Negative resistance dielectric oscillator and equivalent circuit

Shown is a negative resistance dielectric oscillator and its equivalent circuit . In the figure, FET is a field effect transistor, ATT is the output attenuator, Rs and
Ro are the source self-bias resistor and the gate stabilizing load resistor respectively. The dielectric resonator is equivalent to a high-Q parallel resonant circuit connected in series with the gate
circuit. The capacitive strip in the figure is designed to increase the amount of feedback, and increasing its length results in stable oscillation conditions. The drain
achieves good AC grounding through the ^/4 open line; the ^/4 open line connected to the power supply forms a low-pass filter {
the distance between the two ^/4 open lines is ^, 4 dielectric wavelength, thereby achieving the power end AC isolation from drain.
    The frequency of the local oscillator is determined by the signal frequency and the intermediate frequency frequency. In order to reduce the requirements for the oscillation device used in the local oscillator,
a low local oscillator oscillation frequency is usually selected, that is, the oscillation frequency can be low.