Experimental Demonstration of Non-Foster Self-oscillating Huygens Radiator

An extension of the basic concept of a self-oscillating non-Foster cross-dipole to a self-oscillating Huygens radiator has been developed theoretically and studied numerically. A proof-of-concept prototype has been built. The realized antenna consists of two orthogonal dipole-loop pairs, a negative impedance converter, and a tuning LC circuit. In this paper we report the basic concepts and the initial results obtained with a scaled RF demonstrator operating in the 60 MHz regime. The preliminary results have demonstrated self-oscillations with nearly-perfect admittance matching over a tuning bandwidth of 1:1.35. The familiar cardioid-like radiation pattern was achieved as designed across the 10% relative bandwidth. These results confirm the efficacy of the basic idea of self-oscillating non-Foster Huygens radiators.