Electronic Module Electrode Layout to Reduce Parasitic Capacitance

Solution Overview

Problem

Existing electronic modules with insulating layers covering peripheral electrodes suffer from degraded electrical characteristics due to increased electrostatic capacitance between signal and ground electrodes, leading to reduced signal transmission efficiency and impaired isolation characteristics.

Innovation Solution

The electronic module design features an insulating layer that does not cover the end portions of signal electrodes facing the ground electrode, allowing for increased spacing and reduced electrostatic capacitance, while also enhancing the ground electrode size and integration of ground terminal portions to reduce parasitic impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the peripheral portions of all electrodes are covered with an insulating layer, then the electrodes are protected from short-circuits, but the electrical characteristics of the electronic module degrade

Engineering Contradiction:

Improveprotection from short-circuitsVSAvoidelectrostatic capacitance between signal electrode and ground electrode

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The insulating layer is selectively applied to cover only specific portions of the electrodes rather than uniformly covering all electrodes. Specifically, the insulating layer covers peripheral portions of ground electrodes but intentionally leaves exposed the end portions of signal electrodes that face ground electrodes. This local differentiation allows the structure to simultaneously achieve protection from short-circuits while minimizing harmful electrostatic capacitance between signal and ground electrodes.

Inventive Principle:

Principle #3Local quality

2Reliability

If the insulating layer covers the end portion of the signal electrode facing the ground electrode, then the insulating layer provides comprehensive protection, but the space between signal electrode and ground electrode is reduced, increasing electrostatic capacitance

Engineering Contradiction:

Improveprotection from short-circuitsVSAvoidelectrostatic capacitance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The insulating layer is selectively applied to cover only specific portions of the electrodes rather than uniformly covering all electrodes. Specifically, the insulating layer covers peripheral portions of ground electrodes but intentionally leaves exposed the end portions of signal electrodes that face ground electrodes. This local differentiation allows the structure to simultaneously achieve protection from short-circuits while minimizing harmful electrostatic capacitance between signal and ground electrodes.

Inventive Principle:

Principle #3Local quality

3Reliability

If the ground electrode size is increased to enhance grounding, then the ground capability is improved, but the overall device area increases

Engineering Contradiction:

Improvegrounding capabilityVSAvoiddevice area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The insulating layer is selectively applied to cover only specific portions of the electrodes rather than uniformly covering all electrodes. Specifically, the insulating layer covers peripheral portions of ground electrodes but intentionally leaves exposed the end portions of signal electrodes that face ground electrodes. This local differentiation allows the structure to simultaneously achieve protection from short-circuits while minimizing harmful electrostatic capacitance between signal and ground electrodes.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes the vertical dimension by having the insulating layer extend in the thickness direction of the mount board to cover side surfaces of the ground electrode. This allows the ground electrode to achieve enhanced grounding capability through increased effective area in the vertical dimension rather than expanding horizontally, thus improving grounding without proportionally increasing the device footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 improves electrical characteristics by suppressing signal transmission via electrostatic capacitance, enhancing isolation, and maintaining high VSWR and surface flatness, resulting in superior performance in communication apparatuses like duplexer modules.

Implementation Method 1

the electrostatic capacitance generated between the signal electrode and the ground electrode can further be reduced

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

The insulating layer is located so as to cover a portion of the second main surface of the mount board

Methodology Applied

Scientific EffectInsulation: Dielectric

Data Source

PatentUS8797759B2Electronic module and communication apparatus

Publication Date: 2014.08.05 MURATA MFG CO LTD

AI summary

An electronic module with excellent electrical characteristics includes an electronic component, a mount board, signal electrodes, a ground electrode, and an insulating layer. The electronic component is mounted on a first main surface of the mount board. The signal electrodes and the ground electrode are located on a second main surface of the mount board. The insulating layer is arranged so as to cover a portion of the second main surface of the mount board. The insulating layer is arranged so as not to cover end portions of the signal electrodes that face the ground electrode.