A non-foster monopole array

Antenna arrays enable beamforming and multiple-input multiple output (MIMO) communication schemes, but performance suffers as the element size and spacing is reduced. A non-Foster matching network for an electrically-small 2-element monopole array is proposed to overcome the performance limitations of passive matching. Full-wave simulation and stability analysis show that the proposed network is stable and the reactance of both the even and odd modes can be cancelled simultaneously over a wide bandwidth using ideal negative capacitors and negative resistors.