Realization of In-Band Full-Duplex Antenna Self-Decoupling Based on MultiLayer PCB Vertical Feeding and TE₂₁₁ Mode Dielectric Resonator

This paper presents a self-decoupling in-band full-duplex (IBFD) antenna array for wireless WLAN and digital satellite communications. High isolation is achieved using the TE211 higher-order mode of the dielectric resonator antenna (DRA), eliminating the need for additional decoupling structures. The study concludes that the mechanism for achieving isolation is due to the near orthogonalization of the TE<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">211</inf> mode and the mode produced by spatial coupling, resulting in a very low level of mutual coupling. To adapt to multilayer PCB application scenarios, a vertical feeding structure based on substrate integrated waveguide (SIW) is designed. Short-circuited microstrip stub is placed internally and resonate with the coupling slot on the top layer. Simulation results indicate that the S21 is below −64 dB at 5.81 GHz, with a gain of 7.35 dBi. Notably, bandwidth with isolation below −40 dB reaches 4.3% (5.7-5.95.GHz) and S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> below −10 dB.