Multilayer Dielectric Resonator Antenna Transmitarray for Near-Field and Far-Field Fixed RFID Reader

A design of multilayer dielectric resonator antenna transmitarray for fixed radio frequency identification (RFID) reader applications is presented at 5.8 GHz. Three layers square dielectric resonator antenna (DRA) elements are mounted on dielectric substrate and used as a unit cell in the transmitarray. A circularly polarized 9 × 9 square DRA transmitarray is designed at 5.8 GHz for far-field RFID applications. The transmitarray produces maximum gain of 20.2 dB. The right-hand circular polarization level is lower than -31 dB at the designed frequency with SLL of -22 dB. A design of 9 × 9 near-field focused DRA transmitarray for fixed RFID at 5.8 GHz is investigated. The properties of the near field-focused transmitarray are compared with that of the far field transmitarray designed at the same operating frequency.