Tuning Fixture for Ceramic Filters with Segmented Plates
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Solution Overview
Problem
Ceramic filters in radio equipment require simultaneous tuning and measurement, but existing methods are hindered by the need for a ground plane, which blocks access to the top patterned surface, preventing simultaneous probing of resonators during measurement.
Innovation Solution
A fixture with a bottom plate and top plate separated by a predetermined height, featuring a window to expose the filter's through-hole and RF ports for signal and ground connections, allowing for simultaneous measurement and tuning by positioning the filter between the plates and using a slider mechanism for precise adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a ground plane is attached to the bottom surface of the filter to reduce interference, then electromagnetic interference is reduced, but access to the top patterned surface is blocked preventing simultaneous measurement and tuning
Solution Approach 1:
The fixture is divided into two separate plates: a bottom plate that provides the ground plane connection and a top plate that provides access to the top patterned surface. This segmentation allows both the ground plane functionality and the tuning access to coexist without interference, resolving the contradiction between electromagnetic shielding and operational accessibility.
2Reliability
If the filter is mounted on a ground plane for proper operation, then filter performance is improved, but simultaneous measurement and probing of resonators is prevented
Solution Approach 1:
The fixture acts as an intermediary device that mediates between the ground plane requirement and the measurement/tuning requirement. By providing a structured platform with separated top and bottom plates, the fixture enables both functions to occur simultaneously - the ground plane is provided through the bottom plate while the top plate allows access for probing and measurement, thus resolving the contradiction between reliability and productivity.
3Reliability
If traditional measurement fixtures are used with ground plane attachment, then proper filter operation is ensured, but measurement and tuning must be performed separately increasing time and cost
Solution Approach 1:
The fixture merges the measurement and tuning functions into a single integrated platform. By combining the ground plane provision (bottom plate) with the top surface access (top plate) in one fixture structure, both measurement and tuning can be performed simultaneously on the same filter, eliminating the need for separate operations and reducing time loss while maintaining proper filter operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables fast, automated, and highly repeatable measurement and tuning of RF ceramic filters, reducing costs and achieving performance comparable to filters mounted on printed circuit boards, with over 99% correlation in transmission characteristics.
Implementation Method 1
This technique allows capacitive coupling between resonators
Data Source
AI summary
The application at least describes a tuning and measurement fixture. The fixture comprises a bottom plate including side surfaces, a top surface and a bottom surface. The bottom plate includes a window extending between the top and bottom surfaces. The window can expose a through-hole of a filter positioned in the fixture. In addition, the top surface of the filter includes a signal connection and a ground connection configured to communicate with the filter. The bottom surface of the filter includes an RF port configured to transmit electrical characteristics of the filter. A top plate of the filter includes a top and a bottom surface. The top plate is separated from the bottom plate by a predetermined height. The top plate includes a window extending between the top and bottom surfaces. The window exposes the through-hole of the filter held in the fixture. The application also describes a method of tuning and measuring a filter in a fixture.