Miter Bends & Polarizers - Mode Conversion Losses

Mode conversion losses from HE11 in a miter bend with a flat mirror can be estimated from the diameter (D) and the wavelength (lambda) using the formula:

    mode conversion loss per miter bend ~ 2.4 (lambda/D)3/2 dB
This formula represents an average over a range of frequencies. The actual loss can be expected to be somewhat above or below this estimate. Some comparisons of measured and calculated losses on waveguide runs with 2 - 8 miter bends:

waveguide
diameter
frequency
miter bends
tested
experimental loss
per miter bend
calculated loss
per miter bend
31.75 mm
110 GHz
6
0.06 dB
0.06 dB
63.5 mm
60 GHz
8
0.03 dB
0.05 dB
31.75 mm
56 - 64 GHz
2
0.15 dB
0.15 dB