8×8 Butler high power matrix at L-band

This paper presents a Butler Matrix with 8 input ports and 8 output ports. It uses 3 dB branch line couplers, phase shifters, and TNC coaxial connectors, all of them linked by means of U-shape TEM transmission lines. The design is focused in high power (220 watts) application, low PIMP and multipaction free criteria being used. Finally, optimization of the mass figure is also a key design goal. An Engineering Qualification Model was manufactured and subjected to RF, environmental and high power testing. Details of the design as well as test results are presented.