Noise measurements of a non-Foster circuit for matching of a receiver antenna

A non-Foster circuit has been designed for broadband matching of antenna impedance. This matching network is used to achieve bandwidths for electrically small antenna (ESA) that exceed Chu's limit for passive antennas. The study of noise in non-Foster matching circuits is critical because of the effects of active components on the signal to noise ratio (SNR). This is specifically important for receive-type antennas. The non-Foster circuit discussed here is a floating open circuit stable (OCS) negative impedance converter (NIC) with a capacitive load. The noise figure of the non-Foster circuit is measured (9dB-14dB) in the frequency range of 100 MHz to 500 MHz and compared with simulation data. SNR analysis of the receiver antenna has been performed, and improvement of the SNR using non-Foster matching has been achieved.