Waveguide Conductive Rods for Impedance Matching at Bends
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Solution Overview
Problem
Waveguide devices with artificial magnetic conductors face impedance mismatching issues at bends and branching portions, leading to signal propagation loss and noise due to unwanted reflections.
Innovation Solution
The waveguide device incorporates conductive rods with tilted side faces, where the outer shape of the cross section monotonically decreases from the root to the leading end, enhancing impedance matching at bends and branching portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive rods with uniform cross-section are used at bends and branching portions, then the structure is simple and easy to manufacture, but impedance mismatching occurs causing signal reflection and propagation loss
Solution Approach 1:
The patent applies local quality by giving different cross-sectional shapes to different conductive rods based on their positions. Specifically, conductive rods adjacent to bends or branching portions have tilted side faces with monotonically decreasing outer shape from root to leading end, while other rods maintain uniform cross-sections. This localized structural differentiation improves impedance matching at critical locations without unnecessarily complicating the entire waveguide structure.
Solution Approach 2:
The patent changes the geometric parameters of conductive rods at specific locations to improve impedance matching. The outer shape parameter of the cross-section is modified to monotonically decrease from root to leading end for rods near bends or branching portions, creating a gradual transition that reduces impedance discontinuity and minimizes signal reflection.
2Reliability
If conductive rods with tilted side faces are used at bends and branching portions, then signal reflection is reduced and impedance matching is improved, but manufacturing complexity increases
Solution Approach 1:
The patent limits the tilted side face structure to only those conductive rods that are adjacent to bends or branching portions, while other rods maintain simple uniform cross-sections. This localized application reduces the overall manufacturing complexity while still achieving the primary goal of improving signal transmission quality at critical locations where impedance mismatching would otherwise occur.
3Productivity
If uniform conductive rods are used throughout the waveguide, then manufacturing is simple, but signal propagation loss increases at direction change portions
Solution Approach 1:
The patent implements local quality by differentiating the cross-sectional configuration of conductive rods based on their functional requirements. Rods at bends and branching portions have tilted side faces to minimize reflection and improve signal transmission efficiency, while rods in straight sections maintain uniform cross-sections. This selective differentiation reduces signal propagation loss at critical locations without unnecessarily increasing overall device complexity.
Solution Approach 2:
The patent modifies the geometric parameters of specific conductive rods to optimize signal transmission. The outer shape parameter changes monotonically from root to leading end for rods adjacent to direction changes, creating a gradual impedance transition that reduces reflection and improves signal transmission efficiency at bends and branching portions.
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 design improves impedance matching, reducing signal reflection and propagation loss, and enhances the performance of antenna devices by minimizing noise and power loss.
Implementation Method 1
A measure of an outer shape of a cross section of at least one of the plurality of conductive rods that is adjacent to the bend or the branching portion, taken perpendicular to an axial direction of the at least one conductive rod, monotonically decreases from a root that is in contact with the second conductive member toward the leading end
Implementation Method 2
An electromagnetic wave of a wavelength which is contained in the propagation-restricted band of the artificial magnetic conductor propagates along the ridge, in the space (gap) between this conductive surface and the upper face of the ridge
Implementation Method 3
An artificial magnetic conductor functions as a perfect magnetic conductor in a specific frequency band which is defined by its periodic structure. An artificial magnetic conductor restrains or prevents an electromagnetic wave of any frequency that is contained in the specific frequency band (propagation-restricted band) from propagating along the surface of the artificial magnetic conductor
Data Source
AI summary
A waveguide device includes: a first conductive member having an electrically conductive surface; a second conductive member having a plurality of electrically conductive rods arrayed thereon, each conductive rod having a leading end opposing the conductive surface; and a waveguide member having an electrically conductive waveguide face opposing the conductive surface, the waveguide member being disposed among the conductive rods and extending along the conductive surface. The waveguide member includes at least one of a bend and a branching portion. A measure of an outer shape of a cross section of at least one of the plurality of conductive rods that is adjacent to the bend or the branching portion, taken perpendicular to an axial direction of the at least one conductive rod, monotonically decreases from a root that is in contact with the second conductive member toward a leading end.