| Reconfiguration sensing antenna (RSA) is a novel antenna concept, which not only can transmit or receive radio waves but also can sense the surrounding environment. The environment sensing is realized by reconfiguring the antenna's characteristics, such as resonant frequency, and radar cross section (RCS). The RSAs possess the advantages of passive and low cost, which make them suitable for the large-scale wireless sensing networks (WSNs) deployment. In this dissertation, the RSAs concept is demonstrated, and two sensing mechanisms performed in the RSAs are investigated. In order to verify these sensing mechanisms, four RSAs are designed, analyzed, and measured. All the RSA designs in this dissertation are temperature monitoring RSAs, and they realize the temperature sensing by reconfiguring the antenna resonant frequency.;About the two sensing mechanisms, one utilizes the electrical properties of materials, and the other utilizes thermal properties of the materials. For each sensing mechanism, there are two RSA designs using different sensing materials. As sensing antennas, sensitivity is a crucial factor in the RSA designs. Thus, a sensitivity evaluation method is also defined in this dissertation. There are three factors used to evaluate the RSA performance, which are Deltaf/DeltaT, realized gain, and realized gain bandwidth.;For the sensing mechanism using electrical properties of materials, water and high density polyethylene-Ba0.3Sr0.7TiO3 (HDPE-BST) are investigated and selected as the sensing materials. Patch antennas are properly designed to easily implement these sensing materials as their substrate. Simulation and measurement results show that these two designs provide 4MHz/10°C and 8MHz/10°C frequency shift with temperature, respectively. Their realized gain is -3.2dB with 4.33%. |
