GaAs varactors for broad-band paramps

P-N and M-S epitaxial GaAs varactors have been developed for broad-band parametric amplifiers. At, zero bias the varactors have a junction capacitance of 0.15 pF, and a cutoff frequency of 700 GHz when measured at 70 GHz. Millimeter wave measurements indicate a series inductance of 0.08 nH and a shunt capacitance of 0.025 pF, These unusually low values for the parasitic elements have made it possible to achieve beyond the state-of-art broad-band and low-noise amplification.