Variable Capacitance Circuit for Resonant Frequency Stabilization
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Solution Overview
Problem
Ferroelectric thin film capacitors used in resonant circuits for contactless communication and charging exhibit significant initial variation and temperature-dependent capacitance, making it challenging to stabilize resonant frequency and optimize transmission efficiency.
Innovation Solution
A variable capacitance circuit design incorporating multiple variable capacitance elements with direct current terminals, allowing for precise regulation of capacitance values through applied direct current voltages, ensuring opposite directional changes in capacitance values to maintain constant impedance and resonant frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If ferroelectric thin film capacitors are used to achieve miniaturization and thinning of resonant capacitors, then the device size is reduced, but the capacitance value exhibits large initial variation and strong temperature dependency
Solution Approach 1:
The patent applies parameter changes by using multiple ferroelectric thin film capacitors with different capacitance values (C1, C2, C3, C4) and applying different direct current voltages (V1, V2, V3, V4) to each capacitor. By independently controlling the capacitance parameters through voltage regulation, the system can compensate for temperature variations and initial value deviations, thereby maintaining stable resonant frequency while achieving miniaturization.
Solution Approach 2:
The patent segments the single resonant capacitor into multiple ferroelectric thin film capacitors (at least two capacitors). Each capacitor is controlled independently through separate direct current voltage terminals, allowing individual adjustment of capacitance values. This segmentation enables fine-tuned compensation for temperature and initial variation effects that would be difficult to manage in a single capacitor design.
2Reliability
If the resonant frequency is regulated by adjusting the capacitance of resonant capacitors, then communication stability is improved, but additional manufacturing steps such as trimming copper foil patterns are required, increasing production complexity
Solution Approach 1:
The patent replaces the mechanical trimming process (physically cutting or removing copper foil patterns) with an electrical control system. Direct current voltage terminals are provided to allow electronic regulation of capacitance values through applied voltages, substituting post-manufacturing mechanical adjustment with pre-manufacturing electrical control, thereby simplifying the manufacturing process while maintaining communication stability.
Solution Approach 2:
The patent introduces dynamic adjustability by providing direct current voltage terminals that enable real-time regulation of capacitance values during device operation. This allows the resonant frequency to be dynamically tuned to compensate for environmental changes and manufacturing variations without requiring complex static adjustment mechanisms or additional manufacturing steps.
3Manufacturing precision
If multiple variable capacitance elements are used to achieve thorough regulation of capacitance values, then impedance regulation precision is improved, but the device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by using the same direct current voltage terminals to simultaneously control multiple ferroelectric thin film capacitors. The voltage terminals serve both as control inputs for capacitance regulation and as part of the overall resonant circuit structure. This universal approach allows precise impedance regulation through coordinated control of multiple capacitors without proportionally increasing the number of control terminals or circuit complexity.
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 approach enables thorough regulation of capacitance values and impedance, stabilizing communication and increasing communication distance while maintaining constant resonant frequency, thus enhancing the efficiency of contactless communication and charging systems.
Implementation Method 1
a first variable capacitance element (2) including at least two variable capacitance capacitors (CS1, CS2) and having a first combined capacitance value (CS), a second variable capacitance element (4) including at least two variable capacitance capacitors (CP1, CP2) and having a second combined capacitance value (CP)
Implementation Method 2
contactless communication technologies have been established for exchanging signals through electromagnetic induction
Implementation Method 3
the power transfer technology of establishing inductive coupling or magnetic resonance between a charging device (a power transmitter) and a power-receiving device (a power receiver) through antenna coils
Data Source
AI summary
Provides is a variable capacitance circuit that is capable of efficiency optimizing antenna transmission effectively by regulating capacitance values of variable capacitance capacitors with use of direct current voltages applied to the variable capacitance capacitors. A variable capacitance circuit (1) includes a series variable capacitance element (2) and a parallel variable capacitance element (4) connected in series with the series variable capacitance element (2). The series variable capacitance element (2) includes two variable capacitance capacitors (CS1, CS2) (2a, 2b) connected in series. The parallel variable capacitance element (4) includes two variable capacitance capacitors (CP1, CP2) (4a, 4b) connected in series and a variable capacitance capacitor (CP3)(6) connected in parallel with the variable capacitance capacitors (CP1, CP2) (4a, 4b). The variable capacitance circuit (1) further includes three direct current terminals (7a, 7b, 7c).