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2 years ago in Antenna & RF Design By Rohini Singh

What causes beam squint in offset circularly polarized antennas, and how can it be mitigated?

Offset circularly polarized antennas are designed to reduce blockage and improve polarization purity, yet beam squint—frequency-dependent shift of the main lobe—is often observed. I want to understand the electromagnetic and geometric reasons for this phenomenon and strategies to minimize squint in design and fabrication.

 

All Answers (1 Answers In All)

By Trideep Das Answered 1 year ago

From my experience with offset circularly polarized antennas, I have seen that beam squint arises primarily from frequency-dependent phase variations across the aperture and misalignment between the feed and reflector. The offset geometry introduces asymmetry, and as frequency changes, the effective path lengths from feed to aperture vary, causing the main lobe to shift. I would recommend careful optimization of feed position and phase center, and, if possible, using broadband matching networks or aperture tapering to reduce frequency sensitivity. In practice, minor squint is often inevitable in wideband designs, but simulations combined with experimental measurements allow designers to predict and minimize angular deviations while maintaining circular polarization integrity.

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