Magnetically Coupled High-Pass Filter for Wideband Low Insertion Loss
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Solution Overview
Problem
Existing high pass filter circuits suffer from parasitic capacitances that cause self-resonance in inductors, leading to suppressed signal passage in higher frequency bands and narrow pass bands, which is inadequate for modern applications requiring low insertion loss over wide frequency bands such as 5G and UWB.
Innovation Solution
The proposed filter configuration includes a first capacitor connected in series between terminal pairs, a first inductor connected in parallel with the capacitor, and a second inductor connected in parallel between the terminal pairs, with the first and second inductors being magnetically coupled and differentially connected, effectively managing parasitic capacitances and maintaining bandpass characteristics in high frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LC series resonant circuits are formed with inductors and capacitors in a high pass filter, then the filter provides frequency selectivity, but parasitic capacitances cause self-resonance in the inductors which suppresses signal passage in higher frequency bands
Solution Approach 1:
The patent converts the harmful parasitic capacitance effect into a beneficial feature by intentionally introducing parasitic capacitance elements in parallel with the inductors. This creates a controlled self-resonance that actually improves the filter's high-frequency performance rather than degrading it, allowing the filter to maintain signal passage in higher frequency bands where conventional filters would fail.
2Device complexity
If conventional high pass filter circuits are used, then the circuit structure is simple, but the pass band becomes narrow and insertion loss increases in higher frequency bands
Solution Approach 1:
The patent changes the electrical parameters of the filter circuit by introducing parasitic capacitance elements with specific capacitance values (Cp1, Cp2) in parallel with the inductors. This parameter modification transforms the filter's frequency response characteristics, enabling low insertion loss performance in higher frequency bands while maintaining a relatively simple circuit structure with only two additional capacitor elements.
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 achieves low insertion loss even in higher frequency bands, preventing degradation of bandpass characteristics due to parasitic capacitances, and allows for downsizing and increased Q factors of the inductors, resulting in improved filter performance.
Implementation Method 1
The first inductor and the second inductor are magnetically coupled to each other and are differentially connected to each other
Data Source
AI summary
A filter includes a first capacitor connected in series between a first terminal pair and a second terminal pair, a first inductor connected in parallel with the first capacitor, and a second inductor connected in parallel between the first terminal pair and the second terminal pair. The first inductor and the second inductor are magnetically coupled to each other and are differentially connected to each other.