Coaxial Cable Loop Balun for Magnetic Field Environments
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Solution Overview
Problem
Existing baluns face challenges in low frequency ranges due to size limitations and are not suitable for magnetic field environments, as ferrite materials cause magnetic saturation, and previous designs have limitations in power capacity and size requirements for nuclear magnetic resonance devices.
Innovation Solution
A balun comprising at least two coaxial cables wound into loops, with specific connections and impedance configurations, allowing for phase difference management and reduced size, enabling use in magnetic fields without magnetic materials and enhancing power capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ferrite material is used to realize the balun, then the balun can be implemented at UHF, VHF and lower wave bands, but the balun cannot be used in a magnetic field environment due to magnetic saturation
Solution Approach 1:
The patent removes ferrite material from the balun structure, extracting the magnetic component that causes saturation in magnetic fields. The invention achieves balun functionality using only conductive elements (copper wires, PCB traces) and insulating materials, eliminating the harmful magnetic interaction while maintaining electrical performance across UHF, VHF and lower frequencies.
Solution Approach 2:
The patent replaces expensive ferrite materials with simple, inexpensive conductive elements such as copper wires and PCB traces. This substitution uses readily available materials that do not suffer from magnetic saturation, providing a cost-effective and environmentally robust solution that maintains functionality without requiring specialized magnetic materials.
2Ease of manufacture
If a 1/4 wavelength transmission line is used to implement the balun, then the implementation is simple, but the size becomes unacceptably large at UHF, VHF and lower wave bands
Solution Approach 1:
The patent transitions from a linear transmission line structure (one-dimensional) to a planar or compact three-dimensional configuration. By using parallel conductors, coplanar waveguides, or integrated PCB traces arranged in specific geometric patterns, the invention achieves the required electrical length and impedance transformation in a reduced spatial footprint, making the balun suitable for compact devices while maintaining manufacturing simplicity.
3Adaptability or versatility
If micro strips and strip lines are used to convert waveguide energy, then the conversion can be achieved, but the size grows when used at a low frequency range
Solution Approach 1:
The patent modifies the geometric parameters of the conductive structures (width, spacing, length, configuration) to achieve impedance matching and phase transformation at low frequencies without requiring proportionally large dimensions. By optimizing conductor width, spacing between parallel lines, and trace patterns on PCBs, the invention achieves effective signal conversion at UHF, VHF and lower frequencies while maintaining a compact size suitable for modern applications.
Data Source
AI summary
Embodiments of the present invention relate to the technical field of RF circuits, and in particular, to a balun. In an embodiment of the present invention, a balun is provided which comprises at least two coaxial cables, each of which is wound into at least one loop, and the inner and outer conductors of one end of all coaxial cables are connected respectively to each other and the inner and outer conductors of the other end are also connected to each other. The novel balun according to the embodiments of the present invention has a small size but a large power capacity and low cost, and can be used in a magnetic field environment.