A Review of Low Profile Single Layer Microstrip Antennas

Abstract

The modern wireless systems call for integrating multiple applications. There are numerous techniques available to cater these demands. However the need for thin, light weight and compact wireless applications call for the design of low profile and single layer antennas with multiple features. Hence, this paper deliberates on the comprehensive review of compact, low profile, and single layer microstrip antennas suitable for fifth generation (5G) wireless applications, wireless local area network (WLAN), worldwide interoperability for microwave access (Wi-Max), and other state of the art wireless applications. The techniques discussed here consider the performance improvement of one or more parameters of the antenna. These parameters include the improvement of impedance (10dB return loss) bandwidth, gain, 3dB axial ratio (AR) bandwidth, improvement of isolation between the ports in multiple input multiple output (MIMO) antennas, and excitation of dual modes/dual polarization/circular polarization. Antennas with all such techniques and their advantages, applications & limitations have been discussed in detail. The studies presented here on single layer planar antennas offer a maximum impedance bandwidth of up to 68%, highest axial ratio bandwidth of 46%, and 11.6dBi gain for single element & 25.6dBi gain for arrays. Other significant findings covered are antennas with triple bands operation, arrays with less than -37.5dB mutual coupling and compact antennas with more than 60% reduction in physical area. In addition to the advantages and applications, their limitations and drawbacks are also discussed.