5:1 Bandwidth Dielectric Rod Antenna Using a Novel Feed Structure

We present an ultrawideband dielectric rod antenna using a novel V-shaped twin-wire tapered transverse electromagnetic waveguide as the feed structure. The new feed taper allows for much wider bandwidth and resolves the pattern degradation in higher frequencies, which is typically encountered in endfire mode dielectric rod antennas. The three sections of the antenna geometry, namely, the feed taper, the rod body, and the radiation taper, are concurrently designed to achieve a 5:1 frequency bandwidth covering 6-30 GHz, 17-dB maximum gain and sidelobe levels below -20 dB over the entire band. The design is fabricated using Rexolit_1422 (epsilon_r = 2.53) and measured performance is compared with simulation results, illustrating the effectiveness of the new feed structure in providing 5:1 bandwidth with stable radiation patterns within the entire band.