Large-signal calculations for the overdriven varactor upper-sideband upconverter operating at maximum power output

When a varactor frequency upconverter is used as the output device in a communications transmitter, it is often desirable to operate at maximum power output. For such operation, the design procedure includes a large-signal analysis under overdriven conditions, requiring the use of a computer for solution. Equations for the instantaneous varactor charge, current, and voltage are derived assuming that only three currents are present: those corresponding to the signal, pump, and output frequencies. Numerical solutions corresponding to maximum power output are obtained for both graded-junction and abrupt-junction varactors. Values of power output, conversion efficiency, input impedances, load impedance, and bias voltage are presented for ranges of drive level (1 to 2) and varactor quality (0.001 ≦ ω
3
&omega
c
0.1) sufficient to include most practical designs.