Design of a Low Panel Profile and High Selective Filtering Transmitarray With Electrical Beam Steering

This article presents the design of a novel transmitarray (TA) integrated with a dual function of filtering and electrically reconfigurable beam. The TA is capable of 2-D beam scanning while simultaneously suppressing out-of-band noise with a high selectivity and low panel profile. The TA element is composed of two filtering patch antennas connected back-to-back, with one side of it being 1-bit reconfigurable. The first radiation null (RN) is brought by the coupling between the main patch and the parasitic elements, and the second one is introduced by a pair of symmetrical slots. Owing to the RNs brought by the filtering antenna, the TA element realizes a high selectivity and good out-of-band suppression while keeping a very low profile of 0.08λ₀. Additionally, two p-i-n diodes are mounted between the feeding strip and the radiator to enable a 180° phase change of the element. A TA with 12 × 12 cells is then designed using the element designed above. Apart from the magnitude of the main beam, the gain flatness is also optimized during the synthesis of the TA to guarantee a good in-band response. As a result, a filtering TA operating from 5.33 to 5.88 GHz with a panel profile of only 0.08 λ₀, high selectivity, good out-of-band suppression, and beam scanning within ±40° by electrical control in both planes is realized.