High Permittivity CPW-SIW Power Divider for Antenna Feed Networks in Airborne Phased Arrays Applications

An extremely compact design of a power divider in Substrate Integrated Waveguide (SIW) and fed by means of a Coplanar Waveguide (CPW) line is presented in this paper. The proposed solution presents a relative low insertion loss and good adaptation (measurements show an S
11
better than −20 dB for the centre frequency and below −15 dB for a 30% bandwidth) in X-band, despite the use of a substrate with a high dielectric permittivity (ε
r
= 9.8). In order to validate the design, various topologies of the power divider are manufactured, measured and compared with the simulated data. These power splitters will be implemented in the feed network of a phased array for an airborne radar system with Digital Beamforming capabilities operated by the German Aerospace Center.