An Amplifying Tunable Transmitarray Element

In this letter, a transmitarray element with electronically tunable and amplifying features is proposed. This transmitarray element consists of stacked patches, an amplifier, and reflection-type phase shifters. The linearly polarized wave is converted into the guided wave by the receiver patch. After modulation of the phase shifters and amplifier in the transmission line, the guided wave is lastly reradiated by the transmitter patch. The proposed design is supported by full-wave electromagnetic simulation and verified through waveguide simulator experiment. The measuring results show that the designed transmitarray element achieves over 400^° of phase shift in a broad band from 4.95 to 5.5 GHz. The introduction of the amplifier makes it produce the average gain of 7.7 dB. Furthermore, the proposed transmitarray element has a very small longitudinal size (~ 0.135λ), and it is easy and low-cost to fabricate. Thus, this transmitarray element could be developed for potential applications in several areas where high gain and beam steering are needed.