Reconfigurable Quad-Band Antenna for Wireless Communication

Abstract

This letter presents a thorough procedural investigation of a highly compact reconfigurable quad-band monopole antenna providing multiband operation at 1.85 GHz (GSM 1900 MHz), 2.42 GHz Bluetooth/IMTE, 3.4 GHz (Wi-MAX) and 5.3 GHz wireless LAN (WLAN) for personal wireless applications (PWA). The investigated antenna structure consists of a ‘5′- shaped stub that facilitates operation for GSM applications and a semicircular arc for Bluetooth/IMT-E applications, while an inverted L-shaped stub facilitates dual-band operation for Wi-MAX and wireless LAN applications. The presented antenna is fed using an asymmetrical coplanar strip-line (ACS) feed. The triple-band frequency reconfiguration operation, over the Bluetooth, Wi-MAX, and WLAN frequency bands, is achieved by embedding two PIN diode RF switches. The investigated antenna is developed on a highly economical FR-4 glass epoxy substrate that is 1 mm thick with a compact size of 24 × 10 mm2. The presented antenna has measured impedance bandwidths of 1.7–1.91 GHz (BW = 11.63%), 2.35–2.55 GHz (BW = 10.31%), 3.3–3.7 GHz (BW = 11.428%) and 5.10–5.6 GHz (BW = 9.345%) providing frequency reconfigurable quad-band operation at the aforementioned frequency bands. The antenna offers simulated gains of 1.8, 3.45, 4.91 and 0.86 dBi; measured gains of 2.3, 2.7, 2.82 and 2.6 dBi and radiation efficiencies of 83%, 61%, 82% and 86% at 1.85 GHz, 2.42 GHz, 3.4 GHz and 5.3 GHz, respectively. The investigated antenna exhibits nearly symmetrical radiation patterns and stable acceptable gains across all application bands, thus making the antenna suitable for wireless communication.