Design of a wideband eight-way single ridge substrate integrated waveguide power divider

Recently, a low-loss X-band eight-way compact substrate-integrated-waveguide (SIW) power combiner was developed with about 40% bandwidth. To further widen the operating bandwidth, ridges can be added to form a ridge SIW (RSIW). RSIW has many advantages, such as a low profile, light weight, low cost and planar structure and wide bandwidth. In this study, a 1 to 8 splitter for an array antenna feed based on RSIW technology has been designed and fabricated that encompasses an extended bandwidth beyond that of the conventional guides. The divider is comprised of a GCPW to RSIW transition, RSIW T-junction and 90° bend and has demonstrated over a 65% bandwidth with better than 10 dB return loss from 5 to 10 GHz. In particular, it demonstrated excellent amplitude and phase uniformity with less than ±0.3 dB and ±5° imbalance, respectively, within 5.5 to 9.6 GHz.