Ceramic filter having integral phase shifting network

• US 4,896,124 A
• Filed: 10/31/1988
• Issued: 01/23/1990
• Est. Priority Date: 10/31/1988
• Status: Expired due to Term

• Current Assignee: Murray, Inc. (Briggs & Stratton Corporation)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Schwent, Dale G.
• Primary Examiner(s): Nussbaum, Marvin L.
• Application Number:
  US07/264,659
• Time in Patent Office: 449 Days
• Field of Search: 333/202, 333/203, 333/206-212, 333/219, 333/222-223, 333/227-228, 333/230-231, 333/156-161, 333/132-135, 333/138-139, 333/140, 455/73, 455/78-83
• 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

An integral phase shifting network of a transmitter filter provides a means to reduce the size and increase the efficiency of an antenna coupling network. The network to shift the phase of the transmitter filter is printed by depositing conductive material directly on a ceramic block using low-loss circuit elements and can be tuned easily by removing conductive material if required in certain applications. By utilizing an integral phase shifting network, either transmit or receive filters having a higly reactive and capacitive out-of-band impedance in the receive or transmit band, respectively, can be connected to a common antenna port without external transmission lines.

Claims

1. A filter for filtering radio signals, comprising:

dielectric means comprised of a dielectric filter having top, bottom and side surfaces, said bottom and side surfaces being substantially covered with a conductive material, a plurality of holes each having surfaces substantially covered by a conductive material and extending from the top surface toward the second surface;

input coupling means coupled to a first hole of said plurality of holes;

first electrode means disposed on the top surface of said dielectric means and coupled to the conductive material of a second of said plurality of holes;

second electrode means disposed on the top surface of said dielectric means at a predetermined distance from said first electrode means for capacitively coupling thereto;

first transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end coupled to the conductive material of one of said side surfaces, for producing a predetermined inductive impedance;

second transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end disposed at a predetermined distance from the conductive material of one of said sides, for producing a predetermined capacitive impedance; and

output coupling means coupled to the first end of said second transmission line means.

2. The filter according to claim 1, wherein said output coupling means comprises third transmission line means disposed on the top surface of said dielectric means and having a first end coupled to the first end of said second transmission line means and having a portion thereof and a second end disposed on one of said side surfaces.

3. The filter according to claim 1, further including fourth transmission line means disposed on the top surface of said dielectric means between said second electrode means and said second transmission line means, said fourth transmission line means having a first end coupled to said second electrode means and having a second end coupled to the first end of said second transmission line means and said output coupling means.

4. A filter for filtering radio signals, comprising:

a block comprised of a ceramic having top, bottom and side surfaces, said bottom and side surfaces being substantially covered with a conductive material, a plurality of holes each having surfaces substantially covered by a conductive material and extending from the top surface toward the second surface;

input coupling means coupled to a first hole of said plurality of holes;

first electrode means comprised of a conductive material disposed on the top surface of said block and coupled to the conductive material of a second of said plurality of holes;

second electrode means comprised of a conductive material disposed on the top surface of said block at a predetermined distance from said first electrode means for capacitively coupling thereto;

first transmission line means comprised of a conductive material disposed on the top surface of said block and having a first end coupled to said second electrode means and having a second end coupled to the conductive material of one of said side surfaces, for producing a predetermined inductive impedance;

second transmission line means comprised of a conductive material disposed on the top surface of said block and having a first and coupled to said second electrode means and having a second end;

third transmission line means comprised of a conductive material disposed on the top surface of said block and having a first end coupled to the second end of said second transmission line means and having a second end disposed at a predetermined distance from the conductive material of one of said sides, for producing a predetermined capacitive impedance; and

output coupling means coupled to the second end of said second transmission line means.

5. The filter according to claim 4, wherein said output coupling means comprises fourth transmission line means comprised of a conductive material disposed on the top surface of said block and having a first end coupled to the second end of said second transmission line means and having a portion thereof and a second end disposed on one of said side surfaces.

6. A duplexing network for coupling first and second signals to an antenna comprising in combination:

an antenna transmission line having a first end coupled to said antenna and having a second end;

first transmission line means having a first end coupled to the first signal and having a second end coupled to the second end of the antenna transmission line;

a filter comprising;

dielectric means comprised of a dielectric filter having top, bottom and side surfaces, said bottom and side surfaces being substantially covered with a conductive material, a plurality of holes each having surfaces substantially covered by a conductive material and extending from the top surface toward the second surface;

input coupling means for coupling the second signal to a first hole of said plurality of holes;

first electrode means disposed on the top surface of said dielectric means and coupled to the conductive material of a second of said plurality of holes;

second electrode means disposed on the top surface of said dielectric means at a predetermined distance from said first electrode means for capacitively coupling thereto;

second transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end coupled to the conductive material of one of said side surfaces, for producing a predetermined inductive impedance;

third transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end;

fourth transmission line means disposed on the top surface of said dielectric means and having a first end coupled to the second end of said third transmission line means and having a second end disposed at a predetermined distance from the conductive material of one of said sides, for producing a predetermined capacitive impedance; and

output coupling means for coupling the second end of said antenna transmission line to the second end of said third transmission line means.

7. The duplexing network according to claim 6, wherein said output coupling means comprises fifth transmission line means disposed on the top surface of said dielectric means and having a first end coupled to the second end of said second transmission line means and having a portion thereof and a second end disposed on one of said side surfaces.

8. A radio comprising in combination:

an antenna;

an antenna transmission line having a first end coupled to said antenna and having a second end;

a receiver having an input;

a receive transmission line having a first end coupled to the input of the receiver and having a second end coupled to the second end of the antenna transmission line;

a transmitter having an output;

a transmit filter comprising;

dielectric means comprised of a dielectric filter having top, bottom and side surfaces, said bottom and side surfaces being substantially covered with a conductive material, a plurality of holes each having surfaces substantially covered by a conductive material and extending from the top surface toward the second surface;

input coupling means for coupling the output of said transmitter to a first hole of said plurality of holes;

first electrode means disposed on the top surface of said dielectric means and coupled to the conductive material of a second of said plurality of holes;

second electrode means disposed on the top surface of said dielectric means at a predetermined distance from said first electrode means for capacitively coupling thereto;

first transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end coupled to the conductive material of one of said side surfaces, for producing a predetermined inductive impedance;

second transmission line means disposed on the top surface of said dielectric means and having a first end coupled to said second electrode means and having a second end;

third transmission line means disposed on the top surface of said dielectric means and having a first end coupled to the second end of said second transmission line means and having a second end disposed at a predetermined distance from the conductive material of one of said sides, for producing a predetermined capacitive impedance; and

output coupling means for coupling the second end of said antenna transmission line to the second end of said second transmission line means.

9. The radio according to claim 8, wherein said output coupling means comprises fourth transmission line means disposed on the top surface of said dielectric means and having a first end coupled to the second end of said first transmission line means and having a portion thereof and a second end disposed on one of said side surfaces.