Coaxial Waveguide Antenna Structure for Stable Passband and Return Loss
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Solution Overview
Problem
Conventional patch antennas experience irregular disturbances in pass amplitude and return loss characteristics due to element pattern variations and mutual interference, leading to decreased cutoff performance and unfavorable EVM values.
Innovation Solution
A coaxial waveguide conversion unit with a hexahedral structure and a conductive closure member, combined with a connector that protrudes into the waveguide to radiate radio waves within a specific frequency band, suppresses these disturbances and improves cutoff performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional patch antenna with multiple element patterns is used to cover a frequency band, then the frequency band coverage is improved, but irregular disturbances occur in pass amplitude and return loss characteristics due to element pattern variations and mutual interference
Solution Approach 1:
The patent divides the frequency band coverage into multiple independent frequency bands, each handled by a separate antenna element. This segmentation eliminates mutual interference between elements while maintaining broad frequency coverage, as each element operates independently without affecting the others' amplitude characteristics.
Solution Approach 2:
Each antenna element is designed with optimized local characteristics tailored to its specific frequency band. The patent applies different design parameters and structures to each element based on its operating frequency, ensuring optimal performance for each band while avoiding the disturbances caused by uniform multi-element designs.
2Adaptability or versatility
If multiple antenna elements are arranged on a substrate to match target frequency, then frequency band coverage is improved, but mutual interference between elements causes irregular disturbance in return loss characteristics
Solution Approach 1:
The patent segments the antenna system into spatially separated elements, each dedicated to a specific frequency band. This physical and functional segmentation eliminates mutual interference that would otherwise cause return loss disturbances, while the combined system maintains comprehensive frequency coverage.
Solution Approach 2:
The patent introduces an intermediary structure (substrate with optimized geometry and material properties) that mediates between the antenna elements and the environment. This intermediary minimizes coupling and interference between elements while maintaining their individual frequency-specific characteristics.
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 effectively reduces irregularities in pass amplitude and return loss characteristics, enhancing cutoff performance and achieving favorable EVM values by adapting the waveguide configuration to the specific frequency band.
Implementation Method 1
a radiator configured by the end portion of the center conductor protruding into the inner space, to radiate radio waves from the center conductor into the inner space by adapting the protruding length of the end portion to a specific frequency band
Data Source
Figure 1(a)~1(g)
Figure 2(a)~3(b)
Figure 4(a)~4(c)
AI summary
An object of the present invention is to suppress occurrence of disturbance in pass amplitude characteristics within a band and disturbance in return loss characteristics in the band due to total reflection, improve cutoff performance, and acquire a favorable gain. An antenna device 1 includes a waveguide body 5 including a coaxial waveguide conversion unit 6 that is hexahedral and includes an inner space 8 formed by penetrating a first surface and a second surface facing each other and a connector attachment hole 22 for inserting a coaxial connector continuously formed between a third surface orthogonal to the first surface and the second surface and the inner space, and a closure member 30 that is conductive and closes an opening of the inner space on the second surface side. The antenna device 1 also includes a connector 50 including a connector body 51 attached to the connector attachment hole from the inner space toward outside, with an inner end thereof not protruding into the inner space, a center conductor 60 arranged to axially penetrate a central portion of the connector body, with an end portion thereof protruding from an inner end of the connector body into the inner space by a predetermined length, and a radiator 54b configured by an end portion 60a of the center conductor that adapts the protruding length of the end portion to a specific frequency band.