Wideband Design of a Suspended Planar Dipole Antenna with Double-tuned Impedance Matching

A low-profile wideband suspended planar dipole antenna with capabilities of wide impedance bandwidth and stable gain is proposed. To achieve this, a pair of long slots approximately λ/4 in length is formed between two rectangular patches, which serve as the dipole arms. The antenna comprises two horizontal rectangular patches, a vertical semi-rigid coaxial cable, and a square ground plane. By combining the parallel resonant characteristics of the wide planar dipole with the series resonant characteristics of the open-ended λ/4 slots, double-tuned impedance matching is achieved. This results in a wide impedance bandwidth of about 56%, centered at 2.6 GHz, with a stable gain ranging from 8.9 to 9.8 dBi across the band.