Noise performance of an antenna matching network with negative-impedance converter (NIC)

Non-Foster matching networks seem to be useful for the matching of small antennas. This paper presents the design and the functionality of such a non-Foster matching network with a negative impedance converter (NIC). It is realized with active elements and generates additional electronic noise in the matching network. Therefore a careful investigation and comparison with a conventional matching network regarding the signal-to-noise (SNR) performance of the overall antenna system has to be made. As example a small monopole antenna for automotive application in the FM frequency range is used. In contrast to other publications a severe SNR disadvantage of the non-Foster network results. This shows that for the efficient design of small active antennas with non-Foster matching networks realized with NICs a careful noise investigation has always to be performed.