Mi-Wave · Circular Waveguide
370 Series Circular Waveguide
Low-loss flanged circular waveguide sections covering 12.6 GHz to 320 GHz
The Mi-Wave 370 Series is flanged circular waveguide: a hollow copper tube with a standard flange at each end for low-loss transmission from 12.6 GHz to 320 GHz. Unlike rectangular guide it carries both the TE11 dominant mode and the TE01 low-loss mode, so a system designer can pick ordinary transmission or a very low-loss, high-power path. Satellite feeds, radar, mm-wave test benches and aerospace research are the usual homes for it. Evencat is an authorized Mi-Wave distributor in Taiwan and quotes every band and ID.
Overview
The 370 Series lists 14 band models from X-band at 8 GHz to J-band at 220 GHz, each with a choice of inside diameters that set the cutoff frequency for the band. Standard male and female flanges (UG-39/U, UG-385, UG-387/U-M and so on) let a section drop into an existing waveguide run; where no flange is wanted, the 371 Series is the same tube without flanges for custom integration. High-conductivity copper keeps conductor loss to a minimum, and tight machining tolerances give repeatable electrical behavior even at the top of the range. Because a circular guide has no center conductor, its loss at mm-wave frequencies is well below that of coaxial line. Mi-Wave will also design to a non-standard band, mode or mechanical envelope. When you specify a section, check the ID against the modes you intend to carry and the flange against the hardware on either side; we can supply the outline drawing before you order.
Key specifications
| Frequency range | 12.6 GHz – 320 GHz (by model) |
|---|---|
| Propagation modes | TE11 (dominant), TE01 (low-loss, high-power) |
| Conductor material | High-conductivity copper |
| Flange types | UG-39/U, UG-419/U, UG-595/U, UG-599/U, UG-383/U, UG-383, UG-385, UG-387/U, UG-387/U-M |
| Inside diameter range | 0.049" – 1.094" (by band model) |
| X-band model (370X-.XXX/39) | 8–12.4 GHz; ID 1.094", .938", .797"; flange UG-39/U |
| V-band model (370V-.XXX/385) | 50–75 GHz; ID .165", .141", .125"; flange UG-385 |
| W-band model (370W-.XXX/387) | 75–110 GHz; ID .125", .110", .094", .082"; flange UG-387/U-M |
| D-band model (370D-.XXX/387) | 110–170 GHz; ID .082", .075", .067", .059"; flange UG-387/U-M |
| J-band model (370J-.049/387) | 140–220 GHz; ID .049"; flange UG-387/U-M |
| TE11 cutoff frequency | fc = (1.841 × c) / (π × D) |
| TE01 cutoff frequency | fc = (3.832 × c) / (π × D) |
Features
Very wide band coverage
The 370 Series runs from 12.6 GHz to 320 GHz, X-band through J-band, so one family covers most microwave and mm-wave transmission needs.
Low VSWR transmission
Controlled bore and flange geometry keep the VSWR low, which limits reflection and protects signal integrity in demanding high-frequency links.
Two propagation modes
Sections support the TE11 dominant mode for ordinary transmission and the TE01 low-loss mode for high-power or long runs, so the designer chooses the mode that suits the system.
Precision machining
Each section is held to tight dimensional tolerances, so the electromagnetic behavior is consistent from unit to unit at mm-wave frequencies.
Flanged or plain tube
The 370 Series carries standard flanges from UG-39/U to UG-387/U-M for direct mating; the 371 Series omits the flanges for embedded or custom assemblies.
Custom designs
Mi-Wave designs circular guide for non-standard bands, special IDs and specific mode requirements when a catalog section does not fit.
Typical applications
Satellite communications
Ground-station and payload feed links
In Ku and Ka band earth stations and LEO payloads, 370 Series guide carries high power in the TE11 mode straight into the feed horn through its flange. Insertion loss is far below coaxial cable, which protects link margin, and the guide withstands the peak power a satellite transmitter demands without breakdown.
Radar and defense
Signal transport in mm-wave radar
W-band (75–110 GHz) automotive and defense phased-array radars use the TE01 low-loss version and the rotational symmetry of the bore to carry circular or dual-polarized signals. Tight control of bore concentricity in the 370 Series holds mode conversion over long runs to an acceptable level, so beam accuracy is preserved.
Measurement and calibration
Antenna ranges and component characterization
On a free-space antenna range or near-field scanner, a 370 Series section forms the transmission path between the standard-gain horn and the device under test. Its stable propagation and low VSWR avoid the reflection-induced uncertainty that appears above 30 GHz, giving repeatable, traceable S-parameter and pattern data.
Options and configuration
Tick the band, inside diameter and flange you need; the selections are collected into a list and carried into the quote form.
Band and model
Flange and series
Transmission mode
Downloads
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