Distributed biasing of differential RF circuits

A distributed balun is presented as an alternative to inductor-based biasing of active differential circuits. The new scheme has broad bandwidth with low loss and is suited to broad-band multifunctional RF and microwave circuits. Additionally, the distributed biasing circuit discriminates between differential and common-mode signals leading to high common-mode rejection. Measured gains, centered at 580 MHz, of a selected pseudodifferential amplifier using the new biasing circuit confirm the underlying theory.