Variable radio frequency band filter

• US 20070247262A1
• Filed: 04/13/2007
• Published: 10/25/2007
• Est. Priority Date: 08/23/2003
• Status: Active Grant

• Current Assignee: KMW Incorporated
• Original Assignee: KMW Incorporated
• Inventors: Kim, Jae-Hong, Kim, Byung-Chul, Kim, Duk-Yong, Lee, Gil-Ho, Kim, Kwang-Yeob, Park, Jong-Kyu, Kim, Yon-Tae
• Granted Patent: US 7,449,981 B2
• Time in Patent Office: Days
• US Class Current: 333/202
• CPC Class Codes: H01P 1/205 Comb or interdigital filters; Cascaded coaxial cavities H01P1/203 takes precedence
• CPC Class Codes: H01P 1/2053 the coaxial cavity resonators being disposed parall to each other

Abstract

A variable radio frequency band filter capable of varying the resonance frequency band comprises a housing having a support; a number of resonator rods arranged along the longitudinal direction of the housing; at least one tuning rod positioned on top of the resonator rods; a tuning support extending through the respective tuning rods along the longitudinal direction of the housing and adapted to slide on top of the respective resonator rods to vary the position of the tuning rods; and a frequency variation unit positioned on a lateral surface of the housing. The frequency variation unit being coupled to an end of the tuning support and adapted to vary the position of the tuning rods, as the tuning support is slid, according to the frequency band.

Claims

1. A variable frequency band filter comprising:

a housing;

a number of resonator rods extending upward from the internal bottom surface of the housing;

tuning plates positioned on the internal top surface of the housing and facing the upper end surface of the respective resonator rods;

a tuning support rotatably coupled on the housing and positioned on top of the tuning plates; and

tuning bars coupled to the tuning support and adapted to cause the tuning plates to approach or move away from the resonator rods as the tuning support is rotated.

2. A variable frequency band filter as claimed in claim 1, further comprising at least one pair of support base protruding from the upper surface of the housing and having a through-hole extending along the longitudinal direction of the housing to rotatably support the tuning support.

3. A variable frequency band filter as claimed in claim 2, wherein a pair of support bases, which constitute a set, are positioned in such a manner that they correspond to each of the resonator rods, and a tuning hole is formed on the housing between the pair of support bases, which constitute a set, so that the tuning bars can pass through the tuning hole.

4. A variable frequency band filter as claimed in claim 3, further comprising a tuning screw positioned adjacently to the pair of support bases, which constitute a set, and used for fine tuning of the resonance frequency.

5. A variable frequency band filter as claimed in claim 1, further comprising an adjustment knob positioned on an end of the tuning support to rotate the tuning support.

6. A variable frequency band filter as claimed in claim 1, further comprising fixation nuts coupled to the tuning support and positioned adjacently to the support bases.

7. A variable frequency band filter comprising:

a housing;

at least one resonator rod extending from the bottom surface of the housing;

a tuning screw bar fastened to the outer peripheral surface of the housing and having an end disposed adjacently to the resonator rod; and

a tuning support rotatably coupled to the outer peripheral surface of the housing to move the tuning screw bar, wherein

as the tuning support is rotated, the tuning screw bar is moved and the resonance frequency band is varied.

8. A variable frequency band filter as claimed in claim 7, wherein the tuning screw bar is fastened on the tuning support;

the tuning support is positioned on the upper surface of the housing;

said filter further comprises a semi-spherical tuning disk having a planar surface, fastened to an end of the tuning screw bar, and a curved surface, facing the upper surface of the resonator rod; and

, as the tuning screw bar is moved, the area of the tuning disk facing the resonator rod and the distance between them are adjusted.

9. A variable frequency band filter as claimed in claim 7, wherein the tuning screw bar is fastened on the tuning support;

the tuning support is positioned on a lateral surface of the housing;

said filter further comprises a tuning plate coupled to an end of the tuning screw bar and facing the upper surface of the resonator rod; and

, as the tuning screw bar is moved, the area of the tuning plate facing the resonator rod and the distance between them are adjusted.

