Low-Cost Periodic Sparse Cavity-Backed Phased Array Based on Multiport Elements

In this communication, an H-plane sparse cavity-backed antenna array is proposed, and by using multiport elements, the number of array control components such as transmitting/receiving modules, phase shifters, and power dividers is reduced, and therefore cost of the phased array is saved. In the array, each subarray consists of an active and a passive element, and the active element not only works as an antenna but also as a power divider to feed the passive one. A reflection-type phase shifter (RTPS) is designed and integrated between the two elements, whose phase shift is controlled by two reflective loads. The distance between the neighboring active elements is ( is the free-space wavelength at the center of the operating frequency band), twice of that between the active and the passive elements. Meanwhile, cavity-backed structure is adopted to obtain unidirectional radiation patterns with high aperture efficiency. The proposed array can be used in both wide-angle scanning and limited field-of-view applications. Simulated and measured results are given and discussed to validate the proposed idea.