Transmit-Receive Isolation Improvement of Antenna Arrays by Using EBG Structures

The mushroom-like electromagnetic band-gap (EBG) structure combined with a choke structure is applied to improve the transmit-receive (T/R) isolation of two X-band large antenna arrays. The basic idea presented is to suppress the surface wave propagation between the T/R arrays by utilizing EBG walls formed through a vertical configuration of the EBG cells, so as to improve the T/R isolation. The isolation level of the arrays with the EBG walls and a metal choke is measured and compared to other isolation methods applied. The experimental results show that by using this combined structure, the isolation level can be improved by at least 30 dB in the radar's operation band, which shows its high efficiency.