Resistive multipliers use the resistance modulation of the mixer diode to generate harmonics since a mixer diode is a variable resistance device. This nonlinear capacitance in the varactor or nonlinear resistance in the mixer diode is used to generate harmonics. When driven by a sinusoidal current at an input f O , a nonsinusoidal voltage waveform rich in harmonics is generated. This harmonic generation occurs without much loss of power making frequency conversion practical. Many harmonic integers can be created and interact in the diode.
Useful integers are present along with others which are called idlers.
With filtering and matching techniques the desired x N output is obtained. Resistive multipliers are generally broadband covering an entire waveguide band but have higher losses and lower power handling ability compared to a varactor multiplier. They are typically of a balanced design. X3 multipliers have a balanced DC anti - parallel and RF parallel circuit. A typical resistive multiplier is shown in fig.