Design of wideband microstrip-slot six-port complex ratio measuring unit

A wideband six-port Complex Ratio Measuring Unit (CRMU) design is presented in this paper. CST Microwave Studio is used to design the CRMU by integrating one in-phase Wilkinson power divider with stubs and three 90° microstrip-slot two-section branch-line couplers (BLCs). Wilkinson power divider is improved by implementing additional stubs at transmission line of Port 1, Port 2 and Port 3. Meanwhile, slot is placed underneath each parallel branch arm of BLC to broaden its bandwidth performance. The presented simulated result of the proposed CRMU offers good wideband performance of amplitudes and phase characteristics between 2.5 and 5.2 GHz.