A low profile printed slot antenna (PSA) backed by broadband planar artificial magnetic conductor (AMC) is introduced in this study. Firstly, a suggested PSA with the radiating tapered slots excited by coplanar- waveguide (CPW) is used to expand the bandwidth in the measured range of 9–11 GHz (S11 ≤ –10 dB). Then, the suggested planar AMC surface as the ground plane of the antenna is inserted into the PSA to gain improved radiation efficiency. The realized result from the PSA with the 5 × 7 planar AMC array exhibits ‒10 dB measured impedance bandwidth from 6.63 to 13.70 GHz (almost 70%). The suggested PSA with AMC compared to the PSA without AMC exhibits a size reduction of 59.7%, enhanced bandwidth of almost 50%, and excellent impedance matching with uni-directional radiation patterns. The novel AMC unit cell is realized to operate at 10.14 GHz with an AMC bandwidth of 8–12.35 GHz (43.1%) for X-band operation. Besides, by introducing a specific method based on the reflection results of the equivalent waveguide feed, the number of AMC unit cells is investigated to obtain an optimal AMC array. In this approach, an equivalent waveguide feed corresponding to the center operating frequency is considered to choose the number of AMC array reflector.
