Resonator with external conductor as resonance inductance element and multiple resonator filter

A resonator comprising:

• an external conductor having upper and lower walls;
• a variable resonance capacity element comprising
• a hollow dielectric cylinder having inner and outer surfaces and upper and lower end portions facing the upper and lower walls, respectively, of said external conductor a suitable distance away,
• a first fixed electrode composed of a metal thin layer that adheres around the inner surface of said hollow dielectric cylinder and has a lower end portion electrically connected to the lower wall of said external conductor and an upper end portion separated from the upper wall of said external conductor,
• a second fixed electrode composed of a metal thin layer that adheres around the outer surface of said hollow dielectric cylinder to define a circumferential space with said external conductor and has an upper end portion electrically connected to the upper wall of said external conductor and an lower end portion separated from the lower wall of said external conductor, and
• a hollow or solid cylindrical movable electrode that is coaxial with said first and second fixed electrodes and is attached to the upper wall of said external conductor so that an insertion length of said movable electrode into said hollow dielectric cylinder can be varied;
• an input terminal having an inner conductor;
• an output terminal having an inner conductor;
• two inductance elements or two capacity elements connected in series at a connection point between said input terminal and said output terminal for compensation of transmission characteristics;
• and
• means provided in said circumferential space for connecting said second fixed electrode to the connection point of said two inductance elements or said two capacity elements in a high-frequency fashion.

A filter comprising:

• a common external conductor having upper and lower walls;
• a plurality of variable resonance capacity elements including top and last resonance capacity elements connected in series in a high-frequency fashion and each comprising:
• a hollow dielectric cylinder having inner and outer surfaces and upper and lower end portions facing the upper and lower walls, respectively, of said external conductor a suitable distance away,
• a first fixed electrode composed of a metal thin layer that adheres around the inner surface of said hollow dielectric cylinder and has a lower end portion electrically connected to the lower wall of said external conductor and an upper end portion separated from the upper wall of said external conductor,
• a second fixed electrode composed of a metal thin layer that adheres around the outer surface of said hollow dielectric cylinder to define a circumferential space with said external conductor and has an upper end portion electrically connected to the upper wall of said external conductor and an lower end portion separated from the lower wall of said external conductor, and
• a hollow or solid cylindrical movable electrode that is coaxial with said first and second fixed electrodes and is attached to the upper wall of said external conductor so that an insertion length of said movable electrode into said hollow dielectric cylinder can be varied;
• an input terminal having an inner conductor;
• an output terminal having an inner conductor;
• and
• means provided in said circumferential space for connecting said second fixed electrode to the top resonance capacity element of said plurality of resonance capacity elements to said inner conductor of said input terminal;
• means provided in said circumferential space for connecting said second fixed electrode of the last resonance capacity element of said plurality of resonance capacity elements to said inner conductor of said output terminal in a high-frequency fashion.

A resonator comprising:

• an external conductor having upper and lower walls;
• a variable resonance capacity element comprising
• a first fixed electrode composed of a metal hollow cylinder having a lower end portion fixed to the lower wall of said external conductor and an upper end portion separated from the upper wall of said external conductor,
• a second fixed electrode composed of a metal hollow cylinder that is provided coaxially with said first fixed electrode to define a gap between them and a circumferential space with said external conductor, and has an upper end portion fixed to the upper wall of said external conductor and an lower end portion separated from the lower wall of said external conductor, and
• a hollow or solid cylindrical movable electrode that is coaxial with said first and second fixed electrodes and is attached to the upper wall of said external conductor so that an insertion length of said movable electrode into said first metal hollow cylinder can be varied;
• an input terminal having an inner conductor;
• an output terminal having an inner conductor;
• and
• means provided in said circumferential space for connecting said second fixed electrode to the inner conductor of said input terminal and the inner conductor of said output terminal in a high-frequency fashion.

A resonator comprising:

• an external conductor having upper and lower walls;
• a variable resonance capacity element comprising
• a first fixed electrode composed of a metal hollow cylinder having a lower end portion fixed to the lower wall of said external conductor and an upper end portion separated from the upper wall of said external conductor,
• a second fixed electrode composed of a metal hollow cylinder that is provided coaxially with said first fixed electrode to define a gap between them and a circumferential space with said external conductor, and has an upper end portion fixed to the upper wall of said external conductor and an lower end portion separated from the lower wall of said external conductor, and
• a hollow or solid cylindrical movable electrode that is coaxial with said first and second fixed electrodes and is attached to the upper wall of said external conductor so that an insertion length of said movable electrode into said first metal hollow cylinder can be varied;
• an input terminal having an inner conductor;
• an output terminal having an inner conductor;
• two inductance elements or two capacity elements connected in series at a connection point between said input terminal and said output terminal for compensation of transmission characteristics;
• and
• means provided in said circumferential space for connecting said second fixed electrode to the connection point of said two inductance elements or said two capacity elements in a high-frequency fashion.

A filter that comprising:

• a common external conductor having upper and lower walls;
• a plurality of variable resonance capacity elements including top and last resonance capacity elements connected in series in a high-frequency fashion, provided at suitable intervals and comprising
• a first fixed electrode composed of a metal hollow cylinder having a lower end portion fixed to the lower wall of said external conductor and an upper end portion separated from the upper wall of said external conductor,
• a second fixed electrode composed of a metal hollow cylinder that is provided coaxially with said first fixed electrode to define a gap between them and a circumferential space with said external conductor, and has an upper end portion fixed to the upper wall of said external conductor and an lower end portion separated from the lower wall of said external conductor, and
• a hollow or solid cylindrical movable electrode that is coaxial with said first and second fixed electrodes and is attached to the upper wall of said external conductor so that an insertion length of said movable electrode into said first metal hollow cylinder can be varied;
• an input terminal having an inner conductor;
• an output terminal having an inner conductor;
• and
• means provided in said circumferential space for connecting said second fixed electrode to the top resonance capacity element of said plurality of resonance capacity elements to said inner conductor of said input terminal;
• means provided in said circumferential space for connecting said second fixed electrode of the last resonance capacity element of said plurality of resonance capacity elements to said inner conductor of said output terminal in a high-frequency fashion.