Radiation-Q bound of a small non-Foster antenna

Abstract

Within this article the fundamental limit of Q of an antenna with non-Foster elements will be proposed. The Chu's fundamental radiation Q-limit of small antennas has been revisited for non-Foster small antennas, where non-Foster elements are assumed to be within the radiansphere. In the case, where non-Foster circuits are not part of the antenna itself, the fundamental limit for matching a high-Q antenna defined by Bode-Fano has been revisited using non-Foster matching technique. Furthermore, this paper will discuss how non-Foster antennas (NFAs) can overcome the fundamental Chu's limit of small antennas depending upon the consideration of non-Foster elements as a part of antenna itself. Also, simulation results of Q-bound curve for a test antenna has been verified with measured non-Foster element.