Study of bandwidth and radiation properties of loaded annular ring antenna

Loading of microstrip antennas provides dual frequency, tenability and compactness. In this paper a theoretical method is developed to calculate various parameters of loaded annular ring antenna via. Shorting pins. The pins are located symmetrically i.e. equispaced along the circumference of the annular ring. Various parameters such as input impedance, bandwidth, return loss, quality factor and radiation properties are calculated. The theoretical results results are in good agreement. TM01 is the dominant mode of propagation for the loaded annular ring antenna. The radiation properties are more directional when the antenna is loaded and the bandwidth is also enhanced.