Analysis of spherical-circular microstrip antennas on a uniaxial substrate

Many substrate materials commonly used for microstrip antennas exhibit uniaxial anisotropy, and several related studies have been published. However, these studies on uniaxial substrates have been confined to planar microstrip antennas. Since conformal capability is one of the major advantages of microstrip antennas, the study of conformal microstrip antennas on a uniaxial substrate is also worthy of investigation. This motivates the present paper for the analysis of spherical-circular microstrip antennas on a uniaxial substrate. For the study, the Green´s function in the spectral domain is first formulated, and Galerkin´s moment method incorporating the cavity-model basis functions is then used for calculating the complex resonant frequency of the microstrip structure, which gives the information of the resonant frequency and the half-power bandwidth of the patch antenna. Furthermore, the probe-feed excitation is also included in the study. The surface current distribution on the circular patch is calculated and shown. The copolarized and cross-polarized fields are also calculated.<>