Monolithic ceramic filter with bandstop function

• US 4,823,098 A
• Filed: 06/14/1988
• Issued: 04/18/1989
• Est. Priority Date: 06/14/1988
• Status: Expired due to Term

• Current Assignee: CTS Corporation
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: DeMuro, David M., Agahi-Kesheh, Darioush
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/206,384
• Time in Patent Office: 308 Days
• Field of Search: 333/202, 333/206, 333/207, 333/204, 333/205, 333/222, 333/223, 333/219, 333/219.1, 333/208-212, 333/245, 333/235, 333/132, 333/134, 333/135, 333/136, 455/78, 455/82-83
• US Class Current: 333/206
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H01P 1/2136 using comb or interdigital filters; using cascaded coaxial cavities H01P1/2131, H01P1/2135 take precedence

Abstract

A ceramic filter includes a multiple zero bandstop filter function. The ceramic filter has a dielectric block with top and bottom surfaces and at least two holes, including a first hole and a second hole, extending from the top surface toward the bottom surface of the block. The block is selectively covered with a conductive material to provide a transmission line resonator for each of the two holes. The filter also includes an input electrode coupled to the dielectric means at a predetermined distance from the first hole, and an output electrode coupled to the dielectric means at a predetermined distance from the second hole. Finally, conductive plating, in the form of a transmission line, is contiguously disposed on the dielectric means adjacent the two holes and coupled thereto to provide a bandstop filter function with a zero represented at each hole.

Claims

1. A filter comprising:

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least two holes, including a first hole and a second hole with no intervening holes therebetween, extending from the top surface toward the bottom surface thereof and spatially disposed at a predetermined distance from one another, said dielectric means selectively covered with a conductive material to provide a transmission line resonator for each of said at least two holes;

input electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole in dielectric means;

output electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said second hole in the dielectric means; and

plating line means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function.

2. A filter, according to claim 1, wherein said at least two holes include a surface covered with conductive plating.

3. A filter, according to claim 1, wherein said dielectric means includes portions of conductive plating surrounding said at least two holes.

4. A filter, according to claim 3, wherein said plating line means is disposed a predetermined distances from said portions of conductive plating.

5. A filter, according to claim 1, wherein said input electrode means is part of said plating line means.

6. A filter, according to claim 1, wherein said output electrode means is part of said plating line means.

7. A filter, according to claim 1, wherein said plating line means includes at least one impedance inverter means.

8. A filter, according to claim 1, wherein said plating line means includes at least one quarter wavelength transmission line.

9. A filter comprising:

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least three holes extending from the top surface toward the bottom surface thereof, said three holes including;

a first hole and a second hole wherein the first hole is spatially disposed at a predetermined distance from the second hole without any intervening holes therebetween, and

a third hole spatially disposed at a predetermined distance from the second hole;

conductive material selectively covering said dielectric means to provide a transmission line resonator for each of said at least three holes;

electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole of said first, second and third holes;

electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said third hole of said first, second and third holes; and

impedance inverter plating means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function.

10. A filter, according to claim 9, wherein said impedance inverter plating means includes at least on quarter wave length transmission line.

11. A filter, according to claim 10, wherein said quarter wave length transmission line includes a non-lineal conductive plating segment.

12. A filter, according to claim 9, wherein said third hole provides a bandpass filter function within the filter.

13. An RF transceiver comprising:

a transmitter;

a receiver;

an antenna;

first filter means coupled between said transmitter and said antenna;

second filter means coupled between said receiver and said antenna;

at least one of said first filter means and said second filter means including;

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least two holes, including a first hole and a second hole with no intervening holes therebetween, extending from the top surface toward the bottom surface thereof and spatially disposed at a predetermined distance from one another, said dielectric means selectively covered with a conductive material to provide a transmission line resonator for each of said at least two holes,

input electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole in the dielectric means,

output electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said second hole in the dielectric means, and

plating line means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function.

14. A duplexer for coupling a transceiver to an antenna, comprising:

first filter means, having an input stage coupled to the antenna and an output stage coupled to the transceiver, for selecting signals applied thereto;

said first filter means further comprising;

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least two holes, including a first hole and a second hole with no intervening holes therebetween, extending from the top surface toward the bottom surface thereof and spatially disposed at a predetermined distance from one another, said dielectric means selectively covered with a conductive material to provide a transmission line resonator for each of said at least two holes;

input electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole in dielectric means;

output electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said second hole in the dielectric means; and

plating line means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function; and

second filter means, having an input stage coupled to the transceiver and an output stage coupled to the antenna, for selecting signals applied thereto.

15. A duplexer for coupling a transceiver to an antenna, comprising:

first filter means, having an input stage coupled to the antenna and an output stage coupled to the transceiver, for selecting signals applied thereto; and

second filter means, having an input stage coupled to the transceiver and an output stage coupled to the antenna, for selecting signals applied thereto;

said first filter means further comprising;

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least two holes, including a first hole and a second hole with no intervening holes therebetween, extending from the top surface toward the bottom surface thereof and spatially disposed at a predetermined distance from one another, said dielectric means selectively covered with a conductive material to provide a transmission line resonator for each of said at least two holes;

input electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole in dielectric means;

output electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said second hole in the dielectric means; and

plating line means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function.

16. A bandstop filter comprising:

dielectric means comprised of a dielectric material having top and bottom surfaces, said dielectric means further having at least two holes, including a first hole and a second hole with no intervening holes therebetween, extending from the top surface toward the bottom surface thereof and spatially disposed at a predetermined distance from one another, said dielectric means selectively covered with a conductive material to provide a transmission line resonator for each of said at least two holes;

input electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said first hole in dielectric means;

output electrode means comprised of a conductive material coupled to the dielectric means at a predetermined distance from said second hole in the dielectric means; and

plating line means comprised of a conductive material contiguously disposed on the dielectric means adjacent said first hole and said second hole and coupled thereto to provide a bandstop filter function.