Miniaturized and broadband monopole antenna based on split-ring resonator and non-foster circuit

In this paper, a split-ring resonator is loaded to a monopole antenna for the purpose of miniaturization. As a result, the monopole antenna is shortened from quarter wavelength to ninth wavelength. Then, a Non-Foster circuit is loaded to the input port of the SRR-based monopole antenna. Due to the negative capacitance characteristic, the Non-Foster circuit can offset the imaginary part of the input impedance of the SRR-based monopole antenna and the bandwidth is successfully expanded.