Controllable Frequency Selective Surface with Variable Capacitance
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Solution Overview
Problem
Frequency-selective surface devices are limited in that their functional bandwidth is fixed and cannot switch between band-pass and band-stop modes of operation.
Innovation Solution
Incorporating variable capacitance coupling components that connect elementary conductive patterns on a substrate, allowing for electrical or thermal control of capacitance to selectively vary the device's mode of operation between band-pass and band-stop modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a periodic pattern of conductive elements is used to create a frequency-selective surface, then the device can filter electromagnetic waves at specific frequencies, but the functional bandwidth and mode of operation (band-pass or band-stop) are fixed and cannot be modified
Solution Approach 1:
The patent applies the dynamics principle by making the coupling between elementary patterns controllable and variable. Variable capacitors are integrated into the coupling structures, allowing the electrical connection between adjacent patterns to be dynamically adjusted. This enables the device to switch between different operational modes (band-pass and band-stop) and adjust its functional bandwidth by changing the capacitance values, thereby transforming a static structure into a dynamically adaptable one.
Solution Approach 2:
The patent implements parameter changes by modifying the electrical parameters of the coupling components. By varying the capacitance values of the integrated capacitors, the resonant frequencies and operational characteristics of the frequency-selective surface are changed. This allows the device to operate in different modes and adjust its bandwidth without changing the physical geometry of the conductive patterns themselves.
2Adaptability or versatility
If variable capacitors are integrated to make the FSS active and variable, then the rejected frequency becomes variable, but the device cannot operate selectively in bandpass mode or in bandstop mode
Solution Approach 1:
The patent applies local quality by differentiating the coupling characteristics in different spatial directions. Different sets of variable capacitors are arranged along different axes (e.g., x-direction and y-direction), and by selectively controlling the capacitance values in different directions, the device can achieve different operational modes. This directional differentiation enables mode selection capability while maintaining frequency variability.
3Adaptability or versatility
If different modes of metallization are used to vary the mode of operation, then the device can operate in band-stop or band-pass mode, but it is not possible to operate the same device selectively in both modes
Solution Approach 1:
The patent implements universality by designing a single device structure that can perform multiple functions - both band-pass and band-stop filtering. By integrating variable capacitors into a unified periodic pattern structure, the device achieves multi-functionality through electrical control rather than requiring separate devices or complex multi-layer metallization structures for different modes.
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
Enables the device to operate selectively in both band-pass and band-stop modes, with adjustable operating frequency and bandwidth, enhancing its multifunctionality and adaptability.
Implementation Method 1
a first set of variable capacitors, each capacitor of the first set of variable capacitors connecting two elementary conductive patterns (8) to each other
Implementation Method 2
When this arrangement of elements is subjected to an incident plane electromagnetic wave, the latter is partly transmitted and partly reflected. Under certain resonance conditions, the amplitude of the transmitted wave is equal to 0, the energy being reflected or diffused
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
This device comprises a substrate, a network of elementary conductive patterns (8) printed on a surface of said substrate, and a network of coupling components (12, 12a, 12b), each connecting two adjacent elementary conductive patterns (8) and having a modifiable capacitance. The device comprises a control assembly for selectively controlling the value of the capacitances of groups (20a, 20b) of coupling components (12, 12a, 12b) according to a first band-stop mode, in which the capacitance of the assembly of groups (20a, 20b) is fixed at a given value, and a second band-pass mode, in which the capacitance of the coupling components (12, 12a, 12b) of a first assembly of groups (20a) is fixed at a first value, and the capacitance of the coupling components (12, 12a, 12b) of a second assembly (20b) of groups, complementary to the first assembly, is fixed at a second value.