Multilayer Composite Filter Layout for Low Insertion Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing composite filter devices face increased insertion loss in the pass band due to stray capacitance generated by longer wiring electrodes required to provide a predetermined inductance, which deteriorates the filter's performance.
Innovation Solution
A composite filter device design featuring overlapping wiring electrodes on a multilayer board, where first and second inductors are connected in series between filters, allowing for reduced wiring electrode length and electromagnetic coupling, thereby minimizing stray capacitance and maintaining predetermined inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the length of wiring electrode is increased to provide predetermined inductance, then the inductance value is achieved, but the insertion loss in pass band is deteriorated due to stray capacitance
Solution Approach 1:
The patent transitions from planar wiring electrode layout to a three-dimensional stacked configuration where first and second wiring electrodes are positioned on different layers of the substrate. This vertical stacking enables electromagnetic coupling between layers, achieving the required inductance with shorter electrode lengths and reduced stray capacitance.
Solution Approach 2:
The patent combines multiple wiring electrodes (first and second wiring electrodes) into a coupled inductor structure where the electrodes are positioned to overlap or adjacent to each other. This merging creates mutual inductance that enhances the total inductance value while keeping individual electrode lengths short, thereby reducing stray capacitance.
2Quantity of substance
If the length of wiring electrode is increased to provide predetermined inductance, then the inductance value is achieved, but the stray capacitance is generated
Solution Approach 1:
The patent positions wiring electrodes on different layers (vertical dimension) rather than extending them in the same plane. This spatial separation in the vertical direction enables inductive coupling while minimizing planar overlap that causes stray capacitance, thus achieving high inductance with low parasitic capacitance.
Solution Approach 2:
The patent uses multiple copies of wiring electrodes (first and second wiring electrodes) positioned in different locations and layers. These copied electrodes are coupled together to achieve the required total inductance, distributing the inductive function across multiple shorter elements rather than relying on a single long electrode that would generate excessive stray capacitance.
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 solution effectively reduces insertion loss in the pass band while providing a predetermined inductance, enhancing the filter's performance, especially in high-frequency bands by reducing stray capacitance and increasing self-resonant frequencies.
Implementation Method 1
The first wiring electrode and the second wiring electrode at least partially overlap when the multilayer board is viewed in plan
Data Source
AI summary
A composite filter device includes a connection portion connected to a common terminal, a first filter between the connection portion and a first terminal, a second filter between the connection portion and a second terminal, a first inductor that is connected in series between the second filter and the connection portion, includes a first wiring electrode wound in a predetermined direction, and is provided at an internal layer of a multilayer board, and a second inductor that is connected in series between the common terminal and the connection portion, includes a second wiring electrode wound in the predetermined direction, and is provided at an internal layer of the multilayer board. The first and second wiring electrodes at least partially overlap when the multilayer board is viewed in plan.