SAW Filter Matching Coupling for Compact RF Attenuation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-frequency filter circuits for mobile devices require additional components like inductors or capacitors to improve attenuation characteristics, leading to increased size and complexity, which is not suitable for compact mobile terminals.
Innovation Solution
A high-frequency module with a compact filter circuit design that uses inductive or capacitive coupling between filter elements and matching elements to adjust transmission characteristics without additional inductors or capacitors, allowing for improved attenuation characteristics outside the pass band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a correction circuit including an inductor or a series circuit including an inductor and a capacitor is connected in parallel to the series circuit of SAW filters, then attenuation characteristics outside the pass band are improved, but the number of components increases and the size of the filter circuit increases
Solution Approach 1:
The patent combines the matching element functions (inductor and capacitor) into a single integrated component that is connected in parallel with the series circuit of SAW filters. This single matching element performs both the inductive and capacitive functions needed for attenuation correction outside the pass band, thereby reducing the total number of components while maintaining the desired attenuation characteristics.
2Reliability
If a correction circuit including an inductor or a series circuit including an inductor and a capacitor is connected in parallel to the series circuit of SAW filters, then attenuation characteristics outside the pass band are improved, but the size of the filter circuit increases
Solution Approach 1:
The patent merges multiple discrete components (inductor and capacitor) into a single integrated matching element, which significantly reduces the physical space required for the filter circuit while maintaining the attenuation correction function outside the pass band.
3Reliability
If additional inductors or capacitors are used to adjust transmission characteristics, then attenuation characteristics outside the pass band are improved, but the device complexity and component count increase
Solution Approach 1:
The matching element is designed to perform multiple functions simultaneously: it provides both inductive and capacitive reactance to correct attenuation characteristics outside the pass band, while also serving as a single adjustable component for tuning the transmission characteristics of the filter circuit.
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 enables adjustment of attenuation characteristics and impedance outside the pass band without affecting the desired frequency band, resulting in a more compact and efficient filter circuit.
Implementation Method 1
The matching element is inductively coupled or capacitively coupled to at least one of a connection unit at one end that connects a filter element at one end among the plurality of filter elements to the first terminal
Implementation Method 2
The matching element is inductively coupled or capacitively coupled to at least one of a connection unit at one end that connects a filter element at one end among the plurality of filter elements to the first terminal
Data Source
AI summary
A high-frequency module includes a filter unit and first and second external connection terminals. The filter unit includes first and second terminals and a plurality of SAW resonators. The plurality of SAW resonators are connected to one another by connection conductors. A matching element is connected between the first terminal and the first external connection terminal, and a matching element is connected between the second terminal and the second external connection terminal. At least one of the matching elements is inductively coupled or capacitively coupled to at least one of the connection conductors located at a position such that at least one of the SAW resonators is interposed between the matching element and the connection conductor.