Overlapping Electrode LC Filter Circuit for Compact Capacitance
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Solution Overview
Problem
Existing filter circuits, such as those described in Japanese Unexamined Patent Application Publication No. 2006-262349, require larger electrodes to ensure adequate capacitance, leading to increased size and potentially inefficient resonance characteristics.
Innovation Solution
A filter circuit design that incorporates an LC circuit with a substrate and electrodes configured to overlap partially, forming capacitors with reduced electrode area while maintaining sufficient electrostatic capacitance, thereby allowing for a smaller filter circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of electrodes is increased to ensure the capacitance of capacitors, then the capacitance is sufficient, but the filter circuit size increases
Solution Approach 1:
The patent transitions from planar electrode arrangement to three-dimensional overlapping arrangement. The first and second electrodes are positioned at different heights (different z-dimension) with partial overlap in the planar view, creating capacitance through vertical stacking rather than horizontal expansion. This dimensional change allows sufficient capacitance in a compact footprint.
Solution Approach 2:
The electrode structure implements a nested configuration where the first electrode and second electrode are positioned at different vertical levels with partial horizontal overlap. This nesting in the vertical dimension allows the capacitor to achieve adequate capacitance without requiring large planar area, effectively packing the electrical function into a smaller spatial envelope.
2Area of stationary object
If the electrode area is reduced to make the filter circuit smaller, then the filter circuit size decreases, but the capacitance becomes insufficient
Solution Approach 1:
The invention compensates for reduced planar electrode area by utilizing the vertical dimension. The overlapping configuration in the thickness direction creates effective capacitance through the vertical stacking of electrodes, allowing the filter circuit to maintain sufficient capacitance while reducing its planar footprint.
Solution Approach 2:
The patent changes the geometric parameters of the capacitor by transitioning from large planar area to compact overlapping structure. By adjusting the overlap area and separation distance in the vertical dimension, the design achieves adequate capacitance with significantly reduced electrode area, resolving the contradiction between size and 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 proposed filter circuit achieves desired filter characteristics with reduced size, as the overlapping electrode configuration allows for effective capacitance without the need for larger electrodes, thus enabling a more compact design.
Implementation Method 1
A portion of the first electrode overlapping with the second electrode is the one electrode of the first capacitor. A portion of the second electrode overlapping with the first electrode is the other electrode of the first capacitor. A portion of the second electrode overlapping with the third electrode is the one electrode of the second capacitor. A portion of the third electrode overlapping with the second electrode is the other electrode of the second capacitor.
Data Source
AI summary
A filter circuit includes an LC circuit having one end connected to a signal path connecting an input terminal and an output terminal and the other end connected to a reference potential. A filter circuit according to a first embodiment includes a substrate and a plurality of electrodes provided on a main surface of the substrate or inside the substrate. The LC circuit includes a first capacitor, a first inductor connected in parallel, and a second capacitor connected in series. The electrodes overlap with each other at least partially when viewed in a thickness direction of the substrate. Portions of the electrodes overlapping with each other are electrodes of the first capacitor or the second capacitor.