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Name: Louis
Status: Other
Grade: Other
Location: CA
Country: United States
Date: June 2008
Question:
Why in a medical linear accelerator the cross-section of a waveguide used to transmit microwave power is rectangular in shape whereas those of an accelerating waveguide used to accelerate the electrons is circular?


Replies:
Hi Louis,

The difference between a circular and a rectangular waveguide is polarization. A circular waveguide will pass (or conduct) a high frequency power of any polarization, whereas a rectangular waveguide can only pass a signal of one specific polarization.

Not being an expert in either of the specific uses you quote, I cannot tell you why polarization is important in one of the applications you mention, but not important to the other.

Regards,

Bob Wilson

The shape of the waveguide affects the shape of the electromagnetic field produced. Different applications require different field shapes for best results.

Scott Smith


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