Waveguide Rotary Joint for High-Bandwidth Microwave Data Transfer
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Solution Overview
Problem
Existing rotary joints for CT scanners face limitations in data rate due to the small relative bandwidth of waveguides and the inefficiency of small, narrow transmission antennas.
Innovation Solution
A rotary joint with a circular channel comprising an inner and outer ring, where the rings are rotatable relative to each other, and the channel includes sidewalls that can be reflective or absorptive to improve signal decoupling and transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional waveguide with a narrow radial slot is used, then the waveguide structure is maintained, but the bandwidth is limited and the data rate is restricted
Solution Approach 1:
The waveguide structure is segmented into multiple independent channels, each capable of carrying signals. By dividing the single waveguide into multiple parallel channels, the system can transmit multiple signals simultaneously, thereby increasing the overall data rate and effective bandwidth without requiring a larger physical structure.
Solution Approach 2:
The invention transitions from a two-dimensional cross-sectional view of a single waveguide to a three-dimensional multi-channel configuration. By utilizing the longitudinal dimension and creating multiple parallel signal paths within the waveguide structure, the system expands the available transmission capacity and bandwidth.
2Productivity
If a small pin antenna is used in the narrow radial slot, then the antenna fits the slot constraints, but the antenna bandwidth and efficiency are limited
Solution Approach 1:
The single pin antenna is segmented into multiple antenna elements arranged in arrays along the radial slot. These antenna arrays can be independently controlled and configured, allowing each element to contribute to the overall transmission. This segmentation enables beamforming and spatial diversity, significantly improving both bandwidth and transmission efficiency.
Solution Approach 2:
Multiple antenna elements are merged into a coordinated array system that works together to transmit and receive signals. By combining the capabilities of multiple small antennas into a unified array with phased control, the system achieves the performance of a larger, more efficient antenna while still fitting within the narrow slot constraints.
3Productivity
If the radial slot is made wider to accommodate better antennas, then antenna efficiency improves, but the waveguide structure is degraded
Solution Approach 1:
Instead of uniformly widening the radial slot, the invention applies local optimizations at specific positions where antenna elements are placed. The slot width is increased only locally at antenna mounting points to accommodate efficient antenna elements, while the rest of the waveguide structure maintains its original dimensions and structural integrity.
Solution Approach 2:
The system dynamically adjusts the electrical characteristics of the antenna array to compensate for the narrow slot constraints. Through phased array beamforming and adaptive signal processing, the system achieves high transmission efficiency without requiring physical modifications that would compromise waveguide integrity.
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 enables high-speed data transmission with improved bandwidth and efficiency by allowing for multiple reflections and adjustable antenna directivity, effectively overcoming the limitations of traditional waveguide-based systems.
Implementation Method 1
The inner antenna and the outer antenna are directed into a space between the inner ring and the outer ring. This allows to transfer microwave signals between the inner antenna and the outer antenna, if one of the antennas radiates signals into the channel and the other antenna receives signals from the channel.
Implementation Method 2
The channel and specifically the inner ring and the outer ring may reflect microwave signals, such that the microwave signals propagate through the ring.
Implementation Method 3
The sidewalls are not necessary for the transmission function of the channel but can help to decouple the signal transmitted from the environment or neighboring channels by using reflective or absorptive sidewalls.
Data Source
Figure 1~2
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Figure 5~6
AI summary
A coupler provides a high speed datalink between rotating parts comprising a circular channel enclosing a hollow-cylindric volume and at least two antennas. The circular channel is of electrically conductive material and includes an inner ring, an outer ring rotatable against the inner ring, and two sidewalls on both sides of the rings. An inner antenna is mechanically coupled to the inner ring and an outer antenna is mechanically coupled to the outer ring. The antennas are configured for a microwave signal connection between them based on multiple reflections at the rings.