Strip Line Interdigital Filter Via Position Compensation
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Solution Overview
Problem
Microwave circuits in strip line technology face deviations in via positions relative to resonator strips, leading to variations in effective electrical length and resonance frequency, resulting in degraded frequency response and bandwidth drops in interdigital filters.
Innovation Solution
Designing the ends of resonator strips to maintain identical effective electrical length with vias by positioning them in the same direction or using elongated or extension resonator strips, ensuring consistent resonance frequency across deviations, thus minimizing frequency response degradations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vias are drilled and metalized independently from resonator strip processing, then manufacturing process flexibility is improved, but via position deviation relative to resonator strips occurs
Solution Approach 1:
The via positions are pre-calculated taking into account the effective electrical length influence, and this preliminary design data is used to compensate for the independent processing deviations. The via positions are determined in advance with correction values that account for their impact on resonator electrical length, so that even when drilled independently, they achieve the desired electrical characteristics.
Solution Approach 2:
The via positions are adjusted as a parameter to compensate for their independent processing. By calculating the effective electrical length influence of each via and adjusting the via positions accordingly, the design parameters are changed to account for the independent manufacturing process, ensuring that the final electrical performance meets specifications despite processing separation.
2Manufacturing precision
If via positions deviate from optimal positions, then manufacturing tolerance is improved, but resonance frequency variation increases
Solution Approach 1:
The via positions are adjusted as a parameter to compensate for their independent processing. By calculating the effective electrical length influence of each via and adjusting the via positions accordingly, the design parameters are changed to account for the independent manufacturing process, ensuring that the final electrical performance meets specifications despite processing separation.
Solution Approach 2:
The design process incorporates feedback by calculating the effective electrical length influence of each via on its corresponding resonator strip and using this information to adjust via positions. This feedback loop ensures that even with manufacturing deviations, the final resonance frequencies remain consistent with design specifications.
3Ease of manufacture
If effective electrical length of resonator strips varies, then via positioning flexibility is improved, but filter frequency response degrades
Solution Approach 1:
The via positions are adjusted as a parameter to compensate for their independent processing. By calculating the effective electrical length influence of each via and adjusting the via positions accordingly, the design parameters are changed to account for the independent manufacturing process, ensuring that the final electrical performance meets specifications despite processing separation.
Solution Approach 2:
The design proactively compensates for the effective electrical length variations by pre-calculating via positions that account for their influence on resonator strips. This preliminary anti-action prevents frequency response degradation before it occurs, rather than attempting to correct it after manufacturing deviations happen.
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
The approach results in a consistent band pass filter spectrum without distinct drops, maintaining a constant central frequency and minimizing insertion loss and return loss, even with deviations in via positions, thereby enhancing the microwave circuit's performance.
Implementation Method 1
Microwave circuits in strip line technology filtering or coupling microwave signals contain metallic resonator strips on a dielectric layer substrate
Implementation Method 2
The resonance frequency of a resonator strip depends on the geometry of a resonator strip and is additionally influenced by the geometry of the via and by the position of the via in relation to the resonator strip
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5A
AI summary
A microwave circuit (1) in strip line technology contains metallic resonator strips (21, 22, 23, 24, 25, 26, 27, 28, 29) on one side of a dielectric layer. Alternately another end of consecutive resonator strips (21, 22, 23, 24, 25, 26, 27, 28, 29) is connected by means of at least one via (61, 62, 63, 64, 65, 66, 67, 68, 69; 61', 62', 63', 64', 65', 66', 67', 68', 69'; 6) to a metallic surface on an opposite side of said dielectric layer. Said end of each resonator strip (21, 22, 23, 24, 25, 26, 27, 28, 29) is connected to at least one via (61, 62, 63, 64, 65, 66, 67, 68, 69, 61', 62', 63', 64', 65', 66', 67', 68', 69) and is formed relative to said at least one via (61, 62, 63, 64, 65, 66, 67, 68, 69, 61', 62', 63', 64', 65', 66', 67', 68', 69' ; 6, 6'; 6", 6"'; 6"") so that the effective electrical length of each resonator strip (21, 22, 23, 24, 25, 26, 27, 28, 29) connected through the via (61, 62, 63, 64, 65, 66, 67, 68, 69, 61' ,62', 63', 64',65', 66', 67', 68', 69') is identical.