Investigation of higher order modes excitation through F-shaped slot in rectangular dielectric resonator antenna for wideband circular polarization with broadside radiation characteristics

摘要

In this article, a wideband circularly polarized rectangular dielectric resonator antennarn(RDRA) with broadside radiation characteristics has been proposed. By using modifiedrnground plane having an F-shaped slot, the proposed structure able to generatesrnthree sets of modes i.e., fundamental as well as higher order modes. To obtainedrncircular polarization, an orthogonal mode (TE113) in the RDRA has been generatedrnby using the F-shaped slot on the modified ground plane. The resonance frequency ofrnfundamental mode (TE_(111)) in the rectangular dielectric resonator (DR) has been calculatedrnby using dielectric waveguide model method. The same has been confirmedrnthrough E-field distribution in RDRA. Here, wide axial ratio (AR) bandwidth of thernproposed antenna is due to the generation of TE_(113)~x and TE_(113)~y modes. It is observedrnthat input impedance bandwidth has been broadening with a pair of excited modesrn(TE_(121)~x and TE_(121)~y modes) in the proposed antenna structure. All these modes havernbeen excited and merged to form a wide input impedance bandwidth and wide ARrnbandwidth of the designed antenna. The proposed antenna shows measuredrninput reflection coefficient (S_(11) < -10 dB) of 50.55% and measured AR bandwidthrn(AR < 3 dB) of 14.28%. The designed antenna shows left-handed circular polarizationrnin broadside direction and offering an average gain and radiation efficiency ofrn4.29 dBic and 92.22% respectively.