A Passive High‐Pass Negative Group Delay Circuit With Low Insertion Loss and Enhanced Delay Magnitude

A passive high‐pass negative group delay circuit (NGDC) based on lumped RLC networks is proposed and verified in this paper. Five high‐pass NGD topologies are first designed and evaluated under identical port impedance and frequency conditions. Among them, the Type IV topology is selected because it achieves the most balanced overall performance in terms of NGD magnitude, bandwidth, insertion loss, and circuit complexity. An equivalent shunt‐impedance model and ABCD ‐matrix equation are established to derive the transmission coefficient and group delay of the selected circuit. Parametric analysis shows that the inductors mainly control the operating frequency and NGD magnitude, the capacitor determines frequency tuning and the transition from high‐pass to band‐pass NGD response, and the resistors govern the trade‐off among NGD value, bandwidth, insertion loss, and response type. The optimized Type IV circuit is fabricated on an FR‐4 substrate and measured using a vector network analyzer. The fabricated circuit exhibits a measured characteristic NGD frequency of 240 kHz and an NGD bandwidth of 2.33 MHz. It also achieves a minimum group delay of −104.83 ns and an insertion loss of 2.03 dB. The measured figure of merit reaches 193.35 × 10 −3 , showing good agreement with theoretical and simulated results and competitive performance compared with reported high‐pass NGDCs.