10. A variable frequency band filter as claimed in claim 7, wherein the tuning screw bar and the tuning support are positioned adjacently to each other on the upper surface of the housing;

said filter further comprises a tuning gear, which is coupled to the outer peripheral surface of an end of the tuning screw bar and which has gear teeth formed along the circumferential direction with a constant spacing, and a tuning support gear formed on the outer peripheral surface of the tuning support to be engaged with the tuning gear; and

, as the tuning support is rotated, the tuning gear is rotated and moves the tuning screw bar along the longitudinal direction, thereby adjusting the distance to the resonator rod.

11. A variable frequency band filter as claimed in claim 10, further comprising a tension nut fastened to the upper surface of the housing and having a slot formed along the longitudinal direction to press the outer peripheral surface of the tuning screw bar.

12. A variable frequency band filter as claimed in claim 7, wherein at least one pair of resonator rods are positioned along the longitudinal direction of the housing with a constant spacing, at least one pair of support base are positioned on the outer peripheral surface of the housing with a constant spacing, and the tuning support is rotatably coupled to the support bases.

13. A variable frequency band filter as claimed in claim 12, further comprising a tuning support guide interposed between the outer peripheral surface of the tuning support and the support bases to provide lubrication as the tuning support is rotated.

14. A variable frequency band filter as claimed in claim 7, wherein the housing is divided into at least two containing spaces by diaphragms formed therein, and the resonator rods are contained in the respective containing spaces.

15. A variable frequency band filter as claimed in claim 14, wherein the containing spaces are connected in series through coupling windows formed on the diaphragms.

16. A variable frequency band filter as claimed in claim 15, further comprising coupling tuning screws fastened to the upper surface of the housing and positioned in such a manner that they face the corresponding coupling windows.

17. A variable frequency band filter as claimed in claim 7, wherein the tuning support has a knob formed on an end thereof to rotate the tuning support.

18. A variable frequency band filter comprising:

a housing;

at least one resonator rod extending from the bottom surface of the housing;

a first resonance tuning screw coupled to the outer peripheral surface of the housing in such a manner that the first resonance tuning screw can be moved linearly, an end of the first resonance tuning screw being disposed adjacently to the resonator rod;

a tuning support rotatably coupled to the outer peripheral surface of the housing;

a support plate extending from the outer peripheral surface of the tuning support, the support plate having a surface facing the other end of the first resonance tuning screw and being adapted to be rotated about the tuning support, as the tuning support is rotated; and

a support spring having an end supported on the outer peripheral surface of the housing and the other end supported on the other end of the first resonance tuning screw, the supporting spring providing an elastic force in such a direction that an end of the first resonance tuning screw is moved away from the resonator rod, wherein

as the tuning support is rotated in one direction, an end of the first resonance tuning screw is moved by the support plate in a direction approaching the resonator rod, and as the tuning support is rotated in the other direction, an end of the first resonance tuning screw is moved away from the resonator rod, thereby varying the resonance frequency band.

19. Variable frequency band filter as claimed in claim 18, further comprising a second resonance tuning screw fastened to the support plate and having an end contacting a surface of the other end of the first resonance tuning screw.

20. Variable frequency band filter as claimed in claim 19, wherein the end of the second resonance tuning screw, which contacts the surface of the other end of the first resonance tuning screw, has a curved surface so that, even when the tuning support is rotated, the area of the first resonance tuning screw contacting the second resonance tuning screw is maintained constant.

21. Variable frequency band filter as claimed in claim 18, further comprising at least one support base fixed on the outer peripheral surface of the housing to support the rotation of the tuning support.

22. Variable frequency band filter as claimed in claim 18, further comprising a tension nut fastened on the housing to guide the linear reciprocating movement of the first resonance tuning screw.

23. Variable frequency band filter as claimed in claim 18, wherein the support plate has an end contacting the outer peripheral surface of the tuning support and is fastened to the tuning support by a screw, which extends through the tuning support in the diametric direction.

24. Variable frequency band filter as claimed in claim 18, wherein the support plate integrally extends from the outer peripheral surface of the tuning support.