Method for compensating a temperature drift of a microwave filter

Patent metadata

Field	Value
Publication number	US-10199704-B2
Application number	US-201515115604-A
Country	US
Kind code	B2
Filing date	Jan 19, 2015
Priority date	Jan 31, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A method for compensating a temperature drift of a microwave filter comprises: measuring a first frequency response of a microwave filter at a first temperature; determining values of elements of an equivalent circuit corresponding to the microwave filter such that a first modelled frequency response computed using the equivalent circuit matches the first measured frequency response to obtain a first model modelling the microwave filter at the first temperature: measuring a second frequency response of the microwave filter at a second temperature; determining values of elements of the equivalent circuit corresponding to the microwave filter anew such that a second modelled frequency response computed using the equivalent circuit matches the second measured frequency response to obtain a second model modelling the microwave filter at the second temperature; and adjusting an overall temperature drift of the microwave filter to adjust the temperature drifts of the resonant filter elements.

First claim

The invention claimed is:

1. A method for compensating a temperature drift of a microwave filter, the method comprising:
measuring a first frequency response of the microwave filter comprising multiple resonant filter elements at a first temperature to obtain a first measured frequency response,
adjusting model elements in an equivalent circuit corresponding to the microwave filter such that a first modelled frequency response computed using the equivalent circuit matches the first measured frequency response to obtain a first model modelling the microwave filter at the first temperature,
measuring a second frequency response of the microwave filter at a second temperature to obtain a second measured frequency response,
adjusting the model elements in the equivalent circuit corresponding to the microwave filter such that a second modelled frequency response computed using the equivalent circuit matches the second measured frequency response to obtain a second model modelling the microwave filter at the second temperature,
determining a temperature drift of a resonant frequency for each of the multiple resonant filter elements using the first model and the second model, and
adjusting an overall temperature drift of the microwave filter by using tuning mechanisms on at least one of the multiple resonant filter elements to adjust the temperature drifts of the resonant filter elements.

2. The method according to claim 1 , wherein the equivalent circuit models the multiple resonant filter elements of the microwave filter.

3. The method according to claim 1 , wherein the first temperature corresponds to room temperature.

4. The method according to claim 1 , wherein the second temperature corresponds to a temperature between 50° C. and 100° C.

5. The method according to claim 1 , wherein the microwave filter is a microwave cavity filter having multiple resonant filter cavities.

6. The method according to claim 5 , wherein the multiple resonant filter cavities are defined by a wall structure of a housing of the microwave filter and are electromagnetically coupled by openings in the wall structure.

7. The method according to claim 1 , wherein parameters of a scattering matrix are determined and stored for each temperature when measuring the frequency responses at the different temperatures.

8. The method according to claim 1 , wherein each resonant filter element is associated with one tuning mechanism.

9. The method according to claim 8 , wherein the tuning mechanism of each resonant filter element comprises one tuning element arranged on a housing of the resonant filter element, wherein the temperature drift of the associated resonant filter element is compensated for by selecting the material and/or shape of the tuning element.

10. The method according to claim 8 , wherein the tuning mechanism of one of the multiple resonant filter elements comprises at least two tuning elements arranged on a housing of the resonant one of the multiple filter elements and each extending into a cavity of the resonant one of the multiple filter elements with a shaft portion, wherein the at least two tuning elements each are movable with respect to the housing along an adjustment direction to adjust a length of the shaft portion extending into the housing.

11. The method according to claim 10 , wherein the at least two tuning elements are movable with respect to the housing independent of each other.

Assignees

• Andrew Wireless Systems Gmbh

Inventors

• Tkadlec Roman
• Hrnicko Frantisek
• Toth Gabriel

Classifications

• H01P1/30 Primary

  for compensation of, or protection against, temperature or moisture effects {; for improving power handling capability (H01P1/04, H01P1/08 take precedence)} · CPC title

• H01P1/2053

  the coaxial cavity resonators being disposed parall to each other · CPC title

• H01P1/208

  Cascaded cavities; Cascaded resonators inside a hollow waveguide structure (H01P1/205 takes precedence) · CPC title

• H01P7/06

  Cavity resonators · CPC title

• H01P1/207

  Hollow waveguide filters (H01P1/212, H01P1/213, H01P1/215, H01P1/219 take precedence) · CPC title