Hollow Waveguide Directional Coupler Spacing
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Solution Overview
Problem
Manufacturing hollow waveguide directional couplers for millimeter-wavelength ranges is challenging due to the need for a high number of coupling openings, which increases manufacturing effort and susceptibility to damage, especially when strong couplings are required.
Innovation Solution
Increasing the distance between coupling openings to an uneven multiple of λg/4 and allowing larger cross-section wall portions, enabling the use of conventional manufacturing methods while maintaining directivity and mechanical stability, and optionally using broad or narrow side-walls to simplify the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of coupling openings is increased to achieve strong coupling, then the coupling efficiency is improved, but the manufacturing effort and susceptibility to damage increase exponentially
Solution Approach 1:
The patent changes the spacing parameter between coupling openings from the conventional λg/4 to uneven multiples of λg/4 (such as 3λg/4, 5λg/4). This parameter change allows the use of fewer coupling openings while maintaining the required coupling efficiency, thereby reducing manufacturing effort and the exponential increase in damage susceptibility that would otherwise occur with a higher number of openings.
Solution Approach 2:
Instead of following the conventional approach of using λg/4 spacing between coupling openings, the patent inverts this convention by using uneven multiples of λg/4. This inversion allows achieving the same coupling effect with fewer openings, thus resolving the contradiction between coupling efficiency and manufacturing complexity.
2Length of moving object
If the distance between coupling openings is decreased to reduce coupler length, then the directivity is improved, but the wall portions become weaker and more susceptible to damage
Solution Approach 1:
The patent changes the spacing parameter from conventional λg/4 to uneven multiples such as 3λg/4. This parameter change increases the distance between coupling openings, which strengthens the wall portions and improves manufacturing yield, while the overall coupler length is controlled through optimized design of the coupling section and waveguide dimensions.
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 approach reduces the number of coupling openings needed, decreases manufacturing costs, and enhances the mechanical stability and yield of the directional coupler, allowing for efficient production with conventional methods while maintaining high coupling efficiency and bandwidth.
Implementation Method 1
the fields coupled at the two openings from the transit hollow waveguide section to the driven hollow waveguide section propagate in both directions in the driven hollow waveguide
Implementation Method 2
two hollow waveguide sections connected to each other by a plurality of coupling openings formed in a wall extending between the hollow waveguide sections
Implementation Method 3
the fields that propagate in the same direction as in the transit waveguide interfere constructively, whereas, in the opposite direction, they have a phase difference of λ/2 and thus cancel each other
Data Source
AI summary
A hollow waveguide directional coupler comprises two hollow waveguide sections that are coupled to each other by a plurality of coupling openings formed in a wall extending between the hollow waveguide sections. Two adjacent coupling openings have a distance of 3λg/4. from each other, λg being the wavelength of the nominal center frequency of the operating frequency range of the directional coupler.