Gain Enhancement of a CPW-Fed Monopole Antenna Using Polarization-Insensitive AMC Structure

A polarization-insensitive dual-band artificial magnetic conductor (AMC) structure is designed and experimentally verified. It consists of a planar array of annular ring-slot loaded rectangular patches. Details of the proposed structure and origin of the two bands is discussed. Through simulations and measurements, it is shown that the structure is insensitive to polarization of the incident wave. The tuning of the higher AMC band is demonstrated by varying the capacitance of the annular slot through its width variation. The designed AMC is used as a reflector for a wideband monopole patch antenna. It is shown experimentally at the antenna frequencies in the AMC band that the gain of the antenna improves by almost 10 dB and front-to-back ratio is improved by 15 dB.