Non-Foster Design for Antennas

We propose a simple but robust technique for Non-Foster circuitry design for antennas. Proposed technique can match antennas of different type and, thus, it is able to move beyond the usual Non-Foster dipole matching applications. It consists of introducing an additional port inside the antenna and loading of the port with a negative network. As shown, the novelty of the technique lies in reproducing a selected part of an ideal impedance (using only series negative elements) that would perfectly match the antenna at the full length of the examined frequency window. Proposed method is demonstrated by transforming a narrow resonant patch to a very broadband and much smaller antenna. More specifically, its original 2% impedance bandwidth (-10dB) is increased to an impressive 100% bandwidth. Moreover final antenna is 2 times smaller (1/4th of its original size).