Omnidirectional Cylindrical Microstrip Patch Antenna versus Planar Microstrip Antenna - A Parametric Study

Abstract

The Industrial, Scientific and Medical (ISM) radio bands i.e. 2.4 GHz, are the radio bands reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes. Despite the intent of the original allocation, in recent years the fastest-growing uses of these bands have been for short-range, low-power communication systems. Cordless phones, Bluetooth devices, NFC (Near-Field Communication) devices, and wireless networks. Omnidirectional antennas are required to maintain an ease (proper) communication link. Conformal antennas follow the shape of the surface on which they are mounted and generally exhibit a very low profile. When these types of antenna are mounted on aircraft, missiles and instrumented artillery shells, they reduce turbulence effects in flight, because of their low profile. Low profile conformable antenna on a regular surface viz. cylindrical surface is easily achievable by conforming microstrip patch antenna on the surface. Design procedure involves parameters related to cylindrical microstrip elements to realize the desired resonant frequency, input impedance, radiation patterns etc. A radiating microstrip patch antenna mounted, as considered in this paper, on a cylindrical surface is chosen because major real world shapes can be approximated by cylindrical surface or cylindrical sector and uniformity in a plane provide ease of analysis. A microstrip line has been chosen to feed the patch antenna as this feed design provides very small stray radiation from the feed and is simplest geometry for theoretical analysis & practical manufacturing. Computer aided design of microstrip antennas and its analysis are based on efficient and accurate numerical methods using IE3D software. This paper presents microstrip patch antenna with the effect of design parameters such as substrate thickness and dielectric constant of the substrate on the design frequency of cylindrical patch antenna and compare the results with planar microstrip antenna. Considering the effect of design parameters, a method for accurately determining the resonant/design frequency of such structures have been obtained. Antenna efficiency and Radiation efficiency of the antenna were obtained. The graphs were studied to see their conformance with theoretical performance.