High quality factor (Q) planar spiral inductor based CATV diplexer and telephony module

• US 20030186674A1
• Filed: 03/29/2002
• Published: 10/02/2003
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: MACOM Technology Solutions Holdings, Inc.
• Original Assignee: M/A Com
• Inventors: Wallace, Deirdre Anne, Keeney, Bill Allen
• Granted Patent: US 6,894,585 B2
• Time in Patent Office: Days
• US Class Current: 455/347
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets inside PCB filters H05K
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/0123 comprising distributed impedance elements together with lumped impedance elements
• CPC Class Codes: H03H 7/48 Networks for connecting several sources or loads, working on the same frequency or frequency band, to a common load or source phase shifters providing two or more output signals H03H7/21
• CPC Class Codes: H05K 1/0231 Capacitors or dielectric substances
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/09181 Notches in edge pads
• CPC Class Codes: H05K 2201/1006 Non-printed filter
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/3442 having edge contacts, e.g. leadless chip capacitors, chip carriers
• CPC Class Codes: H05K 3/403 Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof H05K3/4092 takes precedence
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

A cable television diplexer and telephony module that can be employed in CATV data transmission systems to enhance performance levels and reduce manufacturing costs. The cable television diplexer and telephony module includes a printed circuit board substrate, and a diplexer having a low pass filter section and a high pass filter section, each of which has components mounted on the substrate. The respective low pass and high pass filter sections of the diplexer include one or more high Q value planar spiral inductors. Each spiral inductor includes a narrow track of metal disposed on the substrate and wound around a center to form a circular spiral curve having a plurality of turns. The spiral inductor may be fabricated on the substrate of the cable television diplexer and telephony module, or on a separate substrate, using a standard PCB fabrication process.

Claims

1. A radio frequency input/output module, comprising:

a first printed circuit board substrate; and

filter circuitry disposed on the first substrate and configured to receive at least one radio frequency input signal and transmit at least one radio frequency output signal, the filter circuitry including at least one high quality factor value inductor,

wherein the high quality factor value inductor comprises a planar circular spiral inductor fabricatable using a standard printed circuit board fabrication process.

2. The radio frequency input/output module of claim 1 wherein the high quality factor value inductor is implemented on the first substrate during a fabrication process of the first substrate.

3. The radio frequency input/output module of claim 1 wherein the high quality factor value inductor is implemented on a second printed circuit board substrate separate from the first substrate during a fabrication process of the second substrate.

4. The radio frequency input/output module of claim 3 wherein the first substrate includes at least one hole and the high quality factor value inductor is disposed on the first substrate such that the inductor is in registration with the hole.

5. The radio frequency input/output module of claim 1 wherein the high quality factor value inductor includes at least one narrow track of metal disposed on at least one side of the first substrate.

6. The radio frequency input/output module of claim 5 wherein the narrow track of metal of the inductor is wound around a center via to form a circular spiral curve having a plurality of turns.

7. The radio frequency input/output module of claim 6 wherein the track of metal is disposed on a first side of the first substrate, the track of metal having an inner end connected to the center via, and wherein the center via is configured to allow electrical connection to the inner end of the metal track from a second side of the first substrate.

8. The radio frequency input/output module of claim 7 wherein the track of metal further has an outer end, the outer end being connected to a second via, and wherein the second via is configured to allow electrical connection to the outer end of the metal track from the first side or the second side of the first substrate.

9. A high quality factor value inductor, the inductor being monolithically implementable on a printed circuit board substrate, comprising:

at least one narrow track of metal disposed on at least one side of the substrate,

wherein the narrow track of metal is wound around a center to form a circular spiral curve having a plurality of turns, thereby reducing stray capacitance between the inductor and the substrate.

10. The high quality factor value inductor of claim 9 wherein the track of metal is disposed on a first side of the substrate, the track of metal having an inner end connected to a center via, and wherein the center via is configured to allow electrical connection to the inner end of the metal track from a second side of the substrate.

11. The high quality factor value inductor of claim 10 wherein the track of metal further has an outer end, the outer end being connected to a second via, and wherein the second via is configured to allow electrical connection to the outer end of the metal track from the first side or the second side of the substrate.

12. The high quality factor value inductor of claim 9 wherein the inductor is implemented on the substrate during a fabrication process of the substrate.

13. A method of fabricating a radio frequency input/output module including one or more spiral inductors, comprising the steps of:

fabricating a first printed circuit board substrate according to a predetermined layout of the radio frequency input/output module; and

during the fabrication of the first substrate, implementing at least one first spiral inductor on the first substrate, the first spiral inductor comprising at least one narrow track of metal disposed on at least one side of the first substrate, the narrow track of metal being wound around a center to form a circular spiral curve having a plurality of turns, thereby reducing stray capacitance between the inductor and the first substrate.

14. The method of claim 13 further including the steps of:

forming a plurality of holes at predetermined locations through the first substrate, each hole having a predetermined radius;

fabricating a second printed circuit board substrate to implement at least one second circular spiral inductor, each second spiral inductor having an outer radius approximately equal to the hole radius;

separating the second spiral inductor from the second substrate; and

positioning the second spiral inductor on the first substrate so that the second spiral inductor is in registration with the respective hole formed through the first substrate.

15. The method of claim 13 wherein the step of fabricating the first substrate includes fabricating the first substrate using a standard printed circuit board fabrication process.