Filter Circuit Module With Phase-Shift Trap for 2.4-GHz Loss Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing filter circuit designs for communication modules suffer from increased transmission loss due to the inclusion of LC parallel resonant circuits in series with the signal line, which is not effective in attenuating 2.4-GHz band interfering waves without significant signal loss.
Innovation Solution
A filter circuit module with a shunt-connected LC parallel resonant circuit and a phase-shift circuit, where the LC parallel resonant circuit is connected in parallel with a second inductor, and a capacitor-between-input-and-output is used to trap the 2.4-GHz frequency, minimizing transmission loss by shifting the phase of the signal to ground, thereby acting as a trap filter for the 2.4-GHz band and attenuating harmonic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an LC parallel resonant circuit is provided in series to a transmission line to attenuate 2.4-GHz band interfering waves, then the attenuation of signals in the specific frequency band is improved, but the transmission loss of signals is increased
Solution Approach 1:
The filter circuit is divided into two independent parts: a first filter circuit (LC parallel resonant circuit) for attenuating 2.4-GHz band interfering waves, and a second filter circuit (notch filter) for attenuating harmonic components. This segmentation allows each circuit to be optimized for its specific function, enabling effective interference attenuation while minimizing overall transmission loss through proper design of each segment.
Solution Approach 2:
A phase-shift circuit is introduced as an intermediary component between the input and output of the filter circuit module. This phase-shift circuit compensates for the phase distortion caused by the LC parallel resonant circuit, thereby reducing the impact on signal transmission quality and minimizing transmission loss while maintaining effective attenuation of interfering waves.
2Object-affected harmful factors
If traditional filter circuit designs are used to attenuate harmonic components, then the suppression of harmonic waves is improved, but the number of components and module size increase
Solution Approach 1:
The second filter circuit is designed as a notch filter that serves multiple functions: it attenuates harmonic components of the input signal and simultaneously provides phase shifting functionality. This multi-functionality reduces the need for separate components, thereby decreasing the overall number of components and reducing module size while maintaining effective harmonic suppression.
Solution Approach 2:
The phase-shift circuit is merged with the second filter circuit (notch filter) into a single integrated structure. This merging combines the harmonic attenuation function and the phase shifting function into one component, reducing the total component count and simplifying the overall circuit architecture while achieving both objectives effectively.
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 solution effectively attenuates signals in the 2.4-GHz band and its harmonics with minimal transmission loss, providing improved signal trapping and harmonic suppression compared to traditional designs, while reducing the number of components and module size.
Implementation Method 1
The phase-shift circuit includes a primary coil, a secondary coil, and a capacitor-between-input-and-output. The primary coil is magnetically coupled to the secondary coil.
Implementation Method 2
The LC parallel resonant circuit includes the second inductor and the resonant circuit capacitor connected in parallel to the second inductor. The attenuation pole frequency of the filter 94 is set, for example, so as to be equal to or substantially equal to the frequency of a second harmonic signal
Data Source
AI summary
A filter circuit module includes a filter circuit element, a circuit board with the filter circuit element mounted thereon, and a first inductor. The filter circuit element includes a resonant circuit capacitor defining a portion of an LC parallel resonant circuit, and a phase-shift circuit. The circuit board includes a second inductor. A primary coil and a secondary coil of the phase-shift circuit are overlapped with the second inductor, viewed in a direction of a winding axis. The resonant circuit capacitor is closer to a mounting surface on which the filter circuit element is mounted on the circuit board, compared with the primary coil and the secondary coil. The resonant circuit capacitor includes a capacitor electrode covering a coil opening of the primary coil and a coil opening of the secondary coil, viewed in the direction of the winding axis.