The present invention relates to a wave antenna coupled to a wireless communication device so that the wireless communication device can wirelessly communicate information.
Wireless communication devices are commonly used today to wirelessly communicate information about goods. For example, transponders may be attached to goods during their manufacture, transport and/or distribution to provide information, such as the good""s identification number, expiration date, date of manufacture or xe2x80x9cborn onxe2x80x9d date, lot number, and the like. The transponder allows this information to be obtained unobtrusively using wireless communication without slowing down the manufacturing, transportation, and/or distribution process.
Some goods involve environmental factors that are critical to their manufacture and/or intended operation. An example of such a good is a vehicle tire. It may be desirable to place a wireless communication device in a tire so that information regarding the tire, such as a tire""s identification, pressure, temperature, and other environmental information, can be wirelessly communicated to an interrogation reader during the tire""s manufacture and/or use.
Tire pressure monitoring may be particularly important since the pressure in a tire governs its proper operation and safety in use. For example, too little pressure in a tire during its use can cause a tire to be damaged by the weight of a vehicle supported by the tire. Too much pressure can cause a tire to rupture. Tire pressure must be tested during the manufacturing process to ensure that the tire meets intended design specifications. The tire pressure should also be within a certain pressure limits during use in order to avoid dangerous conditions. Knowledge of the tire pressure during the operation of a vehicle can be used to inform an operator and/or vehicle system that a tire has a dangerous pressure condition. The vehicle may indicate a pressure condition by generating an alarm or warning signal to the operator of the vehicle.
During the manufacturing process of a tire, the rubber material comprising the vehicle tire is violently stretched during its manufacture before taking final shape. Wireless communication devices placed inside tires during their manufacture must be able to withstand this stretching and compression and still be able to operate properly after the completion of the tire""s manufacture. Since wireless communication devices are typically radio-frequency communication devices, an antenna must be coupled to the wireless communication device for communication. This antenna and wireless communication device combination may be placed in the inside of the tire along its inner wall or inside the rubber of tire for example. This results in stretching and compression of the wireless communication device and antenna whenever the tire is stretched and compressed. Often, the antenna is stretched and subsequently damaged or broken thereby either disconnecting the wireless communication device from an antenna or changing the length of the antenna, which changes the operating frequency of the antenna. In either case, the wireless communication device may be unable to communicate properly when the antenna is damaged or broken.
Therefore, an object of the present invention is to provide an antenna for a wireless communication device that can withstand a force, such as stretching or compression, and not be susceptible to damage or a break. In this manner, a high level of operability can be achieved with wireless communication devices coupled to antennas for applications where a force is placed on the antenna.
The present invention relates to a wave antenna that is coupled to a wireless communication device, such as a transponder, to wirelessly communicate information. The wave antenna is formed through a series of alternating bends in a substantially straight conductor, such as a wire, to form at least two different sections wherein at least one section of the conductor is bent at an angle of less than 180 degrees with respect to the other. A wave antenna is capable of stretching when subjected to a force without being damaged. A wave antenna can also provide improved impedance matching capability between the antenna and a wireless communication device because of the reactive interaction between different sections of the antenna conductor. In general, varying the characteristics of the conductor wire of the wave antenna, such as diameter, the angle of the bends, the lengths of the sections formed by the bends, and the type of conductor wire, will modify the cross coupling and, hence, the impedance of the wave antenna.
In a first wave antenna embodiment, a wireless communication device is coupled to a single conductor wave antenna to form a monopole wave antenna.
In a second wave antenna embodiment, a wireless communication device is coupled to two conductor wave antennas to form a dipole wave antenna.
In a third wave antenna embodiment, a dipole wave antenna is comprised out of conductors having different sections having different lengths. The first section is coupled to the wireless communication device and forms a first antenna having a first operating frequency. The second section is coupled to the first section and forms a second antenna having a second operating frequency. The wireless communication device is capable of communicating at each of these two frequencies formed by the first antenna and the second antenna.
In a fourth wave antenna embodiment, a resonating conductor is additionally coupled to the wireless communication device to provide a second antenna operating at a second operating frequency. The resonating ring may also act as a stress relief for force placed on the wave antenna so that such force is not placed on the wireless communication device.
In another embodiment, the wireless communication device is coupled to a wave antenna and is placed inside a tire so that information can be wirelessly communicated from the tire to an interrogation reader. The wave antenna is capable of stretching and compressing, without being damged, as the tire is stretched and compressed during its manufacture and pressurization during use on a vehicle.
In another embodiment, the interrogation reader determines the pressure inside a tire by the response from a wireless communication device coupled to a wave antenna placed inside the tire. When the tire and, therefore, the wave antenna stretch to a certain length indicative that the tire is at a certain threshold pressure, the length of the antenna will be at the operating frequency of the interrogation reader so that the wireless communication device is capable of responding to the interrogation reader.
In another embodiment, a method of manufacture is disclosed on one method of manufacturing the wave antenna out of a straight conductor and attaching wireless communication devices to the wave antenna. The uncut string of wireless communication devices and wave antennas form one continuous strip that can be wound on a reel and later unwound, cut and applied to a good, object, or article of manufacture.
Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures.