Large-Signal Calculations for the Overdriven Varactor Upper-Sideband Upconverter Operating at Maximum Power Output

Abstract

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 ≦ ω3/ωc ≦ 0.1) sufficient to include most practical design.