Non-foster active impedance circuit for electrically small antennas

An antenna comprising:

• a driven element;
• an input feed coupled to the driven element wherein the input feed is configured to be connected to a receiver;
• a conductive cage comprising three sides, wherein the conductive cage is positioned so as to encompass the driven element;
• a non-Foster circuit having a negative impedance, wherein the non-Foster circuit is configured to actively load the antenna at a location on the antenna other than at the input feed so as to achieve a bandwidth beyond a Bode-Fano limit;
• and
• a ground wherein two of the three sides of the conductive cage are in electrical contact with the ground and wherein the third side comprises two halves electrically separated by a center gap, and wherein the non-Foster circuit is mounted to both halves of the third side such that the non-Foster circuit spans the center gap, and wherein the antenna is electrically small.

A method for providing an electrically small antenna comprising the following steps:

• providing a driven element having an input feed;
• surrounding the driven element with a conductive cage;
• actively loading the antenna with a Non-Foster circuit at a location on the antenna that is not at the input feed to create an electrically small antenna with a bandwidth beyond a Bode-Fano limit;
• mounting the conductive cage to a ground, wherein the conductive cage comprises two halves, each half comprising first and second sides, wherein the first sides are mounted to the ground and the second sides of the two halves are separated from each other by a center gap;
• and
• mounting the non-Foster circuit to both halves such that the non-Foster circuit spans the center gap and actively loads the antenna at the center gap.