Design of a dual band frequency reconfigurable patch antenna for GSM and Wi-Fi applications

Reconfigurable antennas due to their versatile qualities are highly demanded nowadays. A novel frequency reconfigurable patch antenna with two metallic rings around a rectangular patch is presented in this paper. Frequency reconfigurability can be achieved by changing the radiating surface of antenna. Surrounding metallic rings are connected to center patch with switches. The antenna operate in 1.8 GHz and 2.4 GHz frequency bands, when the switches are turned ON and OFF respectively. When the switches are turned ON they add external rings to radiating surface, hence increasing the surface size which in return changes the operating frequency of antenna. Different types of switching elements like MEMS, varactor diodes PIN diodes or optical switches can be used depending upon the nature of application. In this paper optical switches are chosen due to their advantage of not interfering with antenna radiation characteristics due to no need of biased lines. Antenna presented in this paper can be reconfigured to operate on Wi-Fi (2.4 GHz) and GSM (1.8 GHz) frequencies at a time. The antenna gives directivity and efficiency of (7.89 dBi, 48 %) and (8.2 dBi, 93 %) at 1.8 GHz and 2.4 GHz respectively. CST (Computer Simulation Tool) is used for design and simulation of proposed antenna.