UCLA

Radio frequency identification (RFID) technology in the ultra-high frequency (UHF) band has become the mainstream applications that help the speed of handling manufactured goods and materials in recent years. The mechanism of RFID backscattering technique has also been utilized for many novel wireless sensing applications, such as remote health sensing, and biomedical signal recoding. In an RFID system, the tag antenna plays a key role in the overall system performance. In this sense, the study of novel tag antenna design with compact size and circular polarization (CP) characteristics is necessary to achieve miniature and highly-sensitive RFID systems. In the first part of the thesis, we present a CP cross-dipole RFID tag antenna with miniature design. The CP mode is excited by two orthogonal dipoles with 90 degree phase delay between each other. Impedance matching is achieved using a matching structure of T-match meander line. In the second part of the thesis, we present an optimized implantable antenna transferring power and data efficiently with a low profile external transmitting antenna by utilizing RFID backscattering technique. We characterize the coupling enhancement by simulating the wireless link with head models. Prototypes are measured and characterized in terms of absorption level and channel capacity. The proposed antenna system provides wireless and fully-passive solution for multichannel neural recording systems.