Dual-Band Filtering Slot Array Antenna for W-Band Application

A co-aperture dual-band linearly polarized slot array based on ridge gap waveguide (RGW), operating at the 74 - 78 GHz and 102 - 106 GHz bands, is designed. In each subarray, two groups of longitudinal slots for two frequency bands are excited by a single RGW channel to achieve dual-band unidirectional radiation. Additionally, grooves and notches are implemented inside the RGW structure to improve dual-band matching, and two bandpass filters (BPFs) are incorporated at each side of the subarray to realize independent dual-band feeding while also providing filtering characteristics. The proposed subarray operates as a single channel. It can expand into a multichannel array, enabling multiple-input multiple-output (MIMO) when each subarray is individually excited or broadside radiation when all subarrays are simultaneously excited. A planar array of four subarray columns was fabricated to validate the dual-band concept and its broadside radiation performance. The simulated and measured results show good agreement.