Waveguide Rotary Joint with Half-Height Sections
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Solution Overview
Problem
Existing waveguide rotary joints for mobile satellite communications are either large and expensive or have high loss and limited power-handling capabilities, making them unsuitable for low-profile applications in aeronautical and ground mobile systems.
Innovation Solution
A compact waveguide rotary joint design that combines features of coaxial and circular waveguide joints, utilizing half-height waveguides and a non-contacting center pin with a choke cavity, allowing for broader bandwidth and reduced height, enabling 360° rotation without mechanical hard stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a circular waveguide rotary joint is used, then power-handling capability is improved, but profile height increases significantly
Solution Approach 1:
The circular waveguide is segmented into two half-height waveguide portions that are positioned side-by-side rather than stacked vertically. This segmentation allows the waveguide to maintain its full power-handling cross-sectional area while reducing the vertical profile height, as each half-height portion contributes to the overall effective area without requiring double the vertical space.
Solution Approach 2:
The invention transitions from a vertical stacking arrangement to a horizontal side-by-side arrangement of waveguide portions. By utilizing the horizontal dimension more effectively and reducing reliance on vertical space, the design achieves the same power-handling capability with reduced profile height, effectively redistributing the spatial requirements from the vertical to the horizontal plane.
2Length of stationary object
If a coaxial rotary joint is used, then profile height is reduced, but power-handling capability decreases
Solution Approach 1:
The invention merges the advantages of both coaxial and circular waveguide designs by combining a low-profile coaxial rotary joint mechanism with half-height waveguide portions that provide enhanced power-handling capability. The coaxial center pin structure maintains the low profile while the expanded half-height waveguide portions increase the effective cross-sectional area for power transmission, creating a hybrid structure that achieves both goals simultaneously.
3Reliability
If TM01 mode suppressing chokes are added to circular waveguide rotary joints, then mode purity is improved, but profile height increases
Solution Approach 1:
The invention extracts and eliminates the TM01 mode suppressing chokes from the circular waveguide rotary joint design. By using half-height waveguide portions instead of full-height circular waveguides, the design inherently suppresses unwanted modes without requiring additional choke structures, thereby removing the source of excessive profile height while maintaining mode purity through the geometric constraints of the half-height configuration.
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 a significantly lower profile, reduced insertion loss, and improved power-handling capabilities, making it suitable for low-profile applications while maintaining consistent performance over all rotations.
Implementation Method 1
the first end is arranged in and RF coupled to the first waveguide portion, the second end is arranged in and RF coupled to the second waveguide portion
Implementation Method 2
a choke cavity arranged between the first waveguide portion and the second waveguide portion
Data Source
AI summary
A waveguide rotary joint includes a first waveguide portion for receiving a microwave signal, a second waveguide portion for outputting the received microwave signal, and a conductive pin including a first end and a second end distal from the first end, the first end arranged in and RF coupled to the first waveguide, and the second end arranged in and RF coupled to the second waveguide, and a choke cavity is arranged between the first waveguide portion and the second waveguide portion. The first waveguide and the second waveguide are rotatable relative to each other about a longitudinal axis of the conductive pin.