An adaptive array for high speed wireless local loops steered by local signal phase shifters

We propose an adaptive array steered by local signal phase shifters for high-speed wireless local loops. An adaptive array used as a radio receiver usually requires one or more frequency conversion sections to achieve acceptable sensitivity performance. The phase shift and the frequency shift of the signal from each antenna element can be accomplished simultaneously at the down-conversion stage by phase-controlled local signals. The configuration can avoid the additional loss or noise in the received signal due to the phase shifter itself, and ordinary commercial quadrature modulator ICs for mobile communications can be utilized for the CW local phase shifter. The adaptive array does not require high speed digital signal processing sections with fast AD converters for all of the array elements. In this paper, we describe the practical configuration of the array as well as pattern measurements in the S-band for a prototype including the essential elements.