Variable Inductor With Movable Electroconductive Member
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Solution Overview
Problem
Conventional variable inductors can only vary inductance within a relatively small range, limiting their ability to meet the increasing demands for smaller, high-frequency RF circuits in radio communications equipment.
Innovation Solution
A variable inductor design featuring a conductor coil and an electroconductive member that can move closer to or farther from the coil, generating a magnetic field and induced current to adjust inductance over a wide range, with a flat spiral coil and electroconductive film arrangement to enhance electromagnetic interference and inductance change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a ferrite core is moved closer to or farther from the coil to vary inductance, then the inductance can be adjusted, but the inductance can only be varied within a relatively small range of approximately 10%
Solution Approach 1:
The patent changes the fundamental parameter used for inductance adjustment from magnetic permeability (ferrite core) to electrical conductivity (electroconductive member). By moving a highly conductive member closer to or farther from the coil, the induced current and resulting magnetic field interference change, causing significant inductance variation. This parameter substitution enables wide-range inductance adjustment without increasing structural complexity
Solution Approach 2:
The patent converts the harmful electromagnetic interference effect into a beneficial mechanism for inductance adjustment. The electroconductive member's induced current creates a magnetic field that opposes and weakens the coil's magnetic field, and this previously considered interference is now utilized as the primary mechanism for achieving wide-range inductance variation
2Productivity
If the electroconductive member is placed close to the coil, then the inductance decreases, but the rate of inductance change must be maximized
Solution Approach 1:
The patent utilizes the non-linear relationship between distance and inductance change rate by positioning the electroconductive member at optimal distances. The design accepts that precise distance control is needed but compensates by operating in the region where small distance changes produce large inductance variations, maximizing the effective control range
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 achieves a large rate of inductance change, allowing for greater variability and suitability for wide-range inductance adjustment, surpassing the limitations of conventional inductors.
Implementation Method 1
the current causes a magnetic field (a first magnetic field) to be generated around the coil. The first magnetic field causes an induced current to flow in the electroconductive member, and the induced current causes a magnetic field (a second magnetic field) to be generated around the electroconductive member.
Data Source
AI summary
A variable inductor includes a conductor and an electroconductive member. The conductor has a coil and a pair of terminals electrically connected with the coil. The electroconductive member is movable closer to and farther away from the coil. The inductance between the terminals becomes smaller as the distance between the coil and the electroconductive member becomes shorter. Conversely, the inductance between the terminals becomes larger as the distance between the coil and the electroconductive member becomes longer.