SAW High-Frequency Module With Coupled Matching for Out-of-Band Attenuation
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Solution Overview
Problem
Existing high-frequency filter circuits for portable devices require additional components like inductors or capacitors to improve attenuation characteristics, increasing the circuit size and complexity, which is not suitable for compact portable terminals.
Innovation Solution
A high-frequency module with a filter unit and a matching circuit that uses inductive or capacitive coupling between the filter unit and an inductor to create an auxiliary propagation path, allowing for adjustment of transfer characteristics without additional components, thereby improving attenuation characteristics outside the passband.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inductor or compensation circuit is added to improve attenuation characteristics, then the attenuation performance outside passband is improved, but the circuit size and complexity increase
Solution Approach 1:
The patent combines the matching circuit and the inductor into a single integrated structure where the inductor serves dual purposes: as part of the matching circuit for impedance matching and as an attenuation enhancement element. This merging eliminates the need for separate compensation circuits while achieving both impedance matching and improved attenuation characteristics.
Solution Approach 2:
The inductor in the patent performs multiple functions simultaneously: it provides impedance matching between the filter unit and transmission line, and it enhances attenuation characteristics outside the passband. This multi-functionality reduces the total number of components needed while achieving multiple performance goals.
2Reliability
If an inductor or compensation circuit is added to improve attenuation characteristics, then the attenuation performance outside passband is improved, but the circuit size increases
Solution Approach 1:
The patent merges the matching circuit and inductor into a single integrated structure, reducing the total component count and overall circuit footprint. The inductor is positioned to serve both matching and attenuation functions, eliminating the need for separate compensation circuits and reducing circuit size.
3Reliability
If additional components are provided to improve attenuation characteristics, then the attenuation performance is improved, but the number of constituent elements increases
Solution Approach 1:
The inductor is designed to perform multiple functions: impedance matching and attenuation enhancement. By making this single component multi-functional, the patent avoids adding separate compensation circuits or additional components, thus maintaining a low component count while achieving improved attenuation characteristics.
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 without affecting the passband, resulting in a smaller, more efficient filter circuit with improved performance, reducing the need for additional components like inductors or capacitors.
Implementation Method 1
The inductor and the matching circuit are inductively or capacitively coupled to each other
Implementation Method 2
The inductor and the matching circuit are inductively or capacitively coupled to each other
Implementation Method 3
a plurality of series-connected filter elements connected in series between the first series connection terminal and the second series connection terminal
Data Source
AI summary
A high-frequency module includes a connection line that interconnects a first SAW resonator and a second SAW resonator, and is connected to a second shunt connection terminal through a third SAW resonator. A connection line interconnecting a fourth SAW resonator and a second series connection terminal is connected to the second shunt connection terminal through a fifth SAW resonator. The second shunt connection terminal is connected to a ground through an inductor. A matching circuit is connected between a first series connection terminal and a first external connection terminal. The matching circuit is inductively or capacitively coupled to the inductor.