Self-Decoupling Method for Closely Packed Full-Duplex Dual-Band Microstrip Patch Antenna Array

In this letter, a self-decoupling method for closely packed dual-band microstrip patch antenna array for the application of full-duplex system is developed. The low-band (LB) decoupling is realized by minimizing the field distributions along the adjacent edges of the two radiating patches. The high-band (HB) decoupling is achieved through the mechanism of coupling cancellation, wherein the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i>-field densities along each radiating edge of the antenna element can be individually modulated. Both decoupling methods were implemented by strategically introducing shorting pins to the radiating patches. The developed self-decoupled array demonstrated isolation enhancement up to 20 dB and 17 dB in the LB and HB, respectively. A prototype was fabricated with dimensions of 0.64λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.58λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.023λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub>, where λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> is the wavelength at 3.5 GHz. Good agreement between the measured and simulated results is achieved.