Waveguide Converter Vertical Stacking for Antenna Grating Lobes
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Solution Overview
Problem
Existing waveguide/transmission line converters result in oversized antenna devices with wider distances between antenna elements, leading to potential grating lobes and reduced directivity, especially during beam scanning to a wide field of view.
Innovation Solution
A waveguide/transmission line converter design with a dielectric substrate, short-circuit metal layer, and matching element, where the short-circuit metal layer is only along the wide walls of the waveguide, reducing the size of the converter and minimizing electromagnetic wave radiation, and incorporating a dielectric layer to increase the effective dielectric constant and reduce pattern sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a waveguide short-circuit surface is placed at a position distant from the transmission line by approximately 1/4 wavelength, then power conversion between waveguide and transmission line is achieved, but the antenna device size increases and directivity deteriorates
Solution Approach 1:
The patent transitions from a conventional planar layout to a three-dimensional stacked configuration. The transmission line is positioned above the waveguide with a ground layer in between, utilizing the vertical dimension to achieve compact integration while maintaining the required electrical performance for power conversion.
Solution Approach 2:
The patent embeds multiple functional layers within a compact vertical structure. The ground layer is nested between the waveguide and transmission line, creating a nested configuration that achieves both power conversion and compact size without requiring distant placement of components.
2Reliability
If a waveguide short-circuit surface is placed at a position distant from the transmission line by approximately 1/4 wavelength, then power conversion between waveguide and transmission line is achieved, but antenna element spacing increases causing grating lobes
Solution Approach 1:
By utilizing the vertical dimension with the ground layer stacked between waveguide and transmission line, the patent achieves compact horizontal spacing between antenna elements while maintaining the electrical length required for effective power conversion, thereby avoiding grating lobes.
Solution Approach 2:
The patent changes the physical configuration parameters by introducing a ground layer with specific dielectric properties and thickness, which modifies the effective electrical length and impedance characteristics, enabling compact spacing while maintaining power conversion efficiency.
3Length of stationary object
If the converter size is reduced by eliminating the distant short-circuit surface, then antenna element spacing decreases improving directivity, but power conversion efficiency may deteriorate
Solution Approach 1:
The ground layer serves as an intermediary between the waveguide and transmission line, enabling electromagnetic coupling and power conversion while maintaining a compact vertical structure. This intermediary layer with controlled dielectric properties ensures efficient power transfer without requiring distant component placement.
Solution Approach 2:
The patent achieves compact size by moving the coupling mechanism to the vertical dimension through the ground layer, eliminating the need for distant horizontal placement of short-circuit surfaces while maintaining power conversion efficiency through the stacked configuration.
4Reliability
If conventional waveguide/transmission line converter structure is used, then power conversion is achieved, but the structure complexity increases with additional metal layers and components
Solution Approach 1:
The patent merges multiple functions into a single integrated stacked structure. The ground layer simultaneously serves as a reference plane, coupling element, and shielding layer, while the vertical integration of waveguide, ground layer, and transmission line eliminates the need for separate distant short-circuit surfaces and reduces overall structural complexity.
Solution Approach 2:
The ground layer performs multiple functions including providing a reference potential plane, enabling electromagnetic coupling between waveguide and transmission line, and acting as a shield. This multi-functional design reduces the number of separate components needed, simplifying the overall converter structure.
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
The solution reduces the size of the waveguide converter, narrows the distance between antenna elements, and minimizes grating lobes, enabling high-gain directivity across a wide frequency range and improved beam scanning capabilities.
Implementation Method 1
a resonant length adapted to set up, as a standing wave, an electromagnetic wave having an effective wavelength
Implementation Method 2
incorporating a dielectric layer to increase the effective dielectric constant and reduce pattern sizes
Data Source
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AI summary
The present disclosure is directed to providing: a waveguide/transmission line converter in which a size in a direction along a cross-section of a wide wall of a waveguide out of sizes of patterns arranged on a surface of a dielectric substrate is reduced; and an antenna device in which a distance between antenna elements in respective columns adjacent to each other is narrowed and grating lobe(s) hardly occur(s) in directivity of the array antenna formed of the respective antenna elements constituting the respective columns, particularly at the time of adjusting phase information of respective antenna elements and performing beam scanning to a wide field of view. According to the present disclosure, a metal member 15 which allows a waveguide 11 to extend inside a dielectric substrate 13 and is adapted to hold a short-circuit metal layer 14 at a potential same as a potential of the waveguide 11 is made to remain along cross-sections of the two wide walls of the waveguide 11 and is removed along cross-sections of two narrow walls of the waveguide 11 so as to prevent an electromagnetic wave from unintendedly being radiated.