Every literature I have found about magnetron explains the operations and electromagnetic field inside the cavity of a magnetron, but I am curious to know how/which direction the electric field will be directed through the antenna of a magnetron, when it is placed in free space. What will be the far field pattern? will it act like a monopole antenna?
A magnetron usually feeds into a waveguide which in turn feeds a horn antenna ( a tapered waveguide) which has a far field pattern in the form of a main beam with a number of side lobes. The horn could also be used as a feeder at the focus of a parabolic dish that produces a thinner beam. The polarization of the radiated field depends on the waveguide mode generated by the magnetron that could be either TE or TM.
Thank you Mr. Asfar for your answer. I am interested to heat a cylindrical object by passing a magnetron through the central axis of the cylinder. My choice is to send the magnetron without any waveguide, but with a pusher plate (holding the magnetron) and a reflector plate just opposit to it. This situation made me look for field pattern outside of a magnetron when powered up in open space. Can you refer me some literature/insight about this matter please. I would really appreciate your time. Thanks.
yes, I think the magnetrons are build to have a wave guide. Their exit port (this monopole antenna behind the ceramic finger) has to be matched by the waveguide impedance.. it will not emit very well in free space (my believing), or at least its lifetime will be shortened a lot. You may get the datasheets of the magnetron you have. they must have these polar plots of working conditions..
Myers et al. US005216327 Patent, coaxial adaptor for conventional magnetrons..
Somebody knows where to buy them?
Thank you Mr. Alberts and Mr. Asfar for your answers. I had a few doubts about this issue and your answer was helpful.
https://www.researchgate.net/post/Is_it_possible_to_find_a_magnetron_without_port_matching_condition#share
Sir, can you please elaborate on the propogation behaviour of the microwaves as they come out of the magnetron.I am curious to know that how microwaves traverse a right angled waveguide since it is having a reflecting surface.the hole of the antenna is exactly facing the flat waveguide surface of the oven.Moreover, what is the effect of shape of the opening in the magnetron antenna.Eg. if it's circular as against to it being triangular?
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