Design and Simulation of Fabry-Perot Antennas

Abstract

Horn antennas are widely used in the areas of satellite tracking, communication dishes, radio astronomy, as feeds for reflectors and lenses, as common elements in phased arrays, as a standard for calibration and gain measurements in laboratories for other high gain antennas, as a medium-gain antenna, and as feed clusters for Multiple Beam Antennas (MBAs). The basic requirements of these antennas are high directivity and gain, low return loss, low sidelobe level, low cross-polarization, and a purely metallic structure. In many practical applications, increasing the gain of a horn antenna becomes one of the major requirements. The gain of the horn antenna can be increased by several methods. Two of the conventional methods are: (i) by increasing the aperture size of the horn antenna and (ii) by forming an array of horn antennas to increase the overall gain. However, these methods suffer from a few limitations including the bulkier and complex antenna structure. One of the fascinating techniques to improve the gain of a horn antenna is to place a partially reflecting surface in front of an antenna at a particular distance. In the open literature, such a concept is described as Fabry-Perot Antenna (FPA). The present work is focused on the gain enhancement of horn antenna using a Fabry-Perot cavity approach.

A Fabry-Perot Antenna (FPA) primarily consists of a radiator, a partially reflecting surface (PRS), and a ground plane. It possesses the capability of increasing the aperture efficiency of an antenna. This thesis represents a complete procedure to be followed for designing a Fabry-Perot horn antenna for various configurations like a circular waveguide, pyramidal horn, conical horn, and cluster of conical horn antennas. It includes a complete theoretical explanation for various types of material used for PRS and the performance parameters of antenna-like return loss, directivity, gain, and radiation pattern are discussed. Exhaustive parametric analysis is carried out for all the proposed antennas. There is a significant improvement in gain and directivity performance for the proposed Fabry-Perot horn antenna. For pyramidal horn and conical horn with PRS improvement of 2.21 dBi and 2.02 dBi are accounted respectively. Increment of 6.58 dB in the directivity of conical horn antenna was observed and improvement in radiation pattern is observed for conical horn and cluster of the conical horn antenna. Analytical calculations and the simulations are performed by using electromagnetic solver HFSSv2014.