Ultra-wideband multilayer six-port junction with common phase error cancellation

A wide bandwidth and very well balanced six-port junction is reported. It makes use of recent theoretical results which show that six-port networks are extremely tolerant to common phase errors of some of its building blocks. This property can be advantageously used to implement an improved six-port juction made up of four hybrids and a 90° phase shifter. This architecture allows to completely cancel the phase errors of the hybrids yielding a total phase imbalance of the sixport junction that is below ±2.5° in the UWB band (from 3.1 to 10.6 GHz), clearly outperforming previously reported results. Its key element is a novel multisection slot-coupled phase shifter with equalized phase velocities that shows a phase shift of 90 ± 2.5° in the whole operation bandwidth.