Layered Low-Pass Filter With Multiple Stop-Band Attenuation Poles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing low-pass filters struggle to increase attenuation in multiple specific narrow frequency bands within the stop band without increasing insertion loss in the pass band, especially when multiple notch filters are used in series, and adjusting the attenuation pole closest to the pass band is insufficient for achieving steep attenuation across various frequency bands.
Innovation Solution
A layered low-pass filter design featuring a series connection of first and second inductors between input and output terminals, with additional capacitors and inductors configured to create multiple attenuation poles within the stop band, allowing for increased attenuation in specific narrow frequency bands by adjusting the inductances of the third to fifth inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple notch filters are provided in series to increase attenuation in specific narrow frequency bands, then attenuation in those frequency bands is improved, but insertion loss in the pass band increases
Solution Approach 1:
The invention divides the single attenuation function into multiple separate attenuation poles distributed across different frequency bands. Each attenuation pole (first through fifth) targets specific narrow frequency bands independently, allowing selective attenuation without requiring multiple cascaded notch filters that would accumulate insertion loss.
Solution Approach 2:
The invention changes the inductance values of the third through fifth inductors to adjust the frequencies at which the attenuation poles occur. By varying these inductance parameters, the filter can target different specific frequency bands while maintaining low insertion loss in the pass band, avoiding the need for multiple fixed notch filters.
2Reliability
If the attenuation pole closest to the pass band is adjusted to increase attenuation, then attenuation near the pass band is improved, but attenuation in higher frequency bands remains insufficient
Solution Approach 1:
The invention segments the attenuation function across multiple frequency regions by creating five distinct attenuation poles. The first attenuation pole handles frequencies near the pass band, while the second through fifth attenuation poles independently handle higher frequency bands, ensuring comprehensive attenuation coverage across the entire stop band.
Solution Approach 2:
The invention extends the attenuation capability from a single frequency region (near the pass band) to multiple frequency dimensions by introducing additional attenuation poles at higher frequencies. This multi-dimensional approach allows simultaneous optimization of attenuation in both low-frequency and high-frequency stop band regions.
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 layered low-pass filter effectively increases attenuation in multiple specific narrow frequency bands within the stop band by utilizing multiple attenuation poles, preventing an increase in insertion loss and allowing for adjustable pole frequencies, thus enhancing signal filtering capabilities without enlarging the filter size.
Implementation Method 1
Inverse Chebyshev low-pass filters and elliptic (simultaneous Chebyshev) low-pass filters are known as being capable of providing a steeper attenuation characteristic. The inverse Chebyshev low-pass filters and the elliptic low-pass filters present at least one attenuation pole in the stop band.
Data Source
AI summary
A layered low-pass filter includes: a first inductor and a second inductor that are connected in series and are located between an input terminal and an output terminal; a first capacitor connected in parallel to the first inductor; a second capacitor connected in parallel to the second inductor; and third to fifth capacitors and third to fifth inductors. The output of the first inductor and the input of the second inductor are connected to the ground via the third capacitor and the third inductor connected in series. The input of the first inductor is connected to the ground via the fourth capacitor and the fourth inductor connected in series. The output of the second inductor is connected to the ground via the fifth capacitor and the fifth inductor 8 connected in series.