Multilayer Antenna Module Layout to Reduce Substrate Warpage

Solution Overview

Problem

In antenna modules with multilayer substrates, unbalanced residual copper ratios between dielectric layers cause warpage due to differential deformation under stress, affecting antenna characteristics and reliability.

Innovation Solution

The introduction of peripheral electrodes in multiple layers between radiating elements and the ground electrode increases the residual copper ratio in the antenna region, reducing warpage by balancing the copper ratio and enhancing coupling between the radiating elements and the ground electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elements including feed lines and connection wires are formed in a dielectric layer below the ground electrode to reduce coupling with radiating elements, then antenna characteristics are improved, but the residual copper ratio becomes unbalanced causing warpage in the dielectric substrate

Engineering Contradiction:

Improveantenna characteristicsVSAvoidwarpage of dielectric substrate

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by forming a copper foil layer specifically in the antenna region (second region) between the ground electrode and radiating element. This localized copper addition balances the residual copper ratio without affecting the wiring region structure, thereby preventing warpage while maintaining the electrical isolation needed for good antenna characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by forming the copper foil layer in the antenna region before the lamination process. This advance preparation ensures that when the dielectric substrate is laminated and subjected to thermal and mechanical stresses, the residual copper ratio is already balanced, preventing warpage from occurring in the first place

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the residual copper ratio in the antenna region is lower than in the wiring region, then coupling with radiating elements is reduced, but differential deformation under stress causes warpage

Engineering Contradiction:

Improveantenna characteristicsVSAvoiduniformity of dielectric layer deformation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by forming a copper foil layer specifically in the antenna region (second region) between the ground electrode and radiating element. This localized copper addition balances the residual copper ratio without affecting the wiring region structure, thereby preventing warpage while maintaining the electrical isolation needed for good antenna characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent achieves homogeneity by adding copper foil to the antenna region to match the residual copper ratio of the wiring region. This creates uniform copper distribution across all dielectric layers, ensuring that all layers deform equally under thermal and mechanical stress during lamination, thereby eliminating warpage

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS12003015B2Antenna module, manufacturing method thereof, and collective board

Publication Date: 2024.06.04 MURATA MFG CO LTD

AI summary

An antenna module including a dielectric substrate formed by stacking a plurality of dielectric layers, a radiating element formed on or in the dielectric substrate, a ground electrode facing the radiating element, and peripheral electrodes that are formed in a plurality of layers between the radiating element and the ground electrode at an outer periphery of the dielectric substrate.