Dielectric resonator oscillator and down converter using the same

A microwave oscillation circuit comprising:

• a metal plate having a first surface, a second surface and a screw hole penetrating said first and second surfaces;
• a dielectric substrate having a surface securely contacting said second surface of said metal plate;
• field effect transistor for generating a microwave oscillation mounted on said dielectric substrate, said field effect transistor having at least a gate terminal and a source terminal;
• a micro strip line provided on said dielectric substrate, a first end of said micro strip line connected with the gate terminal of said field effect transistor and a second end of said micro strip line grounded to said metal plate via a terminal resistor, forming a circuit on said dielectric substrate;
• a shield case for shielding the circuit on said dielectric substrate;
• a dielectric resonator secured on an inner wall of said shield case;
• and
• a tuning screw coupled to said screw hole at said first surface of said metal plate, said tuning screw penetrating said metal plate and said dielectric substrate;
• wherein said micro strip line and said dielectric resonator are coupled and an oscillation frequency output is obtained from the source terminal of said field effect transistor and the oscillation frequency is adjusted by rotating said tuning screw to i) penetrate said dielectric substrate and ii) vary a distance between said tuning screw and said dielectric resonator.