Extractor Inductor Bypass Path for Harmonic Isolation
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Solution Overview
Problem
In extractors combining band pass filters and band elimination filters, isolation is reduced in frequency bands higher than the stop band due to harmonic waves, leading to degraded insertion loss.
Innovation Solution
The inclusion of a first inductor connected in series or parallel on the path between the common terminal and the external connection terminal, inductively coupled to the second inductor in the band elimination filter, creates a bypass path for radio-frequency signals, reducing insertion loss by preferentially transmitting signals in the frequency band higher than the stop band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a band pass filter and band elimination filter are combined in an extractor, then multi-frequency band support is achieved, but isolation between filters is reduced in frequency bands higher than the stop band due to harmonic waves
Solution Approach 1:
A first inductor is introduced as an intermediary component connected in series or parallel on the path between the common terminal and the external connection terminal. This first inductor is inductively coupled to the second inductor in the band elimination filter, creating a bypass path that mediates between the harmonic waves and the filter isolation, allowing high-frequency signals to bypass the problematic filter interaction region while maintaining the multi-frequency band support capability
2Adaptability or versatility
If a band pass filter and band elimination filter are combined in an extractor, then multi-frequency band support is achieved, but insertion loss is degraded in frequency bands higher than the stop band
Solution Approach 1:
The signal path is segmented into multiple paths: the main path through the filters and a bypass path through the first and second inductors. This segmentation allows different frequency components to take different paths - lower frequency signals pass through the filters while higher frequency signals (harmonic waves) utilize the bypass path, thereby reducing insertion loss in frequency bands higher than the stop band while maintaining multi-frequency band support
3Reliability
If isolation between filters is improved, then frequency selectivity is enhanced, but device complexity increases
Solution Approach 1:
The first inductor serves multiple functions simultaneously: it provides the bypass path for high-frequency signals, couples inductively to the second inductor to enable frequency-selective isolation, and maintains compatibility with the existing band pass and band elimination filter structures. This multi-functionality achieves improved isolation without proportionally increasing device 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 configuration effectively compensates for the degradation in insertion loss in the frequency band higher than the stop band, optimizing bandpass characteristics and reducing the size of the extractor while maintaining high-quality signal transmission.
Implementation Method 1
The first inductor is inductively coupled to the second inductor
Data Source
AI summary
An extractor includes an external connection terminal, a common terminal, input-output terminals, a band elimination filter that is connected to the common terminal and the first input-output terminal input-output terminal and that uses a first frequency band as a stop band, a band pass filter connected to the common terminal and the second input-output terminal and that uses a second frequency band overlapped with at least a portion of the first frequency band as a pass band, and an inductor connected on a path connecting the common terminal to the external connection terminal. The band elimination filter includes series arm resonators located on a series arm connecting the common terminal to the input-output terminal and an inductor that is located on the series arm between the series arm resonator and the first input-output terminal. The inductor is inductively coupled to the inductor.