ANALYSIS AND EXPERIMENT OF A RIDGED HORN ANTENNA WITH METALLIC GRID SIDEWALLS

A ridged horn antenna with metallic grid sidewalls is proposed and quantitatively analyzed. Simulated and measured results indicate that the operating band is from 1.0 to 20.0 GHz with the reflection coefficient less than −10 dB, and the relative bandwidth is as high as 180.95%. The gains are greater than 10 dBi in the frequency band of 2.6–20 GHz and greater than 16 dBi in the frequency band of 10–20 GHz with the gains fluctuation less than 1 dB. In the whole operating band, the radiation patterns radiate directionally along the normal direction of the horn aperture and do not split. In this paper, the ridged horn antenna with metallic girds is analyzed quantitatively. A modified equivalent traveling wave current model of the ridged horn antenna is proposed, which matches better to the patterns of the ridged horn antenna in high frequency band. The working mechanism of metallic grid sidewalls is also analyzed quantitatively, and the reason that metal strips can improve the matching performance of ridged horn antenna in low frequency band, restrain the patterns splitting in high frequency band, and improve the antenna gains is explained. The proposed antenna has the characteristics of ultrawideband, stable gains, miniaturization, and directional radiation patterns with no splitting main lobe in ultra-wideband. The proposed ridged horn antenna can be used for the measurement in a microwave anechoic chamber.