Coaxial Microstrip Waveguide Transition for Signal Leakage
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Solution Overview
Problem
The existing methods for connecting coaxial connectors and microstrip lines in electronic devices, such as radar and communication equipment, suffer from signal leakage and stress concentration due to temperature-induced deformation, leading to reliability issues.
Innovation Solution
A coaxial microstrip line conversion circuit is designed with a waveguide having through holes that cut off transmission frequencies, a coaxial line with a projection extending beyond its outer conductor, and a microstrip line with a projection extending beyond its ground conductor, ensuring electrical isolation and preventing mechanical stress at the connection point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a gap is provided between the housing and substrate to accommodate thermal expansion differences, then deformation stress is reduced, but high-frequency signal leakage occurs through the gap
Solution Approach 1:
A waveguide structure is introduced as an intermediary component between the coaxial connector (attached to housing) and the microstrip line (on substrate). The waveguide includes a first through-hole for the coaxial connector and a second through-hole for the microstrip line, with the second through-hole having dimensions to cut off transmission frequencies. This intermediary structure allows thermal expansion differences between housing and substrate while preventing signal leakage through the gap, as the waveguide's closed structure blocks electromagnetic radiation.
2Object-generated harmful factors
If the central conductor and microstrip line are directly connected in a closed space, then signal leakage is prevented, but stress concentration occurs at the connection point due to temperature change deformation
Solution Approach 1:
The connection path is segmented into separate sections: the coaxial connector connects to the first through-hole of the waveguide, and the microstrip line connects to the second through-hole of the waveguide. The central conductor has a projection that extends beyond the outer conductor and inserts through the first through-hole into the waveguide, while the microstrip line's strip line has a projection that inserts through the second through-hole. This segmentation allows each component to accommodate thermal expansion independently within the closed waveguide structure, preventing stress concentration while maintaining signal integrity.
3Object-generated harmful factors
If the second through-hole has dimensions to cut off transmission frequencies, then signal leakage is prevented, but the through-hole size is constrained
Solution Approach 1:
The second through-hole is designed with specific dimensional parameters that correspond to the cutoff frequency of the waveguide mode. By carefully selecting the hole diameter and length relative to the operating wavelength, the structure achieves signal leakage prevention at the desired frequency band. This parameter optimization allows the through-hole to function as both a mechanical connection path and an electromagnetic filter, balancing the constraints on hole size with the requirement for effective signal blocking.
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 eliminates high-frequency signal leakage and prevents stress at the connection, enhancing the reliability of the coaxial connector and microstrip line interface by maintaining a stress-free connection and ensuring reliable signal transmission.
Implementation Method 1
a waveguide having a first through hole, and a second through hole spaced apart from the first through hole and having such a dimension as to cut off a transmission frequency
Data Source
AI summary
A coaxial microstrip line conversion circuit includes: a waveguide including first and second through holes, spaced apart from each other, the second through hole having a dimension to cut off a used frequency; a coaxial connector including a central conductor including a projection projecting from an axial end of an outer conductor; and a microstrip line including a ground conductor provided on one surface of an insulating substrate, and a strip line provided on the other surface of the insulating substrate and including a projection projecting axially from the ground conductor. The outer conductor is connected to an outer wall of the waveguide. The projection of the central conductor is inserted through the first through hole into the waveguide, the ground conductor is connected to an inner wall of the second through hole, and the projection of the strip line is inserted through the second through hole into the waveguide.