Inconsistency in Modes of Circular Microstrip Antennas and Its Rectification

Inconsistencies in the interpretation of modes in Circular Microstrip Antenna (CMA) has been brought out and explained. The prevalent methods for CMA modes have been shown to be inconsistent with standing wave equation. It is emphasized that the current or field maxima along radius, diameter or half-circumference, have been incorrectly used to infer the mode indices in various books and academic papers. This paper aims to bring out the disconnection between mathematical model and physical interpretation of CMA modes. Further, a method to accurately interpret modes of CMA has been presented and has been demonstrated. Additionally, the presented method has been extended to annular ring antennas.