Phased Antenna Array Cover Layer for Millimeter-Wave Signal Matching
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Solution Overview
Problem
Electronic devices face challenges in supporting millimeter and centimeter wave communications due to signal attenuation and distortion, as well as the generation of undesirable surface waves at medium interfaces, which affect antenna efficiency and signal propagation.
Innovation Solution
The implementation of a phased antenna array on a dielectric substrate with conductive traces forming antenna resonating and parasitic elements, mounted against a dielectric cover layer that acts as a quarter wave impedance transformer, and surrounded by conductive vias to enhance antenna gain and mitigate surface wave propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If antennas operate at millimeter and centimeter wave frequencies, then high bandwidth communication is enabled, but signal attenuation and distortion increase during propagation through dielectric media
Solution Approach 1:
A dielectric cover layer with specific impedance characteristics is introduced as an intermediary between the antenna array and the external environment. This layer acts as an impedance transformer that matches the high-impedance antenna elements to free space, reducing signal reflections and attenuation at the interface. The cover layer transforms the impedance of the antenna elements, enabling efficient energy transfer at millimeter and centimeter wave frequencies while minimizing losses in the dielectric medium.
2Volume of moving object
If antennas are mounted against a dielectric cover layer, then a compact device structure is achieved, but signal distortion and surface wave generation occur at the medium interface
Solution Approach 1:
The dielectric cover layer serves as a mediator that transforms the impedance of the antenna elements mounted against it. By selecting appropriate dielectric constant and thickness, the cover layer transforms the high impedance of the antenna elements to match free space impedance, reducing signal reflections and surface wave generation at the interface while maintaining compact device integration.
Solution Approach 2:
The patent employs parameter optimization of the dielectric cover layer, specifically adjusting the dielectric constant and thickness to achieve impedance transformation. The cover layer thickness is designed to be approximately one-quarter of the operating wavelength in the dielectric material, which transforms the impedance of the antenna elements and minimizes surface wave generation while maintaining compact form factor.
3Loss of energy
If the dielectric cover layer thickness is optimized for impedance transformation, then signal attenuation is minimized, but the layer must be precisely manufactured to specific dimensional tolerances
Solution Approach 1:
The patent optimizes the dielectric constant and thickness parameters of the cover layer to achieve impedance transformation. The thickness is designed to be approximately one-quarter of the operating wavelength in the dielectric material, which transforms the impedance of the antenna elements. While this requires precise manufacturing, the use of standard dielectric materials with known constants and established fabrication processes makes the precision requirements achievable in practice.
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 minimizes signal attenuation and destructive interference, ensuring satisfactory antenna gain across all angles and effective radio-frequency signal transmission through the dielectric cover layer, while preventing surface waves from escaping, thus improving wireless communication efficiency.
Implementation Method 1
The dielectric cover layer may have a dielectric constant and a thickness that is selected so that the dielectric cover layer forms a quarter wave impedance transformer for the phased antenna array at a wavelength of operation of the phased antenna array
Implementation Method 2
The substrate may include fences of conductive vias that laterally surround each of the antennas within the phased antenna array. The fences of conductive vias and ground traces in the substrate may define conductive cavities for each antenna in the phased antenna array
Implementation Method 3
The dielectric cover layer may have a dielectric constant and a thickness that is selected so that the dielectric cover layer forms a quarter wave impedance transformer for the phased antenna array at a wavelength of operation of the phased antenna array. When configured in this way, signal attenuation and destructive interference within and below the dielectric cover layer may be minimized
Data Source
AI summary
An electronic device may be provided with a dielectric cover layer, a dielectric substrate, and a phased antenna array on the dielectric substrate for conveying millimeter wave signals through the dielectric cover layer. The array may include conductive traces mounted against the dielectric layer. The conductive traces may form patch elements or parasitic elements for the phased antenna array. The dielectric layer may have a dielectric constant and a thickness selected to form a quarter wave impedance transformer for the array at a wavelength of operation of the array. The substrate may include fences of conductive vias that laterally surround each of the antennas within the array. When configured in this way, signal attenuation, destructive interference, and surface wave generation associated with the presence of the dielectric layer over the phased antenna array may be minimized.