A note on the cutoff frequency of TE/sub 01/ mode in TEM cells

It is shown that due to the similarity of the structures of the TEM cell and the finned waveguide, the closed-form expression for the cutoff frequency of the TE/sub 10/ mode in the finned waveguides can be used to calculate the cutoff frequency of the TE/sub 01/ mode in the symmetric TEM cells. The results obtained by the expression given agree with various numerical methods to within 1%. The results calculated by this expression are compared with those obtained by an approximate analytical expression.<
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