Filter Module Floating Wiring for Magnetic Coupling Cancellation
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Solution Overview
Problem
The degradation of attenuation characteristics in filter modules due to magnetic coupling between inductors and wiring, which affects high-frequency signal transmission, is not effectively addressed by existing technologies, even with the use of shield wiring.
Innovation Solution
Incorporating a second wiring with direct-current floating potential between the inductor and the first wiring, which is capacitively coupled to the first wiring, allowing for adjustment of the phase and amplitude of high-frequency components to cancel out the degradation caused by magnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shield wiring connected to ground is arranged between the inductor and the filter, then the high-frequency component from magnetic coupling can escape to ground, but the inductor and the filter wiring are still magnetically coupled in significant quantities causing degradation in attenuation characteristics
Solution Approach 1:
A capacitor is introduced as an intermediary element connected between the shield wiring and ground. This capacitor provides a controlled impedance path that allows the high-frequency components from magnetic coupling to be diverted to ground through the capacitor, rather than directly through the shield wiring connection. The capacitor's reactance at high frequencies creates an effective ground path for the harmful high-frequency components while maintaining the shielding function.
Solution Approach 2:
The electrical parameters of the shielding system are changed by introducing a capacitor with specific capacitance value. This changes the impedance characteristics of the shield wiring connection to ground, transforming it from a direct low-impedance path to a frequency-dependent path. The capacitor value is selected to provide optimal high-frequency attenuation while maintaining proper DC grounding of the shield.
2Volume of moving object
If the inductor and the filter are positioned closely, then the device size is reduced, but the inductor and the filter wiring are magnetically coupled causing degradation in attenuation characteristics
Solution Approach 1:
The capacitor connected between the shield wiring and ground acts as an intermediary that absorbs and redirects magnetic coupling effects. By providing a dedicated path through the capacitor for high-frequency magnetic coupling components, the system can tolerate closer positioning of the inductor and filter without allowing these harmful components to degrade filter attenuation characteristics.
Solution Approach 2:
The magnetic coupling between the inductor and filter wiring, which is normally harmful, is converted into a beneficial effect by directing it through the capacitor to ground. The high-frequency components generated by magnetic coupling are now channeled through the capacitor's reactance to ground, where they are dissipated, effectively using the coupling effect against itself rather than allowing it to degrade filter performance.
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 improves the attenuation characteristics of the filter module by effectively canceling out high-frequency components, leading to enhanced isolation and performance in frequency ranges like Band 26 Tx.
Implementation Method 1
the inductor and the first wiring are magnetically coupled, the inductor and the second wiring are magnetically coupled
Implementation Method 2
the first wiring and the second wiring are capacitively coupled
Data Source
AI summary
A filter module includes an inductor, a filter including first wiring, and second wiring between the inductor and the first wiring and being a direct-current floating potential. The inductor and the first wiring are magnetically coupled, the inductor and the second wiring are magnetically coupled, and the first wiring and the second wiring are capacitively coupled.