Interwoven Feeding Networks With Aperture Sinc-Distribution for Limited-Scan Phased Arrays and Reduced Number of Phase Shifters

Abstract

A phased-array feeding network that scans a limited region in space with low-sidelobe levels and a low number of phase shifters is investigated. The interwoven coupling network is composed of power dividers, couplers, and resistive attenuators with each phase shifter feeding all of the antennas and creating a sinc-like current distribution over the array. This results in a boxcar function-like element pattern and suppresses the grating lobes. The width of the scan region is controlled by the interelement spacing and the coupling and attenuation coefficients of the interwoven network. Different configurations along with theoretical limitations are investigated to determine the scanable region, sidelobe level, and power loss. Two prototype linear arrays with 28 elements are fabricated at 7.9 GHz. The first array employs 14 phase shifters, has a half power beamwidth (HPBW) of 4°, and can scan up to ±24° with sidelobe levels less than −15 dB. The second array uses seven phase shifters, has an HPBW of 4°, and can scan up to ±11° with sidelobe levels less than −15 dB. Both of these arrays show state-of-the-art performance in terms of reducing the number of phase shifters while resulting in low sidelobe levels over the entire scan region.