High-frequency Filter Floating Conductor Shielding
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Solution Overview
Problem
Existing high-frequency filters with laminated band pass designs face challenges in achieving desired pass band characteristics due to unintended capacitive coupling between non-adjacent LC parallel resonators, particularly between the between-input-and-output capacitor electrode and the ground electrode.
Innovation Solution
A high-frequency filter design featuring a laminated body with three or more LC parallel resonators aligned in a predetermined direction, where adjacent resonators are electromagnetic-field-coupled, and a floating conductor is used to reduce unintended capacitive coupling by increasing the distance between the floating conductor and the ground conductor, thereby enhancing the desired pass band characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the between-input-and-output capacitor electrode is located near the capacitor electrodes to produce coupling capacitance between non-adjacent LC parallel resonators, then the desired pass band characteristic is obtained, but unintended capacitive coupling occurs between the between-input-and-output capacitor electrode and the ground electrode
Solution Approach 1:
The patent introduces a new spatial dimension by placing the floating conductor on an intermediate layer between the ground electrode and the between-input-and-output capacitor electrode. This dimensional arrangement allows the floating conductor to act as a shield, reducing the unintended capacitive coupling in the vertical direction while maintaining the necessary coupling capacitance between non-adjacent LC parallel resonators in the horizontal direction.
Solution Approach 2:
The floating conductor serves as an intermediary element that mediates between the ground electrode and the between-input-and-output capacitor electrode. By positioning this intermediate conductor strategically, the patent reduces the direct capacitive coupling between the ground electrode and the capacitor electrode, thereby eliminating the harmful unintended coupling while preserving the desired pass band characteristic.
2Reliability
If LC parallel resonators are capacitively coupled to each other to obtain desired pass band characteristic, then the filter performance is improved, but unintended capacitive coupling with ground electrode occurs
Solution Approach 1:
The patent utilizes the vertical layering dimension to introduce the floating conductor as a shielding element. This dimensional approach allows the desired capacitive coupling between non-adjacent LC parallel resonators to occur in the horizontal plane while the floating conductor blocks the unintended vertical coupling path to the ground electrode.
Solution Approach 2:
The floating conductor acts as an intermediary shield that selectively blocks capacitive coupling paths. It mediates the electromagnetic field distribution to allow necessary coupling between resonators while preventing harmful coupling with the ground electrode, thus improving overall filter performance.
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 design effectively achieves a desired pass band characteristic by minimizing unintended capacitive coupling between non-adjacent LC parallel resonators, allowing for efficient capacitive coupling between the resonators while preventing coupling with the ground, thus optimizing frequency response.
Implementation Method 1
Capacitor electrodes 411, 412, 413, and 414 in the capacitor electrode forming layer 402 face a ground electrode 409. As a result, capacitors C501 to C504 illustrated in FIG. 11 are configured.
Implementation Method 2
A via electrode 431 connects the capacitor electrode 411 and one end of a line electrode 616 to each other, and a via electrode 432 connects the other end of the line electrode 616 and the ground electrode 409 to each other. Accordingly, an inductor L501 illustrated in FIG. 11 is configured.
Implementation Method 3
the laminated band pass filter 500 includes a four-stage LC parallel resonance circuit and a coupling capacitance C514
Implementation Method 4
since unintended capacitive coupling occurs between the between-input-and-output capacitor electrode 260 and the ground electrode 409
Data Source
AI summary
In a high-frequency filter, four LC parallel resonators include four capacitors and four resonance coils, and are aligned in a predetermined direction. The four capacitors are defined by a ground conductor and a resonance capacitor conductor. The four coils are defined by a first via conductor, a second via conductor, and a line conductor. A floating conductor is provided astride within the four coils, and a sum of electrostatic capacitance between line conductors and the floating conductor is larger than electrostatic capacitance between the resonance capacitor conductor and the floating conductor, the line conductors overlapping with the floating conductor in planar view from a lamination direction.