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(1.5kW to 3kW, Convection and Watercooled)

Standard Fixed Loads
The waveguide loads devices are manufactured from selected waveguide tube. The flange interface is precisely controlled to offer the optimum performance.

Sliding Loads
The standard sliding loads are assembled in the same way as the standard fixed loads using selected waveguide tube and precise positioning of the flange interface. Operation of the sliding element is by a push/pull mechanism and a locking screw is provided for repetitive measurements.

High Power Loads
High and medium power loads are based on silicon carbide elements for optimum thermal efficiency. Several sizes of loads per waveguide size may be available depending on the power requirement.

Sliding Loads

Standard Rectangular

V.S.W.R: See table (based on spot frequency operation)
Material: Brass
Load material: Iron loaded resin
Finish: Blue paint

Operating Frequency Band (GHz)Waveguide DesignationMax V.S.W.R.Max Power Watts C.W.Overall Length “A” (mm)
2.60 – 3.9510322841.013790
3.30 – 4.9011A402291.012526
3.95 – 5.8512481871.012414
4.90 – 7.0513581591.012332
5.85 – 8.2014701371.011336
7.05 – 10.015841121.011323
8.20 – 12.4016100901.010.8331
10.0 – 15.017120751.010.8321
12.4 – 18.018140621.010.6321
15.0 – 22.019180511.020.6225
18.0 – 26.520220421.020.6107
22.0 – 33.021260341.020.6107
26.5 – 40.022320281.0350.5100

Fixed Loads

Standard Rectangular

Material: Brass
Load material: Iron loaded resin
Finish: Blue paint

Calibration quality fixed loads

Operating Frequency Band (GHz)Waveguide DesignationMax V.S.W.R.Max Power Watts C.W.Overall Length “A” (mm)
2.60 – 3.9510322841.025310
3.30 – 4.9011A402291.024225
3.95 – 5.8512481871.023.5235
4.90 – 7.0513581591.023.5190
5.85 – 8.2014701371.022185
7.05 – 10.015841121.022143
8.20 – 12.4016100901.021.3138
10.0 – 15.017120751.021.3127
12.4 – 18.0 18140621.02186
15.0 – 22.019180511.025179
17.7 – 26.520220421.0350.894
22.0 – 33.021260341.0350.867
26.5 – 40.022320281.050.666

Double Ridge

Material: Aluminium
Load material: Iron loaded resin
Finish: Blue paint,  iridited flanges

Operating Frequency Band (GHz)Waveguide DesignationTWS Part Number Max V.S.W.R.Max Power Watts C.W.Overall Length “A” (mm)
4.75 – 11.0WRD475 D241.0411386
5.8 – 16.0WRD580 D281.048300
6.5 – 18.0WRD650 D281.057252
7.5 – 18.0WRD750 D241.057237
18.0 – 40.0WRD180 C241.065128

High Power Fixed Loads

The range of high power waveguide loads is continually being expanded. The power rating depends on the waveguide size, ambient temperatures and the fin area available, (e.g. the two WG17 loads shown below have power ratings of 800W and 500W and the WG10 load 2000W), but for very high power requirements, either multiple load elements and internal power splitters or a custom load element is designed in house for optimum heat distribution. Special designs are available for requirements with extremely high peak powers.

All load elements are made from silicon carbide which is thermally bonded to the heatsink and have a match better than 1.1:1.

The majority of loads have optimum heat dissipation when mounted horizontally, but fin arrangements are also available for vertical mounting - if necessary (at extra cost). Please consult the factory for higher power ratings and support bracketry.

Load sizes vary enormously depending on power dissipation and if forced air or convection is used - but as a very rough guide, the approximate size of a 1kW load using convection would be 220 x 220 x 300mm and a 2kW load 255 x 255 x 550mm

Designs are available for waveguide sizes WG10 to WG22 in various power ratings. Please contact the factory with the waveguide size, power dissipation and frequency range needed (it is often possible to optimise performance over a particular frequency range when very high power loads are needed).

Ordering information


Product code
FL = fixed load
SL =  sliding load


Waveguide size
British WG size for rectangular waveguide or MIL spec. WRD size for double ridge waveguide
e.g. 16 = WG16; 750 = WRD750


S = standard
H = high power


Z = unpainted (standard)
Q = TWS blue (preferred)
B = black
G grey


Z = unplated (standard for brass)
M = passivate (option for brass)
F = Iridite (preferred for aluminium)
H = chromate
A = tin
B = silver


Flange type
Last 3 digits from the TWS flange part no.
e.g. 402 = UBR flange


A = aluminium (standard for double ridge)
B = brass (standard for rectangular)