Triple Band Microstrip Patch Antenna for Public Protection and Disaster Relief Using Aperture Coupled Feed

Abstract

Public Protection and Disaster Relief (PPDR) is a matter of great concern for the citizens, the Governments and RF solutions are an essential element for Public Safety operations. Currently, all public safety communication system in India use narrowband radios. The narrowband nature of these system restrict them to 2-way voice communications with no additional support for high-bandwidth transmission requirements such as high quality photographs, interactive video communication, floor plans and remote video surveillance of security or disaster sites. Usually, a radiating structure is required to support multiple standards. The performance and advantages of microstrip patch antennas such as low weight, low profile, and low cost made them the perfect choice for communication systems engineers to be used for PPDR. The aim of this dissertation is to develop a microstrip Patch Antenna that exhibits the highbandwidth requirements within WiMAX and public safety bands. WiMAX (Worldwide Interoperability for Microwave Access) is the best suited for the application, as WiMAX has three allocated frequency bands from 2.5 -2.8 GHz, 3.2-3.8 GHz and 5.2-5.8 GHz. A triple band Microstrip Patch Antenna is designed that operates at 3.6 GHz, 5.2 GHz and 5.8 GHz. Only two i.e. middle band and high band is incorporated in the antenna to support high bandwidth requirements. The 3rd band used for Public safety band i.e. 5.850-5.925 GHz (according to IND73 of the National Frequency Allocation Table for PPDR in India). Since microstrip patch antennas have a low bandwidth, a special feeding technique named aperture coupling was implemented. This technique helps and makes it possible to use a low permittivity patch substrate with a large thickness. With the help of this configuration a broadband microstrip patch antenna can be realized. The U slots are used to ensure the triple band operation, helped in increasing the bandwidth and give the efficient results. The antenna is designed using CST Microwave Studio 2010.