Effects of Probe Feed and Soldering Point on Thick Microstrip Antennas

This paper deals with coaxial influence on electrically thick microstrip antennas. The analysis is based on a rigorous mathematical approach, using dyadic Green´s functions for stratified media. The upper conductor and the coaxial probe are broken down into rectangles and segments, over which the surface currents are evaluated by a method of moments. Special attention is turned to the attachment mode function which insures continuity and the radial distribution of current on patch. Results are obtained for both solder and solderless structures and compared with measurements. The elimination of soldering points provides a new tuning capacitive parameter, namely the gap between the tip of the probe and patch. A capacitive mode is introduced to simulate small gaps.