Design and development of a stacked complementary microstrip antenna with a “π”-shaped DGS for UWB, UNII, WLAN, WiMAX, and Radio Astronomy wireless applications

Abstract

The proposed research paper presents the design, development, and experimental testing of a broadband stacked complementary microstrip antenna for ultra-wideband (UWB) (5.28–5.85 GHz), Unlicensed National Information Infrastructure band (UNII) (5.25–5.825 GHz), wireless local area networks (WLAN, IEEE802.11a, 5.15–5.35 GHz), and IEEE 802.11b (5.75–5.85 GHz), Worldwide Interoperability for Microwave Access band (5.25–5.85 GHz), and Radio Astronomy band (6.6–6.75 GHz) wireless applications. The main aim of this paper is to obtain an UWB behavior from the combined effect of two resonances exhibited by the driven and parasitic patches of a stacked complementary antenna geometry. Circularly polarized radiations are also emitted by the antenna by the addition of an orthogonal stub to its feed line. The proposed three-layered antenna structure (without air gap) is fabricated on commercially available glass-reinforced epoxy laminate, FR4 substrate. The topmost layer of FR4 has a square-shaped patch parasitic patch printed over it; this patch has a square slot etched out from it. The middle layer of the antenna has a square-shaped driven patch of approximately the same dimensions as that of the slot in parasitic patch. The antenna is fed using aperture-coupled feeding mechanism. Therefore the lowermost layer of FR4 has a ground plane on its top with a “π”-shaped slot etched from it and a feed line with an orthogonal stub at its bottom forming a “T”-shaped geometry. The antenna is fed by the electromagnetic coupling between the antenna layers .The proposed antenna has a compact structure with overall volumetric dimensions of 4.7 × 3.82 × 0.483 cm3. The antenna design and simulations are carried out using CSTMWSV'10 with perfect boundary (electric and magnetic) estimations. This designed antenna shows an UWB behavior from 5.14 to 5.85 GHz with an impedance bandwidth of 710 MHZ and a fractional bandwidth of 12.62% at the center frequency of band at 5.5 GHz. The radiating antenna also possesses a good gain of 4.59 dBi at the central frequency of 5.50 GHz and a 1 dB axial ratio bandwidth of 820 MHz from 5.16 to 5.98 GHz. The validation of results is done by fabrication and experimental testing of the antenna using a vector network analyzer and placing the antenna in an anechoic chamber for gain measurements. The measured results show close matching with the simulated ones and this makes the antenna well suited for the proposed wireless applications of interest, specifically in small handheld wireless communication devices.