Design of a Compact Dual Band Microstrip Antenna for Ku-Band Applications

Abstract

ABSTRACT A new design of dual band compact microstrip antenna is proposed for Ku-band applications.Dual band is achieved using three pairs of thin slits from the sides of a rectangular patch and feeding with a microstrip feed line.The result shows that a return loss of -32.9dB is achieved at the first resonant frequency of 12.72GHz, and -14.4dB is obtained at the second resonant frequency of 14.4GHz frequency with VSWR ≤ 2indicating improved matching conditions. The results ofsimulation are return loss, radiation pattern, VSWR, and band widtharepresented. The design is performed by using Ready-madeSoftware package Zeland- IE3D. The antenna is fabricated using thin film and photolithographic technique and measured using the Vector Network Analyzer. The final result shows that good agreement between the simulated and measured results. Keywords Microstrip antenna,Ku-band, Dual band 1. INTRODUCTION Microstrip antennas have been one of the most innovative topics in antenna theory and design in recent years, and are increasingly finding application in a wide range of modern microwave systems [1]. Inherently they have numerous advantages like easy to fabricate using standard integrated circuit techniques, have microstrip lines [1low profile, are conformal, and can be easily integrated in arrays with electronic components. Nevertheless, microstrip antennas typically suffer from narrowband radiation (a few percent of center frequency), low gain, poor polarization purity, tolerance problem and limited power capacity. However, applications such as frequency tuning take advantage of the inherent narrow bandwidth of the microstrip antenna. Systems such as satellites, global position system(GPS) are required to operate at two different frequenciesthat are very far from each other. Microstrip antennas canavoid the use of two different single band antennas. A variety of methods has been proposed to obtain dual frequency operation. Such as loading slits [2], using slots in the patch [3], [4], loading the patch with shorting pins [5], [6] and [7], using stacked patches [8], [9], [10] and[11] or using two feeding ports [12] are the most exploited ones. In addition, there are planar antennas of special geometries fto achieve dual-bandoperation [13]. The Federal Communication Commission adopted a First Report and Order (First R&O) to permit non-geostationary satellite orbit (NGSO) and fixed-satellite service (FSS) providersto operate in various segments of the Ku-band, and adopted rules and policies to govern these operations. NGSO FSS can provide a variety of new services to the public, such as high-speed Internet access, other types of high-speed data, video and telephony services. Because of its ability to serve large portions of the earth’s surface, NGSO FSS can bring advanced services to rural areas. The Commission also adopted technical criteria so that NGSO FSS operations can share spectrum with incumbent services on a co-primary basis without causing unacceptable interference to them andwithout unduly constraining future growth of incumbent services or NGSO FSS system flexibility [14]. In this paper, a simple new compact design of single layer single patch element with microstrip feed line is proposed for dual frequency operation in Ku-band. The design and optimization resulted in a downlink frequency of 12.72GHz and uplink frequency of 14.4GHz. The most obvious application in the Ku-band is aircraft, spacecraft and satellite based communication system.