A compact and wideband slot antenna with conical radiation pattern using artificial magnetic conductors

This paper presents a compact and wideband slot antenna with conical radiation patterns using artificial magnetic conductors (AMC). It consists of a 4-element antenna array and an AMC surface on the upper and lower substrates, respectively. The electric fields generated by the four slot elements cancel each other in the center so that a radiation null can be generated in the center. The AMC surface is placed behind the antenna array to enhance the forward radiation. The resonant frequencies of the one-wavelength slot and quarter-wavelength monopole modes of the square slot antenna element are tuned close to each other to achieve the wideband performance. The performance of the proposed antenna in terms of S
₁₁
, radiation patterns, efficiencies, and realized gains are studied. According to the simulated results, its impedance bandwidth is from 4.99 to 6.19 GHz (1.20 GHz, 21.5%), and its maximum gain is 6.0 dBi at the elevation angle of 36°.