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What specific array configurations yield a bidirectional pattern with deep, symmetrical nulls at exactly ±90° from boresight in the H-plane?

Bidirectional H-plane patterns require careful selection of element spacing and phasing. Two-element broadside arrays spaced λ/2 with in-phase feeding create nulls at ±90°. Endfire arrays with 180° phase difference can achieve similar results. Larger arrays with amplitude tapering further control null depth and beamwidth. Designers combine simulation and measurement to fine-tune patterns for precise null placement.

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By Shashank Answered 1 year ago

The classic configuration is a three-element, equally spaced linear array. To get peaks at 0° and 180° and nulls at ±90°, use an out-of-phase excitation for the center element relative to the two outer ones. Specifically, for elements spaced λ/4 apart along the H-plane axis, feed the two outer elements with amplitude +1 and phase 0°, and the center element with amplitude -2 and phase 0°. This creates an array factor approximating a sin²(θ) or cos²(θ) pattern. The exact null depth and beamwidth depend on the spacing and amplitude ratio. You can refine this using Dolph-Chebyshev or binomial synthesis for a two-element array with specific spacing and unequal excitation, but the three-element approach is more straightforward for achieving symmetrical, deep nulls at those specific angles.

 

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