A Compact Antenna for GPS Anti-Jamming in Airborne Applications

Null-steering using adaptive antenna systems is a robust method to global positioning system (GPS) receivers against hostile jamming. Conventionally, multi-antenna arrays have been utilized for such receivers, but the size and weight are often prohibitive especially for space-limited airborne applications. In this paper, we present another approach based on antenna pattern and polarization diversity to enable null-steering, and propose a design with co-located elements to achieve a small footprint. As a proof-of-concept, we present an antenna prototype with a size of only 5 × 5 × 1.9 cm³ (0.26λ × 0.26λ × 0.1λ) at the L1 band, capable of steering two nulls. We present the simulated and measured parameters of the antenna, study its null-steering performance in various interference scenarios with a simple power minimization method, and demonstrate its capability in suppressing up to two jamming signals incident from the angular region close to horizon.