Dual-Band High Gain Circular Microstrip Array Antenna for Wireless Applications

Abstract

This paper presents the design of a compact, high-gain, dual-band microstrip antenna array composed of four circular patch elements. Traditional antenna arrays employ linear or planar configurations, where the feed network plays a key role in shaping the beamwidth and sidelobe level. In contrast, this design achieves compactness by nesting a small-scaled two-element linear array within a larger two-element linear array. Each radiating element is a circular microstrip patch designed for operation at 3.1 GHz and 6.9 GHz, aligning with IEEE 802.11b/g wireless communication standards. The full array configuration operates over dual bands, covering (3.05–3.18) GHz and (6.9–7.0) GHz, and achieves measured peak gains of 11.3 dBi at 3.1 GHz and 11.2 dBi at 6.93 GHz. The observed gain enhancement results from the constructive interference between in-phase radiating elements and the use of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda/4$</tex> impedance-matching transformers, which reduce reflection losses and improve radiation efficiency which reaches 99%.