A D-Band Bidirectional Amplifier Utilizing Lossy U-Boosting Network

This paper proposes a D-band bidirectional amplifier using a lossy U-boosting network with off-state transistors, embedded inductors, and a Wheatstone-bridge-like feedback network to enhance Mason’s invariant while increasing MAG/MSG. When the boosted Mason’s invariant becomes negative, conventional gain-plane optimization is ineffective. To address this limitation, a ν-plane is introduced that remains valid for any magnitude/sign of U and whose trajectory is directly inferred from circuit parameters without approximation.