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.
