Multiple beam stripline network for phased array applications

The design and manufacture of printed beamformer components for an I-band ( approximately 9 GHz) phased array are described, together with some measured results. A 5000 element phased array has been designed employing monopulse tracking techniques and capable of scanning out to +or-45 degrees over a conical volume of scan. Elevation sum ( Sigma ) and difference ( Delta ) beams are generated using an etched stripline circuit incorporating digitally controlled, 3-bit phase shifters to scan the beam. Azimuth Sigma and Delta beams are formed in a waveguide network feeding into the elevation networks via 'magic tee' couplers. Waveguide is used in the early stages of the beamforming network because of the high power handling requirement in a full sized, operational array. Dielectric filled stripline may be used for the elevation networks where power is distributed over many boards.