A Broadband High-Gain and Low-Sidelobe CTS Array Covering Entire W-Band Based on Stacked Parallel Plate Gap Waveguide

This article presents a novel continuous transverse stub (CTS) array antenna based on gap waveguide (GW) technology, where all components are integrated within a multiple-layer stacked parallel plate GW (PPGW). Furthermore, a stepped pin electromagnetic band gap (EBG) unit is proposed to enable low-loss interconnection of stacked PPGW, thereby enhancing the bandwidth and efficiency of the entire array. This architecture offers a simple assembly solution for all-metal cooperate-feed CTS arrays. For experimental verification, a W-band 32-slot CTS array is designed based on the proposed architecture. Low sidelobe level (SLL) in both E- and H-planes is attained through the combined utilization of a nonuniform cooperate-feed network and pillbox beamformers. A prototype is manufactured and tested to validate its performance. The measured impedance bandwidth covers the entire W-Band (75-110 GHz, 37.8%), and the measured peak gain is 32.3 dBi at 110 GHz. SLL in both E- and H-planes remains below -18.5 dB across the entire operating band. Furthermore, the mean radiation efficiency stands at 76.3%. The proposed architecture and design methodology are well-suited for broadband, high-efficiency, and large-scale array antennas at a low cost, which particularly appeals to upper millimeter-wave applications.