Radiofrequency (RF) filter for multi-frequency RF bias

Patent metadata

Field	Value
Publication number	US-10715095-B2
Application number	US-201715727516-A
Country	US
Kind code	B2
Filing date	Oct 6, 2017
Priority date	Oct 6, 2017
Publication date	Jul 14, 2020
Grant date	Jul 14, 2020

Abstract

A radiofrequency (RF) filter includes an inductive element having multiple coil sections collectively forming an undivided coil of a cable of twisted magnetic wires. At least two adjacent coil sections have different turn pitches. The cable of twisted magnetic wires includes two wires per channel and is configured for at least one channel. The cable of twisted magnetic wires at a first end of the inductive element is configured for connection to an electrical component that is to receive power from a power supply. The cable of twisted magnetic wires at a second end of the inductive element is configured for connection to the power supply. Terminating capacitive elements are electrically connected between a reference ground potential and a respective wire of the cable of twisted magnetic wires at respective locations between the second end of the inductive element and the power supply.

First claim

What is claimed is:

1. A radiofrequency (RF) filter, comprising:
an inductive element including a coil form and at least two coil sections collectively forming an undivided coil of a cable of twisted magnetic wires wrapped around the coil form, the coil form being a hollow cylinder having an inner diameter and an outer diameter, the inner diameter of the coil form defined to provide for cooling air flow through the coil form, each coil section including a portion of the undivided coil of the cable of twisted magnetic wires configured at a corresponding turn pitch, at least two adjacent coil sections having different turn pitches, the cable of twisted magnetic wires including two wires per channel and configured for at least one channel, the cable of twisted magnetic wires at a first end of the inductive element configured for connection to an electrical component that is to receive power from a power supply, the cable of twisted magnetic wires at a second end of the inductive element configured for connection to the power supply;
a set of terminating capacitive elements including a separate terminating capacitive element for each wire of the cable of twisted magnetic wires, each terminating capacitive element electrically connected between a reference ground potential and a respective wire of the cable of twisted magnetic wires at a location between the second end of the inductive element and the power supply; and
a fan positioned at an end of the coil form to move cooling air through the coil form.

2. The RF filter as recited in claim 1 , wherein the undivided coil of the cable of twisted magnetic wires has a continuous configuration through each transition between adjacent ones of the at least two coil sections.

3. The RF filter as recited in claim 1 , wherein the at least two coil sections are associated with corresponding RF frequencies to be filtered by the RF filter.

4. The RF filter as recited in claim 3 , wherein the turn pitch of a given coil section is set to make the given coil section resonant with one of the corresponding RF frequencies to be filtered by the RF filter.

5. The RF filter as recited in claim 1 , wherein each wire of the cable of twisted magnetic wires is an electrical conductor coated with an electrical insulating coating material.

6. The RF filter as recited in claim 5 , wherein the electrical insulating coating material prevents wire-to-wire conduction of low frequency electrical current and allows wire-to-wire transmission of RF power.

7. The RF filter as recited in claim 1 , wherein at least one coil section includes a plurality of turn layers of the cable of twisted magnetic wires, the plurality of turn layers stacked in a radial direction relative to an axis of the inductive element.

8. The RF filter as recited in claim 1 , wherein at least two coil sections have different lengths as measured along an axis of the inductive element.

9. The RF filter as recited in claim 1 , wherein the undivided coil of the cable of twisted magnetic wires has a different turn diameter in at least two coil sections.

10. The RF filter as recited in claim 1 , wherein the undivided coil of the cable of twisted magnetic wires has a different turn shape in at least two coil sections.

11. The RF filter as recited in claim 1 , wherein the cable of twisted magnetic wires includes eight wires and is configured for four channels, and the number of the at least two coil sections is two.

12. The RF filter as recited in claim 1 , wherein the undivided coil of the cable of twisted magnetic wires has a substantially same turn diameter in the at least two coil sections, the turn pitch of a first coil section that connects to the first end of the inductive element being larger that the turn pitch of a second coil section that connects to the second end of the inductive element.

13. The RF filter as recited in claim 12 , wherein the first coil section has a single turn layer of the cable of twisted magnetic wires and the second coil section has two turn layers of the cable of twisted magnetic wires.

14. The RF filter as recited in claim 13 , wherein the first coil section has about 13 turns of the cable of twisted magnetic wires within the single turn layer, and the second coil section has about 21 turns of the cable of twisted magnetic wires within an inner turn layer of the two turn layers, and the second coil section has about 18 turns of the cable of twisted magnetic wires within an outer turn layer of the two turn layers, and each terminating capacitive element in the set of terminating capacitive elements having a capacitance value of about 0.1 microFarad.

15. The RF filter as recited in claim 1 , wherein a continuous groove is formed within an outer surface of the coil form, the continuous groove configured to receive the cable of twisted magnetic wires and preserve a spatial configuration of the undivided coil of the cable of twisted magnetic wires.

16. A method for filtering radiofrequency (RF) power, comprising:
having an RF filter between a power supply and an electrical component that is to receive power from the power supply, the RF filter including an inductive element having a coil form and at least two coil sections collectively forming an undivided coil of a cable of twisted magnetic wires wrapped around the coil form, the coil form being a hollow cylinder having an inner diameter and an outer diameter, the inner diameter of the coil form defined to provide for cooling air flow through the coil form, each coil section including a portion of the undivided coil of the cable of twisted magnetic wires configured at a corresponding turn pitch, at least two adjacent coil sections having different turn pitches, the cable of twisted magnetic wires including two wires per channel and configured for at least one channel, the cable of twisted magnetic wires at a first end of the inductive element connected to the electrical component, the cable of twisted magnetic wires at a second end of the inductive element connected to the power supply, the RF filter including a separate terminating capacitive element for each wire of the cable of twisted magnetic wires, each terminating capacitive element electrically connected between a reference ground potential and a respective wire of the cable of twisted magnetic wires at a location between the second end of the inductive element and the power supply; and
operating a fan positioned at an end of the coil form to move cooling air through the coil form.

17. The method for filtering RF power as recited in claim 16 , wherein a number of the at least two coil sections corresponds to a number of different RF frequencies to be filtered, and wherein the turn pitch of a given coil section is set to make the given coil section resonant with one of the number of different RF frequencies to be filtered.

18. The method for filtering RF power as recited in claim 17 , wherein each wire of the cable of twisted magnetic wires is an electrical conductor coated with an electrical insulating coating material that prevents wire-to-wire conduction of low frequency electrical current and allows wire-to-wire transmission of RF power.

19. A method for filtering radiofrequency (RF) power, comprising:
transmitting electrical power from a power supply to wires within an input arrangement, the wires connected to respective capacitive elements, each separate pair of the wires designated to provide electrical power to an electrical component that is exposed to RF power;
passing electrical power from the wires within the input arrangement

Assignees

• Lam Res Corp

Inventors

• Long Maolin
• Paterson Alex

Classifications

• H05B6/664 Primary

  Aspects related to the power supply of the microwave heating apparatus · CPC title

• H03H7/0115

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H01J37/32082

  Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence) · CPC title

• H01F30/00 Primary

  Fixed transformers not covered by group H01F19/00 · CPC title

• H01F27/28

  Coils; Windings; Conductive connections · CPC title