A Spaceborne GNSS Oblique-Beam Array Antenna With Wideband High Efficiency and Deep Adjacent-Band Filtering

In the passband, the NESM compensates for excessive reactance, reduces reactive power, and improves efficiency. In the stopband, the NESM confines surface currents to continuous metallic-boundary regions and suppresses far-field radiation, thereby inserting an efficiency zero (EZ) into the efficiency spectrum and realizing controllable AB filtering. For different impedance characteristics, stopband locations, and efficiency-enhancement regions, DRRC is classified into independent and coupled integration approaches, with corresponding efficiency–impedance theoretical maps, a design procedure, and selection criteria.

Unit-level validation shows a total efficiency higher than 85% over a fractional bandwidth exceeding 36%, together with more than 16 dB suppression in the target stopband, resolving the difficulty of reconciling wideband high efficiency with AB filtering. Furthermore, using a frequency-dispersive passive phase-gradient network, a 1 × 4-element, 22° oblique-beam (OB) Global Navigation Satellite System (GNSS) array antenna is developed.

Measurements show that the array achieves a total efficiency of >75% and an axial ratio (AR) of <3 dB over 1.15–1.65 GHz, and a 22 dB suppression depth in the 1.69–1.71 GHz target stopband. With an overall size of 2.4λ0 × 0.67λ0 × 0.13λ0 and a mass of 762 g, the proposed array verifies the effectiveness of the proposed theory for remote-sensing receiving antennas.