Effect of air gap on the performance of circular sector antennas

Abstract

Theoretical analysis of a cir cular sector microstrip antenna having sector angle (α) and an air gap (<i>h</i>_a) between substrate material and ground plane is carried out by applying cavity-model-based modal expansion technique. Expressions for different antenna parameters are derived in TM₁₁ mode of excitation and the theoretical results are compared with simulated results. Average differences in computed and simulated resonance frequency, input impedance, directivity and bandwidth values for the sector geometry with air gap are found to be 1.3%, 10.25%, 0.75% and 1.9%, respectively. This validates the accuracy in proposed analysis technique for the present geometry.