A non-foster circuit design for antenna miniaturization

In this paper, a non-Foster circuit for achieving a negative small capacitance based on Linvill floating-type Negative Impedance Convertor (NIC) is realized. The effect of the parasitic elements and the transmission lines on the circuit performance is discussed. The experimental results show that the circuit presents a negative capacitor of 0.87pF in the UHF band. The circuit linearity test reveals a high output 1dB gain compression point at 7.8dBm and an output saturation point at 15.6dBm. Furthermore, the circuit has relatively high inter-modulation Output Intercept Points (OIPs).