Parallel LC Resonator Filter for Low-Frequency Signal Loss
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Solution Overview
Problem
Existing filter devices experience signal loss due to impedance deviation at frequencies lower than the attenuation band of parallel resonance, particularly in radio frequency circuits.
Innovation Solution
Incorporating a first and second series resonator connected in parallel, with the second resonator having a lower resonant frequency than the first, to reduce signal loss in frequency bands below the attenuation band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second inductor is connected in parallel to a first series circuit (first inductor and first capacitor) to form a filter device, then reactance characteristics increase at frequencies lower than the attenuation band of parallel resonance, but signal loss occurs due to impedance deviation
Solution Approach 1:
The filter device is segmented into multiple series resonators (first series resonator with inductor L1 and capacitor C1, second series resonator with inductor L2 and capacitor C2) connected in parallel. Each resonator operates at a different resonant frequency, with the second resonator's resonant frequency being lower than the first. This segmentation allows the filter to maintain good reactance characteristics at frequencies lower than the parallel resonance attenuation band while reducing signal loss through coordinated operation of multiple resonators.
2Device complexity
If only a second inductor is used, then the device complexity is low, but reactance characteristics deteriorate at frequencies lower than the attenuation band of parallel resonance
Solution Approach 1:
Multiple series resonators are merged in parallel configuration within the filter device. The first series resonator (L1, C1) and second series resonator (L2, C2) work together, with their resonant frequencies strategically positioned (second resonant frequency lower than first). This merging provides complementary reactance characteristics across different frequency ranges, improving overall reliability without excessive complexity increase.
3Loss of energy
If multiple series resonators with different resonant frequencies are connected in parallel, then signal loss is reduced at frequencies lower than the attenuation band, but device complexity increases
Solution Approach 1:
The filter device utilizes parameter changes by setting specific resonant frequencies for each series resonator. The second series resonator is designed with a lower resonant frequency than the first series resonator, and the parallel resonance attenuation band is positioned between these resonant frequencies. This parameter optimization reduces signal loss at frequencies lower than the attenuation band while maintaining manageable device complexity through systematic frequency allocation.
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 configuration allows for reduced signal loss and steep attenuation characteristics near the parallel resonant frequency, enhancing signal transmission and reception in passbands.
Implementation Method 1
a first series resonator to resonate in series at a first resonant frequency with a first inductor L1 and a first capacitor C1 connected in series to the first inductor L1 and a second series resonator to resonate in series at a second resonant frequency
Implementation Method 2
The first series resonator and the second series resonator are connected in parallel to each other and resonate in parallel at a third resonant frequency
Data Source
AI summary
A filter device includes a first LC series resonator to resonate in series at a first series resonant frequency with a first inductor and a first capacitor, and a second LC series resonator to resonate in series at a second series resonant frequency with a second inductor and a second capacitor. The first and second LC series resonators are connected in parallel and resonate in parallel at a parallel resonant frequency. The second series resonant frequency is lower than the first series resonant frequency. The parallel resonant frequency is between the first and second series resonant frequencies.