An integrated Butler matrix in multi-layer technology for multi-port amplifier applications

Abstract

The elements of the matrix - 3 dB/90/spl deg/ coupled-line directional couplers and cross-overs - have been designed in multilayer technology, optimised and tested individually, and then merged to form the whole integrated 4 /spl times/ 4 Butler matrix. A good performance of the manufactured matrix, operating in the frequency band 2-4 GHz, encouraged us to design a four-channel amplifier with four input- and four output ports, in which monolithic amplifiers are surface-mounted into 50 /spl Omega/ microstrip lines connecting the input and output Butler matrices. Very promising experimental results are shown.