Modified Designs of U-slot Cut Microstrip Antennas for Wider Bandwidth

Abstract

Wideband design of coaxially fed U-slot cut patch is a widely reported configuration. It yields a bandwidth of 20–25% on a substrate thickness of 0.06–0.07 λ_g. In all the reported designs, narrower U-slot has been used as it yields required impedance matching to achieve the wideband response. In this paper, initially a detailed study is presented to explain the effects of employing wider U-slot in the rectangular patch to achieve the wider bandwidth. A further modified design of U-slot cut rectangular microstrip antenna is presented, to achieve the impedance matching using a wider U-slot. The modifications in the U-slot cut patch yield optimum possible impedance around the patch TM₁₀ resonant mode that optimizes the loop position inside VSWR = 2 circle, to achieve the maximum bandwidth. Variations using different values of the vertical U-slot lengths have been investigated. In all those variations, impedance bandwidth in the range of 26–30% is achieved in the 950 MHz frequency band, which is 5% higher when compared with narrow U-slot designs. Furthermore, a pair of rectangular slot-cut design of modified U-slot cut antenna is presented, which yields further 5% increment in the bandwidth. Similar designs with circular patch are also proposed which yield more than 5% increase in the bandwidth. In addition to the bandwidth increment, the proposed designs yield nearly 20% reduction in the patch copper area. Proposed antennas yield a broadside radiation pattern with a peak gain of 9 dBi.

KEYWORDS:

• Broadband microstrip antenna
• Coaxial feeding
• Narrower U-slot
• Rectangular microstrip antenna
• Wider U-slot

Additional information

Notes on contributors

Venkata A. P. Chavali

Venkata A P Chavali received BE degree in electronics and communication engineering from Andhra University, Vizag, India in 2004 and ME degree in digital communication from RGPV, Bhopal, India in 2010. Currently, she is pursuing the PhD degree in electronics and telecommunication engineering from D J Sanghvi College of Engineering under Mumbai University, Mumbai, India. Since 2012 she has been working as assistant professor with Electronics and Telecommunication Engineering Department, D J Sanghvi College of Engineering, Mumbai, India. Her research interests include broadband microstrip antennas.

Amit A. Deshmukh

Amit A Deshmukh obtained BE in electronics from VIT Pune University in 1997. He obtained MTech degree in 2000 and PhD in 2004 from the Department of Electrical Engineering, IIT Bombay. His thesis work during masters and doctoral was on microstrip antennas. Currently, he is working as professor and head of the EXTC Department at DJ Sanghvi College of Engineering, Mumbai. He has published more than 150 research papers in various international and national journals and conferences. Email: [email protected]