, i.e. electronic organisers, smartphones or the like, PDAs (Personal Digital Assistants), portable communication apparatus etc.
Traditionally, older mobile radio terminals were only capable of normal speech communication between two users through a mobile communications network or a public switched telephone network. Historically, mobile radio terminals often have an antenna mounted externally to the housing of the mobile radio terminal. More recently, mobile radio terminals have built-in antennas.
Even more recently, short-range supplementary communication services have been introduced for mobile radio terminals. One example of such a short-range supplementary communication service is commonly referred to as Bluetooth® and operates within an unlicensed frequency band at 2.4 GHz, which is often referred to as ISM (“Instrumental, Scientific and Medical”) and is globally available. Bluetooth® is intended to provide flexible communication of data and speech between portable devices, such as mobile telephones, mobile computers, other handheld devices and various peripherals for these devices, such as printers, wireless headset accessories, etc.
Furthermore, Wireless Local Area Network (W-LAN) solutions provide extended reach of hard-wired Local Area Networks (LANs) allowing to connect e.g. to the Internet or a corporate network. Wireless LAN access zones are even being installed at public places such as conference areas, hotels, airports and railway stations offering users wireless connection to networks. Future mobile radio terminals will support W-LAN technology. W-LAN is currently based on 2.4 GHz technology, but future products will even support frequencies of 5.8 GHz or above for enhanced performance.
Moreover, mobile radio terminals with built-in cameras have been introduced. These mobile radio terminals comprise a camera unit with a camera lens assembly. The mobile radio terminals equipped with said camera units offer the possibility of image communication. The image communication can take place in several ways, such as via the above described wireless Bluetooth® communication for direct printing of the captured pictures or films, or transmission to other units such as other mobile radio terminals or mobile computers. Another way of transmitting the images is via the above described W-LAN directly to a network, such as an enterprise network, and directly accessing all available network resources, such as network printers, networked computers etc. Even another way of transmitting the images is by using a transmission via the above mentioned mobile communications network or public switched telephone network. All transmissions have in common that they are performed electromagnetically wireless and therefore need an antenna for communicating.
A mobile radio terminal for image communication with an integrated camera lens assembly is known from KR-A-2001059498. According to FIG. 3, a mobile radio terminal 20 is described therein and has an antenna 201 inside a cover 202 extending on the upper side of the housing 200. A camera lens assembly 203 is installed beside an ear piece 204 and a display 205. As mentioned above, it is desired to have such an antenna integrated in or built-in within the housing of the mobile device in order to render the mobile radio terminal more compact.
US-B1-6 327 484 describes a cellular telephone having an integrated laser pointer. The laser pointer is built into an antenna assembly arranged externally on the housing of the cellular telephone. Furthermore the laser pointer assembly comprises an optical lens through which a substantially coherent beam of visible light is emitted from a laser diode and transmitted away from the cellular phone to a remote point that is to be highlighted by the laser beam of the laser pointer. However, the lens is not adapted to be used as a camera lens. The optical lens disclosed is rather adapted to focus and concentrate a beam of light from the inside of the telephone to the outside of the telephone to a remote location. Furthermore the antenna of the laser pointer assembly is not arranged in a space-saving manner.
JP 2001 104241 discloses an endoscopic capsule having an integrated image sensor and an antenna for radio transmitting electric signals outputted from the image sensor. A transmitting antenna for transmitting the signal is wound around the periphery of an electric component holding tube comprising electronic circuits and batteries for the capsule.
U.S. Pat. No. 5,666,159 discloses an electronic camera system for selectively transmitting electronic image data to a plurality of remote base units. A camera module is detachably coupled to a portable computer. The electronic image data generated by the camera module is supplied through the portable computer and therefrom to a radio frequency transmitter module for transmission to the selected base unit. The radio frequency transmitter module is either formed integral with the portable computer or like the camera module, it is detachably coupled to the portable computer. The camera module is always separated from the transmitter module. The disclosed device is not space saving.
As mobile radio terminals on one hand become smaller and on the other hand more features, such as the above mentioned camera function, are integrated into the mobile radio terminal, various problems are associated with the conventional way of arranging antennas inside conventional mobile radio terminals.
One problem is that an antenna, if integrated in the housing of the mobile radio terminal, as desired, consumes valuable space and renders the mobile radio terminal larger than desired.
Another problem is possible hand interference of the user's hand with the electromagnetic field of the antenna. This problem can arise if the antenna is so arranged that the hand of the user holding the mobile device disturbs the field of the antenna, due to ergonomic arrangements too near to the antenna. Cellular radio circuitry is prioritised in the layout of the printed circuit board, and as a result, in existing mobile radio terminals, the built-in antennas were placed in areas where the performance of the antenna was disturbed by the hand of the user.
A further problem arises if the mobile radio terminal is equipped with multiple antennas, e.g. working in different frequency ranges, because the antennas can disturb each other if they are positioned too close to each other. In order to avoid this interference, expensive filtering components have to be provided for isolating the antennas from each other.
Furthermore, low loss of the antenna is desired. When integrating antennas in the housing, the housing can absorb transmission energy, which is not desired.