Software controlled beam steerable antenna

• Main Author: Goonesinghe, Chandana Hasanga
• Other Authors: Mehta, Amit
• Published: Swansea University 2018
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752395

In this thesis I have presented a software controlled conformal beam steerable antenna for body wearable applications. The antenna is a square loop antenna conformal to a hemispherical shell. It generates 4 identical tilted beam patterns with high Directivity (9.2dBi). It has 4 RF ports which are connected to a RF switch which conducts the beam switching based on the electronic voltages it receives from a control circuit. By switching one port at a time, while keeping the remaining 3 ports open, it is able to steer the beam covering the full 360° azimuth range. An intelligent ’scan, analyse, lock and monitor’ algorithm has been used to lock the antenna beam to the direction of the strongest signal. This algorithm runs on a portable hardware platform connected to the RF switch. The thesis findings cover a study on the conformal nature of this square loop antenna on a variety of doubly curved surfaces. Its limits on bending are reported. It then reports the results of two experimental studies conducted to test the robustness of the beam switching algorithm. The first experiment involves using the antenna as a Base Station antenna which directs its beam towards a roaming mobile user based on the feedback it receives from the user. The second experiment involves using the antenna as a mobile user while the Base Station antenna is fixed. The algorithm switches ON the antenna’s 4 ports, one at a time, and then locks it to the port with the highest received signal strength. It was experimentally proven that in a weak EM environment where the received signal strength is close to the noise floor, the antenna running the beam switching algorithm was able to maintain high throughput in a HD video call conferencing application while conventional methods failed.