Ultrabroad Orthogonal-Mode Junction Coupler Design
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Solution Overview
Problem
Conventional orthogonal mode junction couplers are bulky and suffer from poor insulation between input ports, leading to degradation of modal purity due to higher order mode excitation, especially in ultra-wideband applications.
Innovation Solution
A compact ultra-wideband orthogonal mode junction coupler with a central conductor having a cross-sectional shape and four supply lines connected to branches via ohmic contacts, ensuring electrical insulation and controlled phase distribution for stable bi-polarized operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional orthogonal mode junction couplers are used, then dual-polarization signal separation is achieved, but the device becomes bulky and input port insulation deteriorates
Solution Approach 1:
The central conductor is nested within the outer conductor cavity, with the cross-shaped central conductor positioned inside the circular outer conductor. This nested configuration allows the coupler to maintain effective insulation between input ports while minimizing the overall device volume, directly resolving the contradiction between reliability and size.
Solution Approach 2:
The invention transitions from a conventional planar or linear arrangement to a three-dimensional nested structure where the cross-shaped central conductor occupies the interior space of the circular outer conductor. This dimensional optimization enables compact packaging while preserving the necessary electrical isolation between ports.
2Reliability
If conventional orthogonal mode junction couplers are used, then signal separation is achieved, but modal purity degrades due to higher order mode excitation
Solution Approach 1:
The central conductor is designed with a cross-shaped asymmetric geometry featuring four arms of equal length extending from the center. This specific asymmetric configuration is optimized to excite only the desired orthogonal modes while suppressing higher order modes, thereby maintaining modal purity without requiring additional compensating structures.
Solution Approach 2:
The four arms of the cross-shaped central conductor are positioned at specific locations within the outer conductor cavity, creating localized field distributions that selectively excite only the fundamental orthogonal modes. This local geometric optimization ensures modal purity while keeping the overall structure simple.
3Reliability
If supply lines are connected to central conductor at different planes, then manufacturing is easier, but coupling between input ports increases
Solution Approach 1:
All four supply lines are connected to the central conductor at the same transverse plane, creating an equipotential connection interface. This configuration ensures symmetric current distribution and minimizes coupling between input ports, while the common-plane connection simplifies manufacturing by establishing a single reference plane for all connections.
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 provides stable ultra-wideband mono-mode and bi-polarized excitation with low coupling between input ports, eliminating the need for external compensation circuits and achieving compact design.
Implementation Method 1
orthogonal mode junction coupler for separating bands with double polarization
Implementation Method 2
a branching device which subdivides a waveguide carrying the two orthogonal polarizations into two arms of rectangular waveguides
Implementation Method 3
Two opposite branches of the central conductor are supplied with radio frequency signals by respectively two opposite supply lines to trigger a determined polarization
Implementation Method 4
an outer conductor comprising a cavity in which extends a central conductor
Implementation Method 5
each supply line is connected to a branch of the central conductor by an ohmic contact
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to an orthogonal-mode junction coupler with an ultrabroad bandwidth or a wavelength waveguide noteworthy in that it includes what is called an external conductor (8) comprising a cavity (9) in which a central conductor (10) extends, said central conductor being electrically isolated at radiofrequencies with the external conductor (8), said central conductor (10) being supplied by supply lines (15, 16, 17, 18) passing through the external conductor (8) and emerging in the cavity (9) of said external conductor (8).