Reconfigurable Antenna for Modern RF Front -Ends

Abstract

Antennas are necessary and critical components of communication and radar systems, but sometimes their inability to adjust to new operating scenarios can limit system performance. In recent years, there has been a growing need for multiband and multimode transceivers for various wireless applications. This is due to multiple wireless standards for which various architectures addressing multi-band and multimode transceivers have been reported. There is an increasing trend to merge several applications into one device. Therefore, there is a need for reconfigurable circuits. Making antennas reconfigurable so that their behavior can adapt with changing system requirements or environmental conditions can eliminate these restrictions and can provide additional levels of functionality for any system. We have developed a reconfigurable microstrip antenna that has multiple resonant frequencies that can be dynamically reconfigured by varying the voltage across the varactor diode surface mounted on the antenna. The antenna has been designed for the unlicensed ISM band and has a tunable frequency range above 700 MHz (1.9GHz to 2.5GHz), covering a large number of wireless standards such as Bluetooth, WiFi 2.4G, GSM 1900, ZigBee, GPS, UMTS etc. Advantages of reconfigurability are lower overall costs, smaller system size and high market potential. Reconfigurable antennas have recently received significant attention for their applications in communications, electronic surveillance and countermeasures, many military and commercial applications where it is desirable to have a single antenna that can be dynamically reconfigured to transmit and/or receive on multiple frequency bands.