Design and Analysis of Frequency Reconfigurable Dielectric Resonator Antennas

Abstract

In this thesis different types of frequency reconfigurable dielectric resonator antennas are designed for various wireless communication applications. Wireless communications now a days are becoming a piece of everyday existence of individuals. Thus to attain efficient and reasonable communication, conservative and proficient radiators are needed. Surely, one of the productive radiators is Dielectric resonator antenna (DRA). The reconfiguration capacity maximizes the antenna performance in a changing scenario. Frequency reconfiguration can be achieved by switching parts of the antenna “ON” or “OFF”. Different switches such as pin diodes, varactor diodes, MEMS switches etc. are used for this purpose. In this thesis, first a simple dielectric resonator antenna with microstrip strips on two edges of the dielectric resonator is designed. The dielectric constant of the DR is taken as 𝜀𝜀𝑟𝑟 = 10 with dimensions 13mm×13mm×10mm. The DR is placed on a ground plane of dimensions 100 mm × 150 mm and substrate of 𝜀𝜀𝑟𝑟= 3.38. By usingshorting tabs on one edge of the DRA, six different operating conditions are obtained. Second, a H shaped frequency reconfigurable DRA using coplanar waveguide (CPW) feed is presented. This antenna consists of two dielectric resonators of dielectric constant 15 each. The DRs are placed on a substrate of dielectric constant 3.2. CPW feeding technique is used to excite the DRA. Two PIN diodes are used on the line connecting the dielectric resonators. Using these PIN diodes 3 operating modes, such as OFF ON, ON OFF and ON ON are obtained. In OFF ON state 2 bands with center frequencies 2.7 GHz for WLAN application and 4.8 GHz for INSAT (Indian national satellite system) application are obtained. In ON OFF state a single narrow band with center frequency 3.7 GHz is obtained for WLAN and international mobile telecommunications (IMT) applications. Similarly in ON ON state a dual band with frequencies 2.6917 and 5.2589 is obtained for WLAN applications. Finally, an aperture coupled dielectric resonator antenna with power divider is designed. First of all the antenna is analyzed without any PIN diodes and later the frequency reconfigurability is obtained by using PIN diodes in the feed network. In the first case a single band with center frequency 2.9 GHz is obtained for WLAN applications. Later by using switching elements 3 different operating frequencies are obtained