Antenna–Filter–Antenna-Based Wideband Filtering Transmitarray Antenna

A wideband filtering transmitarray antenna (TA) based on antenna–filter–antenna structure is presented. To achieve the wideband performance, two identical receiving and transmitting dipoles with wideband impedance matching are designed, as well as a third-order stripline filtering phase shifter with stable and continuous phase shift is proposed. To further demonstrate the operational principle of the TA element, the equivalent circuit model is established and investigated based on filter theory. For experimental validation, a TA prototype with 15 × 15 proposed wideband elements is designed, processed, and measured. A wide 3 dB gain bandwidth spanning from 4.36 GHz to 5.74 GHz (28%) is realized, along with commendable filtering performance. At the center frequency of 5 GHz, a gain of 25.8 dBi, coupled with an aperture efficiency of 39.5%, is achieved. The proposed TA is confirmed to be a viable option for achieving wideband filtering performance.