An Efficient Analog Self-Interference Canceller Using a Balanced Topology for Mitigating Inherent Multi-Tap Loss

Addressing self-interference in dynamically changing multipath environments for co-located high-power transmit and receive systems is a significant challenge. This paper presents a new topology based on the energy conservation balanced architecture, by using pure reflective discontinuities designed to mitigate the inherent N-path network synthesis and tuning mechanisms losses respectively for suppression. To validate the performance of the proposed topology, a network of eight grounded coplanar waveguide 90-degree hybrids is designed and fabricated on Rogers 4350B and commercial off-shelf digitally tunable capacitors. The prototype operates between 1.8 GHz to 2.4 GHz and demonstrates a passive emulator gain of −3dB. This research presents a leakage suppression topology designed for optimal efficiency, catering to full-duplex applications across frequency bands with low antenna isolation.