Compact structure with high TX-RX isolation for frequency domain duplexing on printed circuit boards

摘要

When developing compact and lightweight antenna systems for unmanned aerial systems, achieving high isolation between transmit and receive signal paths is challenging. To address this issue, we demonstrate a prototype isolation design on a printed circuit board for a frequency division duplexed X band antenna system. Key components include a microstrip defected ground plane notch filter and a copper grating barrier that provides 20 dB higher isolation than free space separation between the transmit and receive antennas. The hardware provides at least 105 dB of transmit isolation into the receiver low noise amplifier in the transmit band. The proposed design is lighter and more compact than traditional machined metal waveguide isolation techniques used for ground-based systems yet achieves similar isolation performance.