Wideband circularly polarized fan-shaped antenna on a HIS structure

A wideband circularly polarized antenna consisting of four section fan-shaped antenna is presented. A small square patch was placed at the center of structure to accommodate the power splitting with necessary phase shifting feeding circuitry. To achieve wideband circularly polarized (CP) radiation patterns, equal amplitude and sequentially rotating 0°, 90°, 180°, 270° phase difference between each section is required. A one to four way quadrifilar power divider chip was used to satisfy mentioned feeding condition. A mushroom electromagnetic band gap (EBG) structure was used as a high impedance surface (HIS) to convert the bidirectional radiation patterns to a directional one. The proposed antenna achieves an VSWR 2:1 impedance matching from 1.12 GHz to 1.61GHz (35% fractional bandwidth). The CP radiation pattern and axial ratio (AR) quality over the entire operating band is promising. This antenna shows a RHCP gain of more than 5dBic and AR below 1dB from 1.16GHz to 1.58GHz which covers the L-band satellite communication.