A compact wideband circularly polarized SIW horn antenna for K band applications

Abstract In this manuscript, a compact wideband circularly polarized (CP) substrate integrated waveguide (SIW) horn antenna is presented. The proposed antenna is implemented on a substrate with a thickness of 3.1 mm (0.22 λ 0 at 21 GHz central frequency). An antipodal tapered slotted structure is embedded inside the flared part of antenna to obtain a CP converter. The fabricated antenna occupies 36.2 × 27.6 × 3.1 mm 3 (2.58 × 1.96 × 0.22 λ 0 3 ) producing a maximum gain of 11.2 dBi. The measurements of presented antenna exhibit 40% (17–25.5 GHz) relative impedance bandwidth in which the reflection coefficient and axial ratio are below −10 dB and −2.6 dB, respectively. The simulation results are in good agreement with measurements.