Voltage controlled oscillator including a dielectric resonator provided with a C-shaped electrode and method of regulating oscillation frequency thereof

A voltage controlled oscillator comprising:

• a circuit board having a major surface;
• a dielectric resonator on said major surface of said circuit board;
• and
• a metal case mounted on said circuit board so as to shield said dielectric resonator,
• said dielectric resonator comprising:
• a dielectric body having an upper surface, a lower surface and a side surface,
• a C-shaped first electrode provided in the interior of said dielectric body having a first portion which forms an inductance and a second portion which forms a capacitance,
• wherein said first portion of said C-shaped first electrode comprises a conductor having two opposite ends, and said second portion of said C-shaped first electrode comprises a gap defined between said two opposite ends,
• a planar second electrode arranged opposite an upper side of said first electrode and opposed to said first electrode through a part of said dielectric body,
• a planar third electrode arranged opposite a lower side of said first electrode and opposed to said first electrode through another part of said dielectric body,
• a signal extracting pattern extending from said first electrode to said side surface of said dielectric body, and
• first, second and third earth extracting patterns extending from said first, second and third electrodes, respectively, to reach said side surface of said dielectric body.