A Novel Decoupling Method for Two Closely Placed Miniaturized Antennas

In this letter, we propose a novel decoupling method for two closely placed miniaturized antennas with small-sized ground. The antenna array consists of a TX-antenna and a RX-antenna, with a center-to-center distance of only 0.216 λ0, and a ground size of 0.22 λ₀ × 0.32 λ₀. Miniaturized antenna is achieved by exciting TM1/2,0 mode using shorting vias and blind vias. The size of the proposed antenna's radiation patch is just 0.104 λ0 × 0.104 λ0. A cavity-like decoupling channel beneath the antenna is designed and achieves good decoupling. A closely placed 1-TX 1-RX antenna array operating at 2.4 GHz has been designed, fabricated and measured to validate the proposed decoupling method. The measured maximum isolation reached -43.7 dB. This study proposes a new decoupling method for two closely placed ultra-small antennas.