RF Output Matching Inductor Layout for Higher Q Factor
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Solution Overview
Problem
Existing radio frequency modules face challenges in improving the Q factor of inductor parts within the output matching circuit connected to the power amplifier, which affects the module's performance.
Innovation Solution
The proposed radio frequency module includes a first and second wiring board, a power amplifier, and an output matching circuit with inductor parts arranged in a specific configuration to enhance the Q factor. The first inductor part closest to the output pad electrode is positioned on the first principal surface of the first wiring board, reducing parasitic capacitance and improving the Q factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the inductor part is arranged on the upper surface of the wiring board, then the layout is simple, but the Q factor deteriorates due to increased parasitic capacitance
Solution Approach 1:
The patent transitions the inductor arrangement from a two-dimensional surface layout to a three-dimensional configuration by extending the inductor across multiple wiring boards in the thickness direction. This dimensional change reduces parasitic capacitance between the inductor and ground, thereby improving the Q factor while maintaining layout simplicity through modular construction.
Solution Approach 2:
The inductor is divided into multiple segments arranged on different wiring boards (first wiring board and second wiring board). This segmentation allows each segment to be optimally positioned to minimize parasitic capacitance while maintaining the overall inductance value, resolving the contradiction between simple layout and high Q factor.
2Length of moving object
If the inductor part is arranged close to the output pad electrode, then the circuit length is reduced, but parasitic capacitance increases reducing the Q factor
Solution Approach 1:
The patent uses vertical stacking of wiring boards to maintain short electrical connection length while positioning the inductor segments in three-dimensional space away from high-capacitance areas. This allows the inductor to be electrically close (short circuit length) but physically arranged to minimize parasitic capacitance, improving Q factor.
3Reliability
If multiple wiring boards are used to improve Q factor, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The patent combines multiple wiring boards into a unified module structure where the first and second wiring boards are integrated with through-holes and conductive patterns that work together as a single functional unit. This merging approach reduces the perceived complexity by creating a cohesive multi-board assembly rather than separate components.
Solution Approach 2:
The wiring boards serve multiple functions: they provide mechanical support, electrical connections, and precise positioning for the inductor segments. The through-holes and conductive patterns perform both structural and electrical functions simultaneously, reducing overall device complexity while maintaining high Q factor.
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 effectively improves the Q factor of the inductor part, leading to enhanced performance of the radio frequency module by reducing energy loss and improving signal quality.
Implementation Method 1
at least part of a first inductor part is arranged on the first principal surface of the first wiring board, the first inductor part being an inductor part closest to the output pad electrode of the plurality of inductor parts
Data Source
AI summary
An output matching circuit includes a plurality of inductor parts and is connected to an output pad electrode of a power amplifier. In a radio frequency module, a second principal surface of a first wiring board and a third principal surface of a second wiring board are on opposite sides of the radio frequency module. An external connection terminal is arranged on a fourth principal surface of the second wiring board. The power amplifier is arranged on a first principal surface) of the first wiring board. In the output matching circuit, at least part of a first inductor part, which is the inductor part L1 closest to the output pad electrode of the plurality of inductor parts, is arranged on the first principal surface of the first wiring board.