Yes. In my microwave class (2002) we installed capacative and inductive
loads into a waveguide by inserting a thin plate with a small rectangular
hole in the center in between two of the waveguide sections. The circuit was
tuned using a simple rotary micrometer. A screw device with 1/1000 "
graduations marked on the side that drove a tuning pin into a lobe of the
microwave E-Field. We made some before and after measurements and then
calculated the resulting impedance of the load using a Smith chart.
2450 MHz @ 1 Kw. These are scrapped parts from an old Sanyo microwave oven I
found at the Salvation Army surplus store.
This should be enough power to get some plasma generation, but I don't know
yet that it will be sufficient for real material processing. I will probably
need to upgrade to higher power components later on, but I am hoping that
this 1Kw power level will be good enough to do some small sample runs and
get some working data.
The problem I am having right now is finding high power waveguide equipment
at a price that I can afford. It looks like I am going to have to fabricate
my own dummy load and circulator as well before it is all done.
Sounds like an interesting project
have been involved in similar type of thing using a circular cavity -
pulling a glass fibre 'rope' through it that had been dipped in a curing
agent - continuous curing of a fibreglass rebar for concrete-
Be intersted toknow a little more about the criteria for developing a plasma
in the system - is there a gas emplyed -apart from air-
I am just learning about these techniques now myself, so am probably not the
best person to ask.
These documents are several years old now, but maybe they can help point you
in the right direction.
Some IEEE Documents I found interesting that you can get from IEEE XPlore if
you are a member, or if your library has an IEEE account.
Ahmed I. Al-Shamma'a, Stephen R. Wylie, Jim Lucas, and Jiu Dun
Yan,"Atmospheric Microwave Plasma Jet for Material Processing", IEEE
TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 5, OCTOBER 2002 Page: 1863
Abstract-We have designed a low-cost and reliable 2.45-GHz waveguide-based
applicator to generate a microwave plasma jet (MPJ) at atmospheric pressure.
The MPJ system consists of a 1-6 kW magnetron power supply, a circulator, a
water-cooled matched load and the applicator. The applicator includes a
tuning section, which is required to reduce the reflected power and the
nozzle section. The plasma is formed by the interaction of the high
electrical field, generated by the microwave power, between the waveguide
aperture and the gas nozzle. A variety of gasses have been used to produce
the plasma including argon, helium, and nitrogen. A 2-kW 2.45-GHz MPJ
constructed using a rectangular waveguide WG9A (WR340) has been
investigated. An MPJ has been used for material processing applications
including cutting, welding, glass vitrification, and quartz/ceramic
processing. This paper discusses the design parameters and the potential of
the MPJ for industrial applications and how the jet can be tailored to suit
different tasks, by adjusting the various parameters such as the type of
gas, the flow rate, the input power, and the nozzle design. Index
Terms-Electrical field simulation, industrial applications, material
processing, microwave plasma, waveguide.
Paul P. Woskov, Senior Member, IEEE and Kamal Hadidi, Member, IEEE, "Large
Electrodeless Plasmas at Atmospheric Pressure Sustained by a Microwave
Waveguide", IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 30, NO. 1, FEBRUARY
2002 Page: 156
Abstract-A 1.5-kW 2.45-GHz magnetron source has been used to reliably
sustain large electrodless plasmas at atmospheric pressure in a shorted
waveguide without a resonator. Working gases have been air, nitrogen, and
heated off gases of sulfur containing ores and coal in nitrogen. Various
colorful plasmas of value to environmental monitoring and processing
applications are generated depending on the composition of the working gas.
Index Terms-Atmospheric pressure, electrodes, microwave, plasma.
dont know if your familiar with the work done by
either AC Metaxas or/and R Meredith
Industrial Microwave Heating (by both authors)
this is an IEE publication - and is my microwave hands on bible and there is
some good stuff on plasma
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