Balanced Filters With Wide Differential-Mode Passband and Efficient Common-Mode Suppression Based on a Bandpass Synthesis Method

This letter presents a synthesis-based approach for on-chip balanced bandpass filters with wide differential-mode (DM) bandwidth and enhanced selectivity, alongside efficient common-mode (CM) suppression. By employing bandpass synthesis without frequency normalization, the DM half-network is directly determined in the bandpass domain, which allows a flexibly wide passband (thanks to frequency-variant <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i>-inverters) and multiple assignable transmission zeros (TZs). The CM parameters are analyzed subsequently, where both the attenuation zeros and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i>-inverter values are adjusted for sufficient CM suppression. The approach is validated through both synthesis and experimental results, demonstrating the desired performance.