Self‐Decoupled Microstrip Patch Antenna Array for In‐Band Full‐Duplex Systems Based on Magnetic Currents Coupling Cancellation

In this article, an effective self‐decoupling method based on magnetic current coupling cancellation is presented to facilitate the isolation improvement of a closely spaced E ‐plane coupled microstrip patch antenna (MPA) array. By introducing three short‐circuit vias to the antenna element, the electric field intensities along the radiating edges of the antenna element can be effectively regulated. The coupling from the radiating edges of the active antenna element cancels out each other to achieve high port isolation. A mirror‐arranged two‐element transceiver MPA array with center‐to‐center spacing of ~0.33 λ ₀ and edge‐to‐edge spacing of 0.05 λ ₀ is fabricated and measured. The measured results exhibit a port isolation level of more than 41 dB over the −10 dB operating bandwidth, and a maximum level of 71 dB is observed. A prototype of the developed self‐decoupling MPA array was fabricated and measured; good agreement between the simulated and measured results was achieved.