Multi-Layer Substrate Antenna Arrays for Millimeter Wave Isolation
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Solution Overview
Problem
Existing electronic devices face challenges in isolating transmission lines for millimeter wave communications while maintaining compact structures, which is essential for small form factor wireless devices, as high permittivity materials can lead to electromagnetic interference and reduced bandwidth.
Innovation Solution
The use of a substrate with alternating dielectric layers of high and low permittivity, where the phased antenna array is formed on the low permittivity layers and the transmission lines are on the high permittivity layers, allowing for closer routing of transmission lines without interference and maintaining antenna efficiency and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If transmission lines are routed far apart from each other, then electromagnetic isolation between transmission lines is improved, but device volume increases
Solution Approach 1:
The patent applies local quality by using different dielectric materials with different permittivity values in different regions of the substrate. Specifically, high permittivity dielectric material is used in regions where transmission lines are routed close together to provide electromagnetic isolation, while low permittivity dielectric material is used in regions where antennas are placed to maintain antenna efficiency. This spatial variation of material properties allows the device to achieve both compact size and electromagnetic isolation without increasing overall device volume.
2Object-affected harmful factors
If high permittivity dielectric material is used for transmission lines, then transmission line isolation is improved, but antenna efficiency decreases
Solution Approach 1:
The patent implements local quality by assigning different dielectric materials to different functional regions: high permittivity material (e.g., ceramic-filled epoxy with εr≈7-10) is used beneath transmission lines to provide electromagnetic confinement and isolation, while low permittivity material (e.g., foam or air-filled regions with εr≈1.05-2.0) is used in the antenna region to minimize dielectric losses and maintain radiation efficiency. The substrate structure may include multiple layers with varying dielectric properties, allowing each region to be optimized for its specific function.
Solution Approach 2:
The patent employs composite materials by combining different dielectric materials with contrasting permittivity values within a single substrate structure. The substrate may consist of layers comprising ceramic-filled epoxy, foam materials, or air-filled regions, creating a composite structure that leverages the advantages of each material: high permittivity materials for transmission line isolation and low permittivity materials for antenna efficiency. This composite approach enables simultaneous optimization of both transmission and radiation functions.
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 enables efficient millimeter wave communications by minimizing electromagnetic interference between transmission lines while allowing for compact device designs, enhancing antenna performance and bandwidth without increasing device volume.
Implementation Method 1
The substrate may include a first set of dielectric layers (e.g., one or more dielectric layers) having a first dielectric permittivity and a second set of dielectric layers (e.g., one or more dielectric layers) having a second dielectric permittivity that is less than the first dielectric permittivity
Implementation Method 2
The relatively low permittivity of the second set of dielectric layers may allow the phased antenna array to operate with satisfactory antenna efficiency, gain, and bandwidth
Data Source
AI summary
An electronic device may be provided with a phased antenna array for conveying millimeter wave signals. The array may be mounted to a substrate that includes transmission line layers having a first dielectric permittivity and antenna layers having a second dielectric permittivity that is less than the first dielectric permittivity. A ground plane may be interposed between the antenna layers and the transmission line layers. The array may be mounted to the antenna layers and transceiver circuitry may be mounted to the transmission line layers. Transmission line traces may be formed on the transmission line layers. The relatively high permittivity of the first set of dielectric layers may allow the transmission line traces to be routed relatively close together with minimal electromagnetic interference. The relatively low permittivity of the second set of dielectric layers may allow the array to operate with satisfactory antenna efficiency, gain, and bandwidth.