Isolation enhancement in dual-polarized patch antennas using TM21 and TE20 modes for 6G sub-THz transceiver applications

This study focuses on enhancing isolation in dual polarization antennas operating at different modes in order to suppress coupling between transmitter (Tx) and receiver (Rx) without using any additional decoupling modelling. To validate the proposed investigation approach, a transmitter antenna was simulated at 150 GHz in vertical polarization (V-Pol), and the Rx works at 180 GHz in horizontal polarization (H-Pol). Later, both Tx and Rx were coupled in such a way that they excite in orthogonal directions to each other, implying that the angle between Tx and Rx is approximately 90 degrees. In this case, the Tx will function in TM21 resonance mode, having an operational bandwidth of 10 GHz at 150 GHz. While Rx will operate in TE20 mode, with an operational bandwidth of more than 10 GHz at 180 GHz. This research achieves more than 30 dB isolation simply by allowing Tx and Rx to operate in different modes under an orthogonal feeding setup. The proposed antenna provides better than |S12| > 30 dB isolation with an isolation bandwidth of 51.42% in the sub-THz range from 130 GHz to 220 GHz without the need for an extra decoupling mechanism. Finally, the results of the proposed research were validated using HFSS and FEKO electromagnetic tools to explain simulation outcomes such as return loss, isolation, radiation efficiency, peak gain, and radiation patterns.