A Novel Inter Digital Filtenna Structure with Dumb Bell Shaped and CSRR Defects in Ground for S-Band and ISM 2.4 GHz Band Applications

Abstract

Filtennas combine the filter and antenna units into a single assembly, reducing the size of the front end of the transceiver unit. This paper proposes a Filtenna with an Inter digital and Pass filter incorporated in the feed line of a leaf-shaped antenna. The ground plane of the Interdigital filter (IDF) is made dumbbell shaped DGS to boost bandwidth and reduce ripples in the pass band. In the interdigital construction, seven resonators are used, with one end of each resonator having dual vias instead of direct shorting. The antenna shape, which is inspired by the leaf shape and created using a modified polar transformation formula, is unique in this work. At 2.3GHz, the suggested model is constructed on a 1.6 mm thick FR4 substrate with dimensions of 0.250.58. Dual CSRR are used in this final model in addition to dumbbell DGS, resulting in a ripple free return loss (S11) of the final filtenna model. This type has a 1.1GHz band width from 2.3 to 3.4GHz and a maximum depth of -24.7 db at 3 GHz. The band can be found in S band mobile applications, Wi-Fi, and the ISM 2.4GHz frequency.