Delay filter module

• US 20080204165A1
• Filed: 02/13/2008
• Published: 08/28/2008
• Est. Priority Date: 02/22/2007
• Status: Active Grant

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Vangala, Reddy R.
• Granted Patent: US 7,928,816 B2
• Time in Patent Office: Days
• US Class Current: 333/156
• CPC Class Codes: H01P 1/205 Comb or interdigital filters; Cascaded coaxial cavities H01P1/203 takes precedence
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H05K 1/0243 Printed circuits associated with mounted high frequency components
• CPC Class Codes: H05K 2201/09336 Signal conductors in same plane as power plane
• CPC Class Codes: H05K 2201/1006 Non-printed filter
• CPC Class Codes: H05K 2201/10969 Metallic case or integral heatsink of component electrically connected to a pad on PCB
• CPC Class Codes: H05K 3/3442 having edge contacts, e.g. leadless chip capacitors, chip carriers

Abstract

A delay filter module comprising at least one dielectric monoblock ceramic bandpass filter and a circuit for compensating/equalizing the signal delay produced by the delay filter. In one embodiment, the circuit is defined by a hybrid coupler defining at least two ports coupled to a dielectric ceramic reactive termination block defining at least a pair of reactive termination resonators and coupling capacitors. The delay can be adjusted by tuning the dielectric monoblock bandpass filter and/or the reactive termination resonators and/or the coupling capacitors defined by the dielectric ceramic reactive termination block.

Claims

1. A delay filter module comprising:

a printed circuit board defining at least respective RF signal input/output transmission lines;

a dielectric monoblock bandpass filter mounted on the printed circuit board and adapted to provide and pass a delayed and filtered RF signal through the module, the filter defining at least two resonators and at least two RF signal input/output ports;

a circuit for compensating the delay in the RF signal passing through the dielectric monoblock bandpass filter, the circuit including;

a hybrid coupler mounted on the printed circuit board and defining at least four RF signal input/output ports; and

at least two dielectric reactive termination resonators on the printed circuit board, the resonators coupled respectively to two of the ports defined on said coupler and including at least two coupling capacitors;

wherein the other two of the ports on said coupler are respectively coupled to one of the ports of said dielectric monoblock filter and one of said RF signal input/output lines defined on said printed circuit board, the other of said RF signal input/output lines defined on said printed circuit board being coupled to the other of said RF signal input/output ports defined on said dielectric monoblock bandpass filter.

2. The delay filter module of claim 1 further comprising a dielectric reactive termination block mounted on said printed circuit board and defining said at least two dielectric resonators and associated coupling capacitors of said circuit.

3. A method of adjusting the delay produced by the dielectric monoblock bandpass filter of the delay line filter module of claim 2 comprising the steps of tuning the dielectric monoblock bandpass filter and/or the reactive termination resonators and/or the coupling capacitors.

4. The delay filter module of claim 2 wherein the dielectric monoblock bandpass filter and dielectric reactive termination block are both of ceramic monoblock construction.

5. A delay filter module comprising:

a printed circuit board defining an RF signal input transmission line and an RF signal output transmission line;

a dielectric monoblock bandpass filter of ceramic construction mounted on the printed circuit board and adapted to pass a delayed and filtered RF signal through the delay line filter module, one of said RF signal input or output transmission lines being coupled to said dielectric monoblock bandpass filter;

a coupler mounted on the printed circuit board, the other of said RF signal input or output transmission lines being coupled to said coupler;

a dielectric reactive termination monoblock of ceramic construction; and

a plurality of additional RF signal transmission lines defined on said printed circuit board, the additional RF signal transmission lines interconnecting said coupler to said dielectric reactive termination monoblock and said coupler to said dielectric monoblock bandpass filter and defining a circuit for compensating the delay in the RF signal passing through said dielectric monoblock bandpass filter.

6. The delay filter module of claim 5 wherein the dielectric monoblock bandpass filter and dielectric reactive termination monoblock each define at least first and second resonators.

7. The delay filter module of claim 6 wherein each of the first and second resonators defined by said dielectric reactive termination monoblock defines a coupling capacitor, a shunt capacitor, and a short-circuited transmission line.

8. The delay filter module of claim 5 wherein the dielectric monoblock bandpass filter, the coupler, and the dielectric reactive termination monoblock are mounted on the printed circuit board in a generally parallel and spaced-apart relationship, the coupler being located between the dielectric monoblock bandpass filter and the dielectric reactive termination monoblock.

9. A method of tuning the ripple in the delay produced by a dielectric monoblock bandpass filter of a delay filter module comprising said dielectric monoblock bandpass filter, a hybrid coupler, and at least two dielectric reactive termination resonators defining respective coupling capacitors, the method comprising the steps of:

a) tuning the dielectric monoblock bandpass filter; and

/or

b) tuning the center frequency of one or both of said dielectric reactive termination resonators; and

/or

c) tuning one or both of said coupling capacitors defined by said dielectric reactive termination resonators.

10. The method of claim 9 wherein said dielectric reactive termination resonators are defined on a dielectric reactive termination monoblock, the reactive termination monoblock and dielectric monoblock bandpass filter both being of ceramic construction.