A Chamfered Pyramidal Potter Horn Antenna With Low Sidelobe Level and Cross Polarization

Abstract

In this letter, a chamfered pyramidal Potter horn antenna is designed with both low sidelobe level (SLL) and low cross-polarization level (XPL). First, a stepped discontinuity structure is introduced to excite the TM₁₂ mode. By precisely controlling the amplitude and phase of the TM₁₂ mode through structural adjustment, low SLL and low XPL performances are achieved. In addition, simple chamfered structures are also applied to change the electric field distribution across the horn aperture, which further reduces the XPL of the pyramidal horn antenna. Finally, the antenna is fabricated and measured. Measurements demonstrate excellent E-plane and H-plane symmetry with low SLL across 23.5 GHz to 29.5 GHz, achieving a bandwidth of 22.6% with XPL lower than −30 dB. The E-plane SLL remains below −25 dB throughout the operating band. Note that the proposed pyramidal Potter horn achieves an unprecedented minimum measured XPL of −37.8 dB.