High-Pass Filter Stack for High-Q Miniaturized RF Circuits
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Solution Overview
Problem
Existing high-pass filters in compact mobile communication devices face challenges in maintaining a high Q value while minimizing size, as reducing inductor size leads to reduced inductance and Q value, and increasing inductance without size increase results in narrower conductor layers and through holes, affecting resonance frequency and performance.
Innovation Solution
A filter design incorporating multiple high-pass filters with parallel and serial capacitive elements and inductors, arranged in a stack with dielectric and conductor layers, allowing for increased capacitance to maintain desired resonance frequencies and Q values, and including through hole lines to enhance inductor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inductor size is reduced to miniaturize the branching filter, then the filter size is reduced, but the inductance and Q value of the inductor are reduced
Solution Approach 1:
The patent embeds a second capacitive element in parallel with the inductor and nests multiple high-pass filters within a compact stack configuration. This nesting approach allows the circuit to achieve the desired resonance frequency and Q value without increasing the physical size of the inductor, thereby miniaturizing the overall filter while maintaining performance
Solution Approach 2:
The patent changes the circuit parameters by introducing a second capacitive element in parallel with the inductor and configuring multiple high-pass filters with specific capacitance values. This parameter modification enables the system to achieve the target resonance frequency and maintain high Q value despite the reduced inductor size
2Reliability
If the inductance is increased without increasing filter size, then the resonance frequency can be adjusted, but the conductor layer widths and through hole diameters are reduced causing Q value to decrease
Solution Approach 1:
The patent modifies the circuit parameters by adding a second capacitive element in parallel with the inductor and configuring multiple high-pass filters with specific capacitance values. This allows the desired resonance frequency to be achieved without increasing the physical dimensions of the conductor layers and through holes, thereby maintaining manufacturing precision and Q value
3Adaptability or versatility
If multiple high-pass filters are integrated in a stack, then the filter functionality is enhanced, but the device complexity increases
Solution Approach 1:
The patent combines multiple high-pass filters into a single integrated stack configuration, merging their functions into one compact unit. This consolidation enhances the overall filter functionality while managing device complexity through unified structural design
Solution Approach 2:
The stack configuration of multiple high-pass filters provides multi-functionality, enabling the filter to handle various frequency bands and signal types. This universal design allows a single device to perform multiple filtering functions simultaneously
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 design achieves increased Q value of inductors, reduces insertion loss, and enhances pass attenuation in lower frequency bands, maintaining desired filter characteristics despite miniaturization.
Implementation Method 1
a first resonance frequency of a serial circuit including the inductor and a capacitor that corresponds to the first capacitive element and a second resonance frequency of a parallel circuit including the inductor and the second capacitive element
Data Source
AI summary
A filter includes a first port, a second port, and a high-pass filter provided between the first port and the second port in a circuit configuration. The high-pass filter includes a first capacitive element provided in a path connecting the first port and the second port, an inductor provided between the path and the ground, and a second capacitive element connected in parallel with the inductor.