High-gain wideband low-profile antenna

When trying to increase the bandwidth of antennas based on high-impedance surfaces, the radiation pattern tends to split near the resonance frequency of the artificial perfect magnetic conductor (PMC). This problem is solved here by reducing the size of the PMC in the E-plane and by making it nonperiodic in the H-plane. Using a dual-dipole as a radiating element, a 30% impedance bandwidth is achieved with directivity larger than 9 dB over the whole useful band. In view of the antenna's horizontal dimensions, this is close to the maximum achievable directivity. The total antenna height is 0.15 lambda, where lambda corresponds to the wavelength at the highest frequency. A study of the surface currents on the patches supports the phenomena observed on the radiation patterns. (c) 2006 Wiley Periodicals, Inc.