Snap-on Balun for RF Current Trapping on Coaxial Cables
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Solution Overview
Problem
Conventional baluns are difficult to install on coaxial cables after both ends are connectorized and soldered, and they are not suitable for high-field environments such as those found in high-energy physics experiments, where they can be affected by strong magnetic and electric fields.
Innovation Solution
A snap-on coaxial cable balun with adjustable reactive elements, including capacitance and inductance, that can be adjusted electrically or mechanically using non-magnetic mechanical-movement devices, allowing for installation from the side and operation in high-field environments without introducing extraneous capacitances or inductances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional baluns are used, then RF current trapping function is provided, but installation becomes difficult after cable ends are connectorized and soldered
Solution Approach 1:
The balun is divided into two separate halves that can be assembled around the cable from the side. This segmentation allows installation after the cable is already connectorized and soldered, eliminating the need to slide the entire balun over the cable end.
Solution Approach 2:
The two halves of the balun are designed to nest together around the cable, with one half enclosing the other. This nested structure allows the balun to be installed from the side rather than requiring end-access, solving the installation accessibility problem.
2Reliability
If conventional baluns are used in high-field environments, then RF current trapping is achieved, but the balun is affected by strong magnetic and electric fields
Solution Approach 1:
The balun uses non-magnetic materials and designs the magnetic path to be external to the cable shield, changing the physical parameters of the construction to eliminate susceptibility to strong magnetic and electric fields in high-field environments.
Solution Approach 2:
The balun introduces an external magnetic path that acts as an intermediary, directing magnetic flux away from the cable and preventing direct interaction between the strong external fields and the cable's electromagnetic signals.
3Adaptability or versatility
If adjustable reactive elements are added to the balun, then tuning capability is improved, but device complexity increases
Solution Approach 1:
The balun incorporates adjustable reactive elements that allow dynamic tuning of the trapping frequency. This dynamic adjustment capability enables the balun to be adapted to different operating conditions while maintaining a relatively simple overall structure.
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
Enables easy installation and adjustment of RF current trapping on coaxial cables in high-field environments, ensuring effective suppression of stray RF currents while maintaining stability within strong magnetic and electric fields.
Implementation Method 1
an LC circuit that is mounted to the case and that has a resonance frequency at a frequency of RF signals carried on the at least one inner conductor
Data Source
AI summary
Apparatus and method for a radially attachable RF trap attached from a side to a shielded RF cable. In some embodiments, the RF trap creates a high impedance on the outer shield of the RF cable at a frequency of RF signals carried on at least one inner conductor of the cable. In some embodiments, an RF-trap apparatus for blocking stray signals on a shielded RF cable that has a peripheral shield conductor and a inner conductor for carrying RF signals includes: a case; an LC circuit having a resonance frequency equal to RF signals carried on the inner conductor; projections that pierce and connect the LC circuit to the shield conductor; and an attachment device that holds the case to the cable with the LC circuit electrically connected to the shield conductor of the shielded RF cable.