A broadband sub-array of U-slotted patches for Ku-band active antenna system

Satellite mobile communications is a key link in the chain of infrastructure of global communications. A ground mobile antenna with broad frequency band, transiently steerable sharp-beam, miniaturized and low profiled structure, is specifically required for various vehicle systems. As a elemental assemblage of the active array antenna system with spatial power combining, a broadband 4/spl times/2 sub-array is developed in advance by using broadband U-slotted microstrip patch radiators and broadband stripline feed network. The main performances of this sub-array are: 23.24% bandwidth for VSWR/spl les/2:1; the beamwidth is stable within the operating band (12.25-14.50 GHz) with (30-32)/spl deg/ in the E-plane and (15-14)/spl deg/ in the H-plane. The slightly higher side-lobe-level may be suppressed by the factor of the whole array; the cross-polar-level in the E-plane is very good, but deteriorated in the H-plane at the high end of the frequency band, which may be improved by replacing the feed type.