Layered High-Frequency Filter With Segmented Coupling Capacitors
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Solution Overview
Problem
Existing layered band-pass filters face difficulties in independently adjusting the capacitance of bypass capacitors and inter-stage coupling capacitors, making it challenging to control the attenuation pole and filter characteristics, especially when non-adjacent resonators are capacitively coupled.
Innovation Solution
A layered high-frequency filter design incorporating a substrate with alternately stacked dielectric and conductor layers, where specific conductor layers are used for capacitive coupling between non-adjacent resonators, with narrower portions allowing for adjustable capacitance and reduced coupling between resonators, enabling easier adjustment of filter characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If inter-stage coupling capacitor electrodes are shared between inter-stage coupling capacitors and bypass capacitors, then the number of electrodes is reduced, but it becomes difficult to control the capacitance of bypass capacitors independently of inter-stage coupling capacitors
Solution Approach 1:
The patent divides the capacitor electrodes into separate sets: inter-stage coupling capacitor electrodes for coupling adjacent resonators, and bypass capacitor electrodes for coupling non-adjacent resonators. This segmentation allows independent control of capacitance values for different capacitor functions, resolving the contradiction between reducing electrode count and maintaining independent capacitance control.
Solution Approach 2:
Different regions of the filter structure are assigned different electrode configurations tailored to their specific functions. The inter-stage coupling capacitors use one electrode configuration optimized for adjacent resonator coupling, while bypass capacitors use a different configuration for non-adjacent resonator coupling, allowing each to have independently optimized capacitance values.
2Device complexity
If non-adjacent resonators are capacitively coupled through shared electrodes, then the filter structure is simplified, but it becomes impossible to control the attenuation pole independently
Solution Approach 1:
The patent segments the coupling mechanisms by providing dedicated bypass capacitor electrodes that are distinct from inter-stage coupling capacitor electrodes. This enables separate control of the capacitive coupling between non-adjacent resonators, allowing independent adjustment of attenuation poles without affecting the overall filter structure simplicity.
3Adaptability or versatility
If adjacent resonators are capacitively coupled, then the pass-band width can be adjusted, but the magnetic field coupling between non-adjacent resonators cannot be eliminated
Solution Approach 1:
The patent extracts and eliminates the harmful magnetic field coupling effect by carefully designing the physical layout and orientation of resonators and capacitors. The bypass capacitors are positioned and configured to provide capacitive coupling between non-adjacent resonators without creating significant magnetic field interaction, thereby taking out the harmful magnetic coupling while preserving useful capacitive coupling.
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 design allows for precise adjustment of the filter's characteristics by controlling the capacitance between non-adjacent resonators, enhancing the pass-band width and attenuation outside the pass band, while reducing the size of the filter.
Implementation Method 1
a first conductor layer for capacitive coupling... a first portion for forming a first capacitor between itself and the first resonator; a second portion for forming a second capacitor between itself and the second resonator
Implementation Method 2
The first and third resonators are inductively coupled to each other while the second and third resonators are inductively coupled to each other
Data Source
AI summary
A high frequency filter incorporates first to third resonators provided inside a layered substrate. The first and third resonators are adjacent to each other and inductively coupled to each other. The second and third resonators are also adjacent to each other and inductively coupled to each other. The first and second resonators are not adjacent to each other but are capacitively coupled to each other through a conductor layer for capacitive coupling. The conductor layer for capacitive coupling incorporates: a first portion for forming a first capacitor between itself and the first resonator; a second portion for forming a second capacitor between itself and the second resonator; and a third portion having an end connected to the first portion and the other end connected to the second portion, the ends being opposed to each other in the longitudinal direction. The width of at least part of the third portion is smaller than the width of each of the first portion and the second portion.