A RECONFIGURABLE SQUARE RING SLOT ANTENNA FOR OPERATION IN GSM AND WLAN FREQUENCY BANDS

Abstract

This dissertation presents the design of a reconfigurable square ring-slot antenna for wireless communications and wireless local area network (WLAN) applications. The multitude in different standards in cell phones and other personal mobile devices require compact multi-band antennas and smart antennas with reconfigurable features. The use of the same antenna for a number of different purposes, preferably in different frequencies is highly desirable. The proposed design demonstrates reconfigurability in frequency. The operating frequencies are 1.8 GHz, 2.4 GHz and 5.2GHz. The use of PIN diodes is proposed to implement the switches that are connected across the slot, at appropriate locations along with the matching stubs. The proposed frequency reconfigurable square ring slot antenna is designed using IE3D simulation software. The antenna consists of a square ring-slot on a square metal ground plane that is fed by a T-shaped microstrip line. The basic square ring-slot structure resonates at 1.8 GHz. By introducing shorts at appropriate positions across the slot and providing properly designed matching stubs, the antenna can be made resonant at 2.4GHz and 5.2 GHz frequencies. For a non-reconfigurable design, shorts can be provided by metallic strip connection, but in the reconfigurable design, they are to be implemented with an electronic switch. To reconfigure the matching network, pin diodes have been used to connect or disconnect the stubs from the microstrip feed Iine and, also, shorts at appropriate position on the slot have been implemented using the pin diodes. The proposed compact reconfigurable slot antenna may be used for WLAN (2.4-2.484 GHz), (5.15-5.34 GHz) and other practical wireless communications systems, such as global system of mobile communications (GSM) (1.8-1.1.88 GHz) and Bluetooth Industrial-Scientific-Medical (ISM) (2.4-2.484 GHz)