Multilayer Wireless Module Ground Segmentation for RF Noise Isolation

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Solution Overview

Problem

Harmonic noise from an oscillation circuit component in a wireless module with an RFIC mounted on a multilayer substrate causes degradation in communication sensitivity due to direct flow through a ground pattern, affecting the RF circuit.

Innovation Solution

The ground patterns connected to the oscillation circuit and RFIC are separated in the conductor layer, forming a gap between them, preventing direct harmonic noise flow and allowing the RF circuit to maintain communication sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ground pattern immediately below the oscillation circuit component and RFIC is used to short-circuit ground terminals, then the ground potential is stabilized, but harmonic noise from the oscillation circuit flows into the RFIC through the ground pattern, degrading communication sensitivity

Engineering Contradiction:

Improveground potential stabilityVSAvoidharmonic noise interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ground pattern in the first conductor layer is divided into two separate segments: a first ground pattern connected to the first ground terminal of the oscillation circuit component, and a second ground pattern connected to the ground terminal of the RFIC. This segmentation prevents the direct flow of harmonic noise through the ground pattern while maintaining stable ground potential at each component location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary structure by separating the ground patterns and using different conductor layers to connect to the common ground. The first ground pattern and second ground pattern are separated in the first conductor layer but both connect to the common ground through the second conductor layer, acting as an intermediary that blocks noise propagation while maintaining ground stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If the oscillation circuit component and RFIC are mounted close together on the multilayer substrate, then the module size is reduced, but noise from the oscillation circuit interferes with the RFIC

Engineering Contradiction:

Improvemodule areaVSAvoidnoise interference

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes the vertical dimension of the multilayer substrate structure to solve the noise interference problem. By separating ground patterns in the first conductor layer and using the second conductor layer for common ground connection, the design allows close horizontal positioning of components while maintaining noise isolation through vertical layer separation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12483290B2Wireless module

Publication Date: 2025.11.25 TDK CORP

AI summary

Disclosed herein is a wireless module that includes an oscillation circuit component and an RFIC mounted on a multilayer substrate. The oscillation circuit component includes a clock terminal and a first ground terminal. The RFIC has a second ground terminal that supplies a ground potential to a clock circuit therein and a third ground terminal that supplies a ground potential to an RF circuit therein. The multilayer substrate includes a first conductor layer positioned closest to the plurality of pad electrodes of the RFIC and including a first ground pattern connected to the first and second ground terminals and a second ground pattern connected to the third ground terminal. The first and second ground patterns form a gap between the second and third ground terminals in a plan view as viewed in a stacking direction of the multilayer substrate.