Millimeter-Wave Antenna Coupling via Proximity Post

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Solution Overview

Problem

Existing millimeter-wave antenna arrays in communication devices, such as smartphones, face challenges in integration due to size and design constraints, requiring placement on the outer borders and significant modifications to achieve acceptable performance.

Innovation Solution

A coupling and re-radiating system using a hollowed section with a below-cutoff cavity and a metallic proximity post to excite an evanescent electromagnetic field, allowing for compact integration and flexible design without compromising the industrial design of the device, enabling efficient RF energy transfer and re-radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If embedded millimeter-wave antenna arrays are placed on the outer borders of the device, then antenna radiation performance is achieved, but device size and thickness are significantly restricted and industrial design must be considerably modified

Engineering Contradiction:
Improveantenna radiation performanceVSAvoiddevice size and thickness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

A coupling structure is introduced as an intermediary between the antenna array and the device housing. This coupling structure includes a first portion that couples to the antenna array and a second portion that extends to the outer surface of the device, enabling the antenna to radiate effectively without being positioned at the extreme outer border, thus preserving both radiation performance and industrial design flexibility

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling structure extends in the depth dimension (from the antenna array toward the outer surface) rather than requiring the antenna array itself to be positioned at the outer border. This dimensional approach allows the antenna to be embedded deeper within the device while still achieving effective radiation through the coupling structure's extension

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If embedded millimeter-wave antenna arrays are integrated into the device, then wireless communication functionality is achieved, but significant modification and trimming of the industrial design is required

Engineering Contradiction:
Improvewireless communication functionalityVSAvoidindustrial design modification
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The coupling structure serves as a flexible intermediary that can be adapted to various industrial design configurations. By positioning the antenna array internally and using the coupling structure to bridge to the outer surface, the design allows for easier integration without requiring extensive modifications to the device housing or trim pieces

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the device housing is made transparent or translucent, then the coupling structure can be concealed, but the structural integrity and RF performance may be compromised

Engineering Contradiction:
Improveconcealment of coupling structureVSAvoidstructural integrity and RF performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The coupling structure is designed with differentiated portions: a first portion that interfaces with the antenna array and can be made from RF-transparent or translucent material to maintain concealment, and a second portion that extends to the outer surface and can be made from a different material optimized for structural integrity and radiation efficiency. This local differentiation allows each portion to optimize for its specific functional requirements

Inventive Principle:
Principle #3Local quality

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 solution provides wide-angle antenna performance within size constraints, facilitating customizable antenna solutions and achieving 5G millimeter-wave spherical coverage without imposing restrictions on the device's industrial design.

Implementation Method 1

a millimeter-wave antenna element located at the inner opening of the cavity only excites an evanescent electromagnetic field in the below-cutoff cavity

Methodology Applied
Scientific EffectEvanescent electromagnetic field:

Implementation Method 2

A metallic proximity post has a first section positioned adjacent and spaced apart from the millimeter-wave antenna element to couple to, and conduct, energy from the evanescent electromagnetic field

Methodology Applied
Scientific EffectEvanescent field coupling:

Data Source

PatentEP3703184B1Coupling and re-radiating system for millimeter-wave antenna
Publication Date: 2022.06.29 MOTOROLA MOBILITY LLC
  • EP3703184B1 patent drawingFigure 1
  • EP3703184B1 patent drawingFigure 2
  • EP3703184B1 patent drawingFigure 3

AI summary

An antenna subsystem of a communication device has an open cavity including an inner opening and lateral and outer sides that define a cavity. The cavity is sized less than required for cavity mode resonance at a millimeter-wave operating frequency. A millimeter-wave antenna element placed at the inner opening of the hollowed section cavity excites evanescent electromagnetic fields in the cavity. A slot antenna is formed in a metallic layer of the outer side of the cavity. A metallic sectioned proximity post has a first section positioned adjacent to and spaced apart from the millimeter-wave antenna element to couple to, and conduct, the evanescent electromagnetic field. The metallic proximity post has a second section positioned adjacent to and spaced apart from the slot antenna to couple at the millimeter-wave operating frequency, enabling re-radiation by the slot antenna.