RF Module Multilayer Inductor Layout for Low Inter-Band Coupling
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Solution Overview
Problem
Radio-frequency modules face challenges in suppressing coupling between inductor portions in different frequency bands, leading to unwanted radiation and degraded reception performance when harmonic waves from one frequency band overlap with another, particularly in simultaneous communication scenarios like carrier aggregation or dual connectivity.
Innovation Solution
The radio-frequency module incorporates a multilayer substrate with inner-layer inductors and chip inductors, along with a ground layer, to minimize magnetic coupling between the first and second matching circuits, thereby reducing unwanted radiation and maintaining reception performance across different frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If inductor portions from different frequency bands are placed close to each other on the same layer, then device area is reduced, but magnetic coupling between the inductors increases causing unwanted radiation
Solution Approach 1:
The patent moves the first inductor portion from the surface layer to an inner layer of the substrate, creating a three-dimensional spatial separation. This vertical dimensionality change allows the inductor to be positioned beneath the surface where it can be closer to other components in terms of device footprint while maintaining electromagnetic isolation through the substrate layers, thus reducing magnetic coupling and unwanted radiation.
Solution Approach 2:
The patent embeds the first inductor portion within the substrate structure itself, nesting it in an inner layer surrounded by substrate material. This nesting approach allows the inductor to be integrated into the device volume rather than occupying surface area, enabling compact layout while the surrounding substrate provides electromagnetic shielding that reduces coupling with other inductors.
2Object-generated harmful factors
If inductor portions are separated to reduce magnetic coupling, then unwanted radiation is suppressed, but device area increases
Solution Approach 1:
By utilizing the vertical dimension through inner layer placement, the patent achieves electromagnetic separation equivalent to large horizontal distances without increasing the device footprint. The third-dimensional positioning allows compact surface layout while maintaining the isolation benefits of separation through substrate thickness and layered structure.
Solution Approach 2:
The nested configuration within substrate layers allows multiple inductors to be packed closely in the planar dimensions while the substrate structure itself provides the separation medium. This nesting enables high component density on the surface while the embedded inductor in inner layers remains isolated through the substrate material.
3Device complexity
If multiple frequency band circuits are integrated on the same substrate, then device complexity is reduced, but coupling between different frequency bands increases
Solution Approach 1:
The patent uses vertical layering to separate circuits operating at different frequency bands, placing sensitive low-band circuits in inner layers and high-band circuits on the surface. This three-dimensional arrangement maintains a compact integrated design while providing electromagnetic isolation between frequency bands through the substrate layers, reducing inter-band coupling.
Solution Approach 2:
The patent embeds low-band circuits within the substrate structure in inner layers, nesting them beneath the high-band surface circuits. This nested integration allows multiple frequency band circuits to coexist in a compact package while the substrate material provides natural shielding that reduces coupling between the nested low-band and surface high-band circuits.
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 suppresses unwanted radiation and maintains improved communication performance by reducing magnetic coupling between inductor portions, ensuring effective signal transmission and reception across multiple frequency bands during simultaneous communication.
Implementation Method 1
minimize magnetic coupling between the first and second matching circuits
Data Source
AI summary
A first power amplifier amplifies first transmission signals in a first frequency band and outputs the resultant signals. A first matching circuit includes a plurality of first inductor portions and is connected to an output pad electrode of the first power amplifier. A second power amplifier amplifies second transmission signals in a second frequency band higher than the first frequency band and outputs the resultant signals. A second matching circuit includes at least one second inductor portion and is connected to an output side of the second power amplifier. A multilayer substrate has a first main surface and a second main surface located opposite to each other and is provided with the first and second power amplifiers and the first and second matching circuits. The first inductor portion closer than the other first inductor portions to the output pad electrode includes an inner-layer inductor portion located in the multilayer substrate.