A Unilateral 6-GHz 2 1/2-Watt Varactor Quadrupler

Abstract

Absfracf-A unilateral 1.5-to 6-GHz varactorquadruple has been developed. The multiplier delivers 2+ watts at 50-percent conversion efficiency and has a maximum inputVSWR of 1.6 for all conditions of load impedance. The quadruple efficiencyis diode limited, not circuit liiited, with only 0.5 dB of the 3.O-dB conversion loss due to circuit losses. The design uses a unilateral circuit concept for even-order harmonic generators to achieve the low sensitivity to output mismatch and a balanced diode pair hybrid circuit configuration to reduce chcuit complexity and circuitloss. Varactor multiplier stages are often cascaded using isolators to improve the stabiEty. The use of unilateralmultipliers eliminates the necessity for such isolators.

Submillimeter-Wave Quasi-Vertical GaAs Schottky Diodes Integrated on Silicon Membranes

“…The work presented here applies this architecture to implement an integrated frequency quadrupler with output frequency of 160 GHz using quasi-vertical GaAs varactors fabricated on thin silicon support membranes. The use of a balanced circuit architecture to realize "unilateral" multipliers that are insensitive to the loading effects of the output stages appears to have been first proposed by Gewartowski in 1964 [94] who later applied this approach to realize a quadrupler with 2.5 W of output power at 6 GHz [95]. The quadrupler presented here makes use of the same basic approach, but differs from that of Gewartowski as it uses a second-stage balanced doubler at the output to generate the fourth harmonic.…”