A broadband 100 GHz phase switch/mixer using a uniplanar slotline transition

We have developed a broadband 180/spl deg/ phase switch using one-sided planar grounded slotline design. The design is based upon a grounded coplanar waveguide (CPW) to slotline transition acting as a balun. This design offers several advantages over existing topologies making it well suited to monolithic microwave integrated circuit (MMIC) integration. The uniplanar construction allows for simple module integration and the slot transition with a cutoff frequency serves the same function as a waveguide transition used in multipliers and mixers. We fabricated a switch using flip-chip Schottky diodes and demonstrated the circuit as a W-band phase switch and a mixer. The switch has 5 dB insertion loss and phase flatness of 10/spl deg/ from 90-110 GHz. As a mixer the circuit performs with 12 dB conversion loss from 76-112 GHz, with an IF bandwidth exceeding 25 GHz. This performance is comparable to commercially available waveguide mixers, which are incompatible with MMIC integration.