Tuned Dielectric Waveguide Filter Frequency Adjustment
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Solution Overview
Problem
Existing dielectric waveguide filters face challenges in accurately matching the center frequency due to unknown relative permittivity of the dielectric material, making it difficult to tune individual resonators, especially in combline filters with thick film conductor patterns, which are common in use today.
Innovation Solution
The solution involves a method of tuning the center frequency by adjusting the width of the waveguide filter by removing dielectric material from its exterior side surfaces, either equally or unequally, to achieve the desired frequency, while also varying the length of slits to control RF signal bridges and electrical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual resonators are tuned to adjust center frequency, then frequency accuracy is improved, but the process becomes time consuming and labor intensive
Solution Approach 1:
The patent extracts the tuning function from individual resonators and implements it at the waveguide level by removing dielectric material from the waveguide walls. This bulk tuning approach eliminates the need for time-consuming individual resonator adjustments while achieving the desired frequency accuracy.
Solution Approach 2:
Instead of tuning individual resonators to adjust the center frequency, the patent inverts the approach by tuning the entire waveguide structure through bulk material removal. This reverse engineering approach simplifies the tuning process from multiple individual adjustments to a single bulk modification.
2Loss of time
If bulk tuning is implemented, then tuning time is reduced, but it cannot be applied to filters with thick film conductor patterns
Solution Approach 1:
The patent applies local quality by selectively removing dielectric material from specific regions of the waveguide walls where it does not interfere with the thick film conductor patterns. This localized bulk tuning maintains compatibility with modern filter designs that include conductor patterns on the waveguide surfaces.
3Manufacturing precision
If expensive tools are adjusted to match material properties, then manufacturing precision is improved, but the cost becomes impractical
Solution Approach 1:
The patent employs self-service tuning where the waveguide filter tunes itself through controlled bulk material removal after manufacturing. This eliminates the need for expensive tool adjustments to match material properties, as the tuning is performed on the actual filter component using standard precision tools.
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
This approach allows for precise tuning of the center frequency without the need for expensive tool adjustments, reducing labor and time, and effectively matches the modeled frequency response curves, improving the practicality and efficiency of waveguide filter production.
Implementation Method 1
a plurality of resonators are spaced longitudinally along the length of a monoblock
Implementation Method 2
dielectric waveguide filter
Implementation Method 3
the absence of accurate information regarding the relative permittivity of the dielectric material
Data Source
AI summary
A method of tuning the frequency of a waveguide filter including the step of removing dielectric material from one or both of the first and second opposed exterior side surfaces of the waveguide filter to cause a change in the center frequency of the waveguide filter. In one embodiment, dielectric material is removed from one or both of the first and second opposed exterior side surfaces of the waveguide filter in unequal amounts wherein the tuned waveguide filter includes first and second slits defined in the respective first and second opposed exterior side surfaces which extend unequal first and second distances into the body of the waveguide filter.