Microwave Generator Parallel Spark Gaps Plasma Inductance
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Solution Overview
Problem
Conventional microwave generators are unable to generate broadband microwave pulses with high energy density above 600 MHz due to the physical properties of the switch plasma, limiting their frequency range and efficiency.
Innovation Solution
The solution involves connecting multiple spark gaps in parallel within the coaxial DS resonator geometry, which reduces the plasma inductance and shortens the pulse rise time, allowing for higher frequency components to be emitted by distributing the discharge current over multiple plasma channels, and optimizing the impedance matching to enhance energy radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spark gap is used in the DS resonator, then the structure is simple, but the frequency range is limited to below 600 MHz due to plasma inductance
Solution Approach 1:
The single spark gap is divided into multiple parallel spark gaps. Each spark gap has its own plasma channel, and when connected in parallel, their inductances combine reciprocally (1/L_total = 1/L1 + 1/L2 + ...), reducing the total plasma inductance. This enables the system to generate frequencies above 600 MHz while maintaining structural simplicity.
2Adaptability or versatility
If multiple spark gaps are connected in parallel, then the frequency range extends above 600 MHz, but the device complexity increases
Solution Approach 1:
Multiple spark gaps are merged in parallel within the same resonator structure, sharing common electrodes and housing. This configuration reduces the overall device complexity compared to using multiple separate resonators, while achieving the desired frequency extension through reduced plasma inductance.
3Speed
If the plasma inductance is reduced by using multiple parallel spark gaps, then the pulse rise time is shortened, but the manufacturing complexity increases
Solution Approach 1:
The electrode surfaces are equipped with multiple localized discharge points (protrusions or sharp edges) that serve as predetermined breakdown locations. This ensures uniform and simultaneous ignition across all parallel spark gaps, achieving consistent pulse rise time characteristics while simplifying manufacturing through standardized electrode designs.
4Power
If the distance between spark gap electrodes is reduced, then the breakdown voltage decreases and ignition is easier, but the plasma inductance increases
Solution Approach 1:
Instead of reducing the electrode distance in a single spark gap, the system segments the discharge into multiple parallel paths. Each spark gap maintains an optimal electrode distance for easy ignition, while the parallel configuration reduces total inductance, thereby achieving both easy breakdown and fast pulse rise time.
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
This approach increases the high-frequency components in the emitted pulse shape, extending the frequency range above 600 MHz and improving the efficiency and service life of the microwave generator by reducing plasma inductance and power losses.
Implementation Method 1
The breakdown of the spark gap can also be brought about in a targeted manner by a suitable trigger mechanism
Implementation Method 2
Together with the physical properties of the switch plasma in the spark gap and in connection with the electrical wiring
Implementation Method 3
this capacitance forms an oscillating circuit which consists of an ohmic resistance R, an inductance L and a capacitance C
Implementation Method 4
generate a broadband microwave pulse with the so-called DS technology (Damped Sinusoid = damped sinusoidal oscillation)
Implementation Method 5
connecting multiple spark gaps in parallel within the coaxial DS resonator geometry, which reduces the plasma inductance
Implementation Method 6
distributing the discharge current over multiple plasma channels
Implementation Method 7
The magnitude of the energy radiated into the environment is largely determined by the impedance matching of the oscillating circuit to the environment
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The microwave generator has a resonator having two mutually spaced resonator electrodes (12,14) forming a spark gap device configured to break down upon being subjected to a firing voltage applied between the resonator electrodes. The spark gap device is formed with multiple spark gaps (SG) connected in parallel with each other. The resonator electrodes are disposed with a defined spacing reduced at spark gaps to identical smaller spacing.