A Single-Layer S/C/K/Ka Bands Shared Aperture Antenna with Novel Feed Structure For K/Ka Bands

A shared structure antenna design working in S/C/K/Ka bands is proposed in this paper. Resonances in S and C bands are achieved using a stepped impedance slot antenna. The slot antenna also works as the ground plane for the K/Ka bands antenna. For K/Ka bands, a novel feed structure is designed to excite three patch elements working at 24 GHz, 26 GHz, and 28 GHz. It consists of a single circular loop that can excite multiple antenna elements by identifying suitable feed points based on its current and voltage distribution. The feed structure is simple, compact, and requires no additional layer to accommodate it. Measured gains of 3.58 dBi and 4.79 dBi are observed in S and C bands with a bandwidth of 0.27 GHz and 0.9 GHz, respectively. K/Ka-band antenna has a bandwidth of 7.1 GHz and gains of 7.91 dBi, 11.34 dBi, and 10.94 dBi at 24 GHz, 26 GHz, and 28 GHz, respectively. The design has a compact structure and accommodates multiple frequency bands, finding its application in 5G sub-6 GHz communication (3.5 GHz), intelligent transportation systems (5.9 GHz), and 5G millimeter wave (24 GHz, 26 GHz, 28 GHz) applications.