Understanding antennas for radar, communications, and avionics
Understanding antennas for radar, communications, and avionics
Proceedings of the 11th international conference on Information Processing in Sensor Networks
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A new technology breakthrough which allows any standard Bluetooth mobile phone to access information services using the same selective and deliberate gesture envisioned for NFC. This technology is called Bluetooth Touchpoint, and it consists of reconfigurable coverage that combines NFC-like, close-proximity communications with the long-range, roaming solution of today's Bluetooth devices. Phase shifting technology combined with a unique antenna configuration makes this realization possible. Therefore, as the world moves toward contactless, wireless communication links, it is believed that the near ubiquity of Bluetooth in mobile devices makes this technology an excellent choice for delivering the benefits of NFC today without the wait, effort and cost associated with adopting NFC globally. The main technology contribution is a new Bluetooth antenna design. This device is shown in Fig. 1. Instead of a single antenna, an array of antennas is integrated into the radio module. By carefully choosing the phase of radio signals sent at each antenna, constructive interference is created in certain special regions and cancel out the signals in other regions. Combining directionality with power control, the same antenna can be used to achieve three kinds of selectivity in device pairing, tapping, pointing, and approaching. Each is briefly explained below. Tapping - With tapping, the user explicitly place one device against another to make the connection. The key advantage of tapping is the deliberateness. The user knows explicitly which counterpart she is interacting with. Examples include tapping a phone at a sales terminal for payment and scanning a bar code for object identification. Pointing - In this mode of operation, the user points remotely to another device. The experience is best captured by remote control of home appliances. Unlike tapping, the users enjoy a better flexibility and range of the interaction range, without losing the deliberateness. Approaching - Two devices can be paired as long as they are in the proximity of each other. This mode gives users the best mobility as long as it is within the communication range of another device. However, it also loses deliberateness. When multiple target devices are in the same space, users typically need to resolve them manually. For example, with WiFi links, a mobile device can see multiple access points, and the user must select which one to use.