WR-137 Waveguide
The WR137 waveguide is a rectangular waveguide commonly used in the C-band frequency range, particularly for radar, satellite communications, and radio astronomy work just below the hydrogen line.
Here are its key specifications:
| Parameter | Value |
|---|---|
| Designation | WR137 |
| Frequency range (typical) | 5.85 GHz – 8.20 GHz |
| Recommended band center | 7 GHz (approx.) |
| Internal dimensions (a × b) | 1.372 in × 0.622 in (34.85 mm × 15.80 mm) |
| Cutoff frequency (TE₁₀ mode) | ~4.26 GHz |
| Flange types | CPR137F, UG-1730/U, and variants |
| Material | Commonly aluminum, brass, or copper |
Technical Notes
- TE₁₀ is the dominant mode in WR137, so the long side of the waveguide should be oriented horizontally (E-field along the short wall).
- The cutoff frequency determines the lowest usable frequency — below this, the waveguide will not propagate.
- Because WR137 is too small for 1.42 GHz, it isn’t suitable for hydrogen line radio astronomy. For that, waveguides like WR650 waveguide (cutoff ~900 MHz) are typically used.
Common Applications
- C-band satellite uplink/downlink
- High-power microwave systems
- Radar front-end feed waveguides
- Lab test waveguide sections and components (bends, twists, transitions)