Compact Cavity-backed Magneto-Electric Dipole Array Filtenna Using Hybrid Coupled-resonators

This paper presents a new design approach for filtering antenna (Filtenna) array. The main idea is to use a hybrid configuration of coupled-resonators as a feed network of the array. With this purpose, the non-radiative combline and radiative rectangular cavities are effectively adopted to control the inter-element spacing of the array and resonant behaviour of the filter. The magneto-electric (ME) dipoles are loaded to the radiative cavities to provide the desired radiation profile and output quality factor for antenna and filter, respectively. For demonstration, a fourth-degree $2\times 2$ array of cavity-backed ME dipole Filtenna is implemented by hybrid resonators operated at X-band frequencies. The synthesized and simulated results agree well and show return loss of −15 dB (over 600 MHz bandwidth), flat realized gain of 10 dB and a steep roll-off out of band rejection.