Overview

The 580, 581, 582 and 585 Series all share the same construction: a short length of waveguide with an integral matched load, where the resistive dielectric is ground to a precise wedge so incoming energy is converted to heat gradually and reflection stays small over the whole band. The 580 Series is the low-power load for terminating measurement ports and runs up to 500 GHz. The 581 Series handles up to 10 W CW, and the 582 Series up to 75 W CW in Ka-band, which suits the output of a power amplifier. The 585 Series is a sliding matched load with a micrometer drive, used to move the load phase while measuring the VSWR of a device or the directivity of a coupler. All four use MIL waveguide flanges, and sub-THz or custom bands are available on request. When choosing, match the series to the power you must dissipate, then check the flange: Ka-band loads use UG-381/U on the 580, 582 and 585 Series but UG-599/U on the 581.

Key specifications

Series	580 (low power) / 581 (medium power) / 582 (high power) / 585 (sliding, adjustable)
Frequency coverage	8.2 GHz – 500 GHz (by series and band model)
VSWR (typical)	1.05:1 to 1.20:1 (by band and power class)
CW power rating	580 Series: 0.02 W – 6 W; 581 Series: 0.2 W – 10 W; 582 Series: 0.25 W – 75 W
Interface	Standard rectangular waveguide flanges (WR-2.2 to WR-90), to MIL sheets such as UG-381/U, UG-383/U, UG-385/U, UG-387/U and UG-595/U
Representative models (low power)	580K/595 (18–26.5 GHz), 580W/387 (75–110 GHz), 580J/387 (220–325 GHz), 580(2.2)/387 (325–500 GHz)
Representative models (medium power)	581X/UG39 (8.2–12.4 GHz, 10 W), 581W/387 (75–110 GHz, 1.2 W), 581H/387 (170–260 GHz, 0.2 W)
Representative models (high power)	582A/599 (26.5–40 GHz, 75 W), 582W/387 (75–110 GHz, 10 W), 582J/387 (220–325 GHz, 0.25 W)
Representative models (sliding)	585K/595 (18–26.5 GHz) through 585G/387 (140–220 GHz), VSWR ≤ 1.10:1
Load construction	Resistive dielectric machined to a tapered wedge
Uses	Instrument port termination, VSWR measurement reference, coupler calibration, power-amplifier output load

Features

8.2 GHz to 500 GHz

One product family spans K, Ka, Q, U, V, E, W, F, D, G, H and J bands and beyond, which covers satellite, 5G mm-wave and defense radar work.

Very low VSWR

The tapered resistive wedge gives the low-power 580 Series a VSWR down to 1.05:1, so the reflection coefficient at the terminated port barely disturbs the measurement.

Three power classes

The 580 Series absorbs up to 6 W CW, the 581 Series up to 10 W CW and the 582 Series up to 75 W CW in Ka-band, from bench test through system integration.

585 Series sliding load

A micrometer drive moves the load so an engineer can find the minimum and maximum VSWR of a DUT, which is the standard way to check coupler directivity and residual reflection.

MIL waveguide flanges

Every model carries a military-standard rectangular flange (UG-381/U through UG-595/U) and mates directly with existing test hardware.

Sub-THz and custom bands

Beyond the catalog, Mi-Wave designs sub-THz and special-band loads; ask us if your application falls outside the standard ranges.

Typical applications

VNA calibration

The load standard in VNA calibration

For S-parameter work between 8 GHz and 500 GHz, a matched termination is the L in an SOLT or TRL calibration: a known impedance that lets the analyzer move its reference plane to the DUT port and remove cable and connector error, so insertion loss and reflection are measured accurately.

Multi-port isolation

Terminating unused ports on multi-port devices

When a power divider, directional coupler or hybrid is measured, any port left open produces multiple reflections that corrupt the result. A matched load with VSWR below 1.05 absorbs the residual power, so each port sees a true match and isolation and directivity figures can be trusted.

Matched termination on the unused ports of multi-port waveguide components

Matched termination as a dummy load for transmitter and amplifier testing

System test

Dummy loads for transmitters and amplifiers

Before the antenna is fitted, or during burn-in, an earth-station transmitter, radar or mm-wave power amplifier needs a dummy load that turns the output into heat instead of radiating it. A high-power termination protects the front end from reflected power and keeps the test within radio regulations.

Options and configuration

Choose the series, band and flange your system needs; the selections are collected into a list and carried into the quote form.

Series (power class)

580 Series (low power)Low-power matched load, 18 GHz–500 GHz (X-band and WR-75 models also listed), VSWR down to 1.05:1, CW power up to 6 W by band 581 Series (medium power)Medium-power matched load, 8.2 GHz–260 GHz, CW power up to 10 W (X-Band), VSWR down to 1.10:1 582 Series (high power)High-power matched load, 12.4 GHz–325 GHz, CW power up to 75 W (Ka-Band); higher ratings up to 250 W CW on request 585 Series (sliding matched load)Micrometer-driven sliding load for VSWR measurement, coupler directivity and residual VSWR checks, 18 GHz–220 GHz

Flange

UG-339/UWR-90 flange on the 581X medium-power load, X-Band (8.2–12.4 GHz) UG-595/UWR-42 / WR-34 standard flange, K-Band and WR-34 (18–33 GHz) UG-381/UWR-28 standard flange, Ka-Band (26.5–40 GHz), on the 580, 582 and 585 Series UG-599/UWR-28 alternative flange, Ka-Band (26.5–40 GHz), on the 581 Series UG-383/UWR-22 / WR-19 standard flange, Q-Band and U-Band (33–60 GHz) UG-385/UWR-15 standard flange, V-Band (50–75 GHz) UG-387/UWR-12 to WR-3 standard flange, E/W/F/G/H/J-Band (60–325 GHz) UG-387/U-M (modified)Modified WR-6 flange for D-Band (110–170 GHz), where precise alignment is needed

0 options selected Standard configuration only

Add configuration to quote request