Non-foster microwave circuit design for wide band active impedance matching operation

Abstract

In this research, a novel negative capacitance circuit was developed to augment the frequency bandwidth of unmatched antennas. Optimization of the transmission line and DC feeding line design parameters was carried out to ensure efficient signal transmission and minimal loss, with a transmission line width of 2.96 mm achieving a 50 Ω characteristic impedance at 2.45 GHz. Validation of the Negative Impedance Converter (NIC) circuit's performance was achieved through experimental and simulation results, demonstrating negative capacitance within the frequency ranges of 2.47–2.62 GHz and 2.77–2.93 GHz. The proposed negative capacitance matching circuit significantly enhanced the operational frequency bandwidth of the antennas by 220 %, compared to conventional open stub matching methods, presenting an effective solution for bandwidth improvement in antenna design.