Coupled RF signal cancellation based transceiver arrangement for backscatter communication

The isolation between Tx and Rx port is essential for long range backscatter communication. Coupler has long been used to isolate transmitter and receiver ports but isolation offered by a microstrip coupler is limited. This work proposes a transceiver system at 2.45 GHz with an isolation better than 75 dB between transmit and receive ports. The system comprises of novel arrangement of power dividers, couplers, patch antennas with a λ/2 line for RF cancellation. RF cancellation technique is used in the current system to achieve additional isolation. The positioning of λ/2 line also results in unique Transmit and receive radiation pattern and antenna coupling cancellation along with additional 30 dB isolation.