A Compact Power Combining 180-GHz Frequency Doubler Using Y-Junction Direct Matching

This letter presents an extremely concise and compact power combining Schottky-based 180-GHz frequency doubler using the Y-junction match. In contrast to the conventional power combining configurations with complex power divider/combiner networks, interconnected waveguides, and single doubler, this work employs a direct matching approach to match the optimal embedded impedance of the diode. The Y-junction applied in this letter provides power dividing/combining, impedance matching, and microstrip (MS) to waveguide transitions in one structure. This structure not only significantly reduces the difficulties associated with waveguide manufacturing but also simplifies the circuit-matching process, thereby minimizing waveguide length loss. A 180-GHz power combining frequency doubler has been demonstrated based on this prototype. The measurement results show that the doubler delivers continuous wave (CW) input power of 500 mW with the output of 76 mW from 168 to 189 GHz. The peak output power is 108 mW at 182 GHz with 500-mW pumped.