Which antenna technique directly helps suppress a jammer by steering a null toward its direction?

• A. Beamforming to increase SNR
• B. Polarization diversity
• C. Using a broadband omnidirectional antenna
• D. Phased-array beam steering to direct nulls at jammed directions and create high-gain beams

Answer: (D)

Shaping the antenna’s radiation pattern with a phased array lets you place a deep null in the jammer’s direction while preserving a high-gain beam toward the intended signal. By carefully adjusting the relative phases (and amplitudes) of the array elements, the waves from the jammer add destructively in its direction, reducing received interference. At the same time, the same weightings steer energy constructively toward the target, boosting the signal-to-noise ratio. This ability to dynamically suppress interference by steering nulls is what makes phased-array beam steering particularly effective for jamming scenarios. Other methods either can’t create a directional null or don’t offer the same ability to maintain high gain toward the legitimate signal, so they’re less effective at directly suppressing a jammer.