Nonlinear Transmission Line for High-Voltage Pulse Sharpening
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Solution Overview
Problem
Producing high voltage pulses with fast rise times is challenging, especially in compact form, and existing technologies are limited to low voltage applications, making it difficult to achieve steep rise times for high voltage pulses with variable widths and high repetition rates.
Innovation Solution
A high voltage nonlinear transmission line comprising a series of circuit elements with resistors, nonlinear semiconductor junction capacitance devices, and inductors, which sharpens the rise time of input pulses by varying capacitance with voltage, allowing for faster output rise times while maintaining similar voltage and pulse width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard electrical components are used to generate high voltage pulses, then the system is simple and reliable, but the rise time cannot be made fast enough (less than 50 ns)
Solution Approach 1:
The transmission line is divided into multiple discrete cells, each containing a varactor diode and inductor. This segmentation allows the nonlinear capacitance effect to be distributed throughout the line, enabling fast rise times through the cumulative sharpening effect of multiple cells while maintaining a manageable system structure.
Solution Approach 2:
The patent employs varactor diodes whose capacitance dynamically changes with applied voltage. During the leading edge of the pulse, the capacitance is lower, allowing faster voltage changes. As the pulse progresses and voltage increases, the capacitance increases, naturally limiting the rise time and providing waveform shaping without complex control circuits.
2Speed
If nonlinear transmission lines with varactor cells are used, then fast rise times can be achieved, but the system is limited to low voltage applications (less than 15V)
Solution Approach 1:
The patent combines multiple varactor cells in series within each circuit element, allowing the voltage handling capability to be increased by distributing the total voltage across multiple devices. This merging approach enables the transmission line to handle high voltages (greater than 10 kV) while each individual varactor operates within its safe voltage range, thus achieving both fast rise times and high voltage capability.
Solution Approach 2:
The transmission line uses a composite structure combining varactor diodes, inductors, and resistors in specific configurations. This composite circuit element leverages the nonlinear capacitance of varactors, the energy storage of inductors, and the damping of resistors to create a system that simultaneously achieves fast rise times and high voltage tolerance.
3Manufacturing precision
If steep pulse rise is achieved for high voltage pulses, then the pulse quality is improved, but it becomes difficult to produce variable pulse widths and high repetition rates
Solution Approach 1:
The patent achieves variable pulse widths by changing the input pulse parameters (width, amplitude) without requiring changes to the transmission line structure. The nonlinear transmission line responds adaptively to different input conditions, maintaining fast rise times across a range of pulse widths. The varactor capacitance changes with voltage, automatically adjusting the waveform shaping for different input amplitudes and widths.
Solution Approach 2:
The nonlinear transmission line serves multiple functions: it sharpens rise times, handles high voltages, supports variable pulse widths, and accommodates high repetition rates. The same basic cell structure (varactor + inductor + resistor) provides all these functions simultaneously, making the system versatile without requiring additional components or complex control mechanisms.
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 nonlinear transmission line effectively reduces the rise time of high voltage pulses, achieving faster output pulses with the same voltage and repetition rate as input pulses, suitable for high voltage applications up to 100 kV and pulse repetition frequencies of 10 kHz to 100 kHz.
Implementation Method 1
each of the plurality of circuit elements includes a resistor and a nonlinear semiconductor junction capacitance device
Implementation Method 2
each of the nonlinear semiconductor junction capacitance devices have a capacitance that changes nonlinearly with voltage
Data Source
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AI summary
Some embodiments include a high voltage nonlinear transmission line that includes a high voltage input configured to receive electrical pulses having a first peak voltage that is greater than 5 kV having a first rise time; a plurality of circuit elements electrically coupled with ground, each of the plurality of circuit elements includes a resistor and a nonlinear semiconductor junction capacitance device; a plurality of inductors, at least one of the plurality of inductors is electrically coupled between two circuit elements of the plurality of circuit elements; and a high voltage output providing a second peak voltage with a second rise time that is faster than the first rise time.