Compact UWB Slot Antenna With Dual‐Circular Polarization and Improvement of CP Performance

ABSTRACT This study presents an ultrawideband (UWB) slot antenna with a dual‐circular (left‐ and right‐hand) circular polarization. The presented circularly polarized (CP) antenna involves 45° oriented patches cooperating with I‐ and L‐shaped stubs fed by a directional coupler. Using a directional coupler produces orthogonal electric fields to generate CP operation, and as a result of the cooperation between patches and stubs, antenna CP performance is improved. The fabricated antenna, including two microstrip ports, occupies an area of 50 × 50 × 1.016 mm 3 . By stimulating each antenna port independently, it is possible to obtain right‐hand circular polarization (RHCP) and left‐hand circular polarization (LHCP). The experiments show that the antenna being presented has an operating frequency of 116.14% (2.87–10.82 GHz) and an axial ratio bandwidth of 33.97% (7.11–10.02 GHz). Furthermore, a stable radiation pattern was also measured for the antenna, which had a maximum gain of 2.77 dBic in the operating frequency band.