Switchable Filter Circuit for Multi-Band Frequency Selection
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Solution Overview
Problem
The existing bandpass filters struggle to selectively switch between different frequency bands and center frequencies, allowing unnecessary signals outside the desired band to pass and failing to adjust the center frequency of single-band filters.
Innovation Solution
A filter circuit design featuring multiple transmission lines with specific electrical lengths and switches, allowing for selective switching between different frequency bands by adjusting the connection of open end parts and inductors, enabling the circuit to function as a filter for multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bandpass filter is configured to support multiple frequency bands simultaneously, then the filter can pass signals of multiple frequency bands at the same time, but it also passes unnecessary waves outside the desired band and cannot selectively switch the center frequency
Solution Approach 1:
The patent applies dynamics by making the filter circuit configurable through switchable connections. The resonator can be connected to different transmission lines (first, second, or third) by changing the connection state, allowing the filter to dynamically adapt its frequency response. This dynamic reconfiguration enables selective passing of desired frequency bands while blocking unnecessary waves, resolving the contradiction between multi-band support and harmful wave passing.
Solution Approach 2:
The patent applies local quality by creating different filter configurations for different frequency bands. Each transmission line (first, second, third) is designed with specific electrical lengths (one-quarter wavelength, one-half wavelength, etc.) to optimize performance for particular frequency ranges. By selectively connecting the resonator to different transmission lines, the filter achieves optimal local performance for the desired band while suppressing unwanted bands.
2Measurement precision
If a bandpass filter is designed as a single-band filter, then it can selectively pass a specific frequency band, but it is unable to switch the center frequency into different frequencies
Solution Approach 1:
The patent applies universality by designing a single filter circuit that can perform multiple functions: it can operate as a single-band filter with selectable center frequencies or as a dual-band filter. The resonator can be connected to different transmission lines depending on the desired operating mode, making the filter universally applicable across multiple frequency bands and operational configurations without requiring separate filter circuits for each function.
Solution Approach 2:
The patent applies dynamics by enabling the filter to switch between different operational states. By changing the connection state of the resonator to different transmission lines, the center frequency of the single-band filter can be dynamically adjusted. This dynamic reconfiguration allows the same physical filter circuit to maintain high frequency selectivity while adapting to different center frequency requirements.
3Adaptability or versatility
If transmission lines with different electrical lengths are used to support multiple frequency bands, then the filter can cover broader frequency ranges, but the circuit complexity increases
Solution Approach 1:
The patent applies merging by combining multiple transmission lines (first, second, third) with different electrical lengths into a single integrated filter circuit. Instead of using separate filter circuits for different frequency bands, the invention merges them into one circuit where the resonator can be selectively connected to different transmission lines. This merging approach achieves broad frequency band coverage while avoiding the complexity of multiple independent filter circuits.
Solution Approach 2:
The patent applies segmentation by dividing the filter circuit into distinct functional segments: the resonator, multiple transmission lines with different electrical lengths, and switching mechanisms. Each transmission line is designed with specific electrical length characteristics (one-quarter wavelength, one-half wavelength, etc.) to handle specific frequency ranges. This segmentation allows the circuit to cover broad frequency ranges while maintaining manageable complexity through modular design.
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 filter circuit can selectively switch the center frequency among multiple frequency bands, effectively suppressing unwanted signals and allowing only desired frequencies to pass, enhancing frequency selectivity and filtering performance.
Implementation Method 1
a first transmission line that has an electrical length being a one-quarter length of a first wavelength... Each of a transmission line composed of the first open end part, the second transmission line, and the fifth transmission line, and a transmission line composed of the second open end part, the third transmission line, and the sixth transmission line, has an electrical length being a one-quarter length of a second wavelength
Data Source
AI summary
A first switch is configured to open and close connection between an end part of a first transmission line and ground, and a second switch is configured to open and close connection between an end part of a third transmission line and ground.