31.75 mm vacuum miter bend with polarizing mirror. Water-cooled cover also shown. |
88.9 mm vacuum miter bend with water-cooled remote-controlled polarizing mirror. |
63.5 mm non-vacuum miter bend with remote-controlled polarizing mirror. |
waveguide
diameter |
frequency |
measured loss
per miter bend |
| 31.75 mm |
110 GHz |
0.06 dB |
| 63.5 mm |
60 GHz |
0.03 dB |
| 31.75 mm |
56 - 64 GHz |
0.15 dB |
Non-vacuum miter bends are made with corrugated waveguides inserted into a block. The ends of these waveguide inserts are cut at 45 degrees by wire electron discharge machining (EDM) to prevent damage to the corrugations. The mirror is bolted into the block.
Vacuum miter bends have corrugated waveguides machined in one piece with the miter block. Aside from the seals needed to connect ordinary waveguides to the ends, the only vacuum seal required is a Helicoflex® metal seal under the mirror.
Extremely low loss miter bends utilizing internal mode converters have also been developed by General Atomics. For example, HE11 miter bends of this type in 31.75 mm waveguide have only 0.02 dB loss per bend at 110 GHz. Low-loss miter bends for the TE01 mode have also been made with this technique.
Polarizing miter bends using grooved polarizing mirrors are available with all miter bend types. Remotely-controlled miter bend polarizers are available for high power vacuum and non-vacuum applications.