Common Circular Waveguide Sizes and Frequency Ranges
This reference chart lists common circular (round) waveguide sizes used in microwave systems, radar, satellite communications, rotary joints, feed horns, laboratory systems, and high-power RF applications.
Dimensions shown are approximate inside diameters of the circular waveguide. Frequency ranges are approximate dominant mode operating regions.
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Circular WG Inside Diameter Approx Frequency Range ------------------------------------------------------------------ WG-24 24.00" 0.35 - 0.55 GHz WG-18 18.00" 0.50 - 0.75 GHz WG-14 14.00" 0.65 - 1.00 GHz WG-10 10.00" 0.90 - 1.40 GHz WG-8 8.00" 1.10 - 1.80 GHz WG-6 6.00" 1.50 - 2.50 GHz WG-5 5.00" 1.80 - 3.00 GHz WG-4 4.00" 2.20 - 4.00 GHz WG-3 3.00" 3.00 - 5.80 GHz WG-2.5 2.50" 3.80 - 7.00 GHz WG-2 2.00" 5.00 - 9.00 GHz WG-1.75 1.75" 6.00 - 11.00 GHz WG-1.5 1.50" 7.00 - 13.00 GHz WG-1.25 1.25" 8.50 - 15.00 GHz WG-1 1.00" 10.00 - 18.00 GHz WG-0.75 0.75" 15.00 - 26.00 GHz WG-0.50 0.50" 22.00 - 40.00 GHz WG-0.375 0.375" 30.00 - 50.00 GHz WG-0.25 0.250" 45.00 - 75.00 GHz WG-0.188 0.188" 60.00 - 110.00 GHz WG-0.125 0.125" 90.00 - 140.00 GHz
Common Uses of Circular Waveguide
- Rotary joints for radar antennas and microwave systems
- Feed systems for satellite earth stations and feed horns
- High-power microwave transmission systems
- Low-loss millimeter wave laboratory systems
- Mode converters and specialized RF propagation systems
- Antenna feed assemblies and horn antennas
Important Technical Notes
- Circular waveguide does not use the standard WR numbering system used for rectangular waveguide.
- Frequency ranges shown are approximate dominant mode operating regions and may vary depending on the specific mode used.
- Circular waveguide commonly supports TE11 dominant mode operation.
- Larger circular waveguides may support multiple propagation modes simultaneously.
- Waveguide cutoff frequency is determined primarily by the inside diameter.
- Circular waveguide is often preferred in rotating systems because it maintains consistent electrical properties during rotation.
- Precision machining and alignment become increasingly important at microwave and millimeter-wave frequencies.
- Flexible circular waveguide sections are available for specialized applications.
General Diameter vs Frequency Relationship
Larger Diameter Circular WG Lower Frequency Operation Smaller Diameter Circular WG Higher Frequency Operation Example: ---------------------------------------------------------- 10 inch circular waveguide ~1 GHz region 1 inch circular waveguide ~10-18 GHz region 0.25 inch circular waveguide ~45-75 GHz region
W5SWL Electronics – Circular Waveguide Reference Guide