The design and decoupling of TX/RX antenna with omnidirectional conical beam operating at V band

In this work, a high isolation transmitter–receiver antenna with omnidirectional conical beam operating at 61.5 GHz is presented. The proposed dual-antenna system consists of a transmitter (TX) antenna and a receiver (RX) antenna with the same structure, composed of a circular metal patch with ring slot and metal shorting vias, fed by a coaxial probe at their respective geometric center. And both antennas are placed on a circular metal platform, positioned symmetrically with each other. To increase the isolation between them, three different decoupling methods are proposed, and the one with an electromagnetic band gap (EBG) structure added in-between shows the most promising decoupling effect, as the surface wave current can be maximally suppressed. The overall size of the antenna system is 2.255 2  × π × 0.579 λ 0 3 , where λ 0 is the free space wavelength at 61.5 GHz. A prototype of the proposed antenna system with EBG decoupling structure is fabricated and measured, demonstrating that the TX–RX isolation is 57.9 dB at 61.5 GHz, 21.6 dB better than that without decoupling structure, with omnidirectional conical beam radiation achieved at the same time.