Switchable and tunable multiband slot dipole antenna

Abstract

Developments of frequency reconfigurable antennas in the wireless communication systems have attracted a lot of attention recently. Most reported antennas have narrowband to narrowband reconfiguration and multiband to multiband reconfigurations. In this research, a slot dipole antenna has been introduced with the ability to produce a multiband to narrowband reconfiguration. This type of antenna can suppress the problem of co-site interferences. Thus, two types of frequency reconfigurable antennas are studied and discussed which are switchable and tunable multiband antennas. The switchable multiband antenna is reconfigured by using Radio Frequency (RF) switches. The proposed antenna is capable to reconfigure from multiband to dual and/or single band. By having seven configurations of switches, this antenna can operate at 2.4 GHz, 3.5 GHz and/or 5.2 GHz. The antenna is able to have three states of single-band, three states of dual-band and one state of tripleband. Meanwhile, the tunable multiband antenna is reconfigured by using variable capacitors. The proposed antenna is capable to have a wide frequency tunability range for dual or single band operation (1.5 GHz - 4.5 GHz, ratio of 3:1). Each antenna has been successfully designed, fabricated and tested. The simulation and measurement results were analysed and presented in terms of reflection coefficient, radiation pattern and gain. The simulation and measurement results have been compared and a very good agreement was achieved. The reflection coefficient average accuracies of 98% has been achieved. These proposed antennas are suitable for future multi-mode applications such as cognitive radio systems.