Noise Filter Array Inductance Variation Reduction
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Solution Overview
Problem
Existing noise filter arrays with integrated LC series resonant circuits suffer from variations in inductance values among filter elements due to unequal distances from capacitors to the ground terminal, leading to inconsistent filter characteristics.
Innovation Solution
A noise filter array design where LC series resonant circuits are formed with a common inductance adjusting conductor, ensuring equal lengths from the connection point to the ground terminal, and optionally featuring a meander or linear shape, symmetric configuration, and additional via holes to reduce inductance variations and magnetic influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If coils in LC series resonant circuits are integrated to simplify structure, then device complexity is reduced, but inductance values vary among filter elements due to unequal distances to ground terminal
Solution Approach 1:
The patent applies equipotentiality by ensuring that all ground-side electrodes of capacitors in different filter elements are connected to the ground terminal through conductors of equal length. This equalizes the inductance values among all LC series resonant circuits, eliminating the variation problem that arose from unequal distances to ground. The solution maintains structural simplification through integration while achieving inductance consistency.
2Ease of manufacture
If a common inductance adjusting conductor is used for all filter elements, then manufacturing cost is reduced, but variations in inductance values arise due to different connection distances
Solution Approach 1:
The patent resolves this contradiction by designing the common inductance adjusting conductor such that the distance from each capacitor's ground-side electrode to the ground terminal is equal. This equipotential design ensures uniform inductance values across all filter elements while maintaining the cost benefits of using a single common conductor for all connections.
3Device complexity
If filter elements are arranged in an array with integrated grounding, then structure is simplified, but characteristic variations occur among filter elements
Solution Approach 1:
The patent applies equipotentiality to the array structure by ensuring that all ground-side electrodes in the array are connected to the ground terminal through conductors of equal length. This equalizes the inductance values and stabilizes the resonance frequencies of all filter elements in the array, eliminating characteristic variations while maintaining the simplified integrated structure.
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 reduces inductance variations among filter elements, stabilizes resonance frequencies, and simplifies the structure, enhancing the uniformity of filter characteristics and reducing manufacturing stress, while allowing for cost-effective production and efficient noise removal across multiple communication bands.
Implementation Method 1
a plurality of filter elements formed of an LC parallel resonant circuit and an LC series resonant circuit, each of which has a coil and a capacitor
Implementation Method 2
an LC parallel resonant circuit and an LC series resonant circuit, each of which has a coil and a capacitor
Data Source
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AI summary
A noise filter array that maintains a simple structure overall and that eliminates variations in characteristic among a plurality of filter elements is provided. Filter elements F1 to F4, each of which is formed of an LC parallel resonant circuit having a coil and a capacitor and an LC series resonant circuit having a coil and a capacitor, are arranged parallel to one another in an array and integrally formed. Grounding capacitors C12 to C42 that respectively constitute the filter elements F1 to F4 are arranged so that the common ground-side electrode 9 faces the signal-side electrodes 8 and is connected to an inductance adjusting conductor L0 that constitutes the LC series resonant circuits with the capacitors through a via hole 7. The lengths of the inductance adjusting conductor L0 from a connection position with the via hole 7 to ground terminals GND1 and GND2 are equal among the filter elements F1 to F4.