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.
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.
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.