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AS9100 Rev C, ISO 9001:2008,
ISO 14001:2004 and OHSAS 18001:2007

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Scalar Feed Horn

Features:

  • Symmetric radiation pattern
  • Wide range of beamwidths
  • Low sidelobes
  • Polarization options
  • Low cross-polarization

Applications:

  • Feeds for Cassegrain antennas
  • Gaussian optics systems
  • Illumination, instrumentation
  • EW/ELINT
  • Radar systems

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Download the SFH specsheet (.pdf)

Description

Millitech series SFH scalar horn antennas are both physically and electromagnetically symmetrical, and lend themselves to either multiple polarizations or polarization-independent (scalar) operation. The suppression of E-plane wall currents provides a nearly symmetrical radiation pattern. Thus, SFH scalar horns have nearly identical beamwidths in both E- and H-planes, as well as specially-designed low sidelobes. Scalar horns are particularly suited to generating higher order modes for use in very efficient monopulse applications.

Typical radiation characteristics are shown on the following page. The on-axis cross-polarized response is low, typically -30 dB relative to the co-polarized level. The standard designs cover 26 to 325 GHz, with approximately 25º beamwidth. Custom horns can be provided with half-power (-3 dB) beamwidths from 60º to below 10º for narrow beamwidth feeds or horn-reflector antenna combinations. Multiple polarization options are available, as are full waveguide band models with single linear polarization.

Series CHA conical horn antennas are a cost-effective alternative to the scalar feedhorns, with beamwidths ranging from 10º to 60º. They have lower sidelobe levels than pyramidal horns (such as series SGH standard gain horns), because the TE 11 mode electric field distribution is tapered in both dimensions of the horn aperture. However, the beam is asymmetric in the two planes, and the sidelobes are higher than for series SFH antennas.

Standard products for both types of horn antennas have circular waveguide outputs for a given diameter. However, a rectangular waveguide output is offered using either an integral built-in step transition or a removable circular-to-rectangular transition (see series WAC).

Typical Radiation Patterns

SFH Radiation Patterns

How To Order

Specify Model Number
SFH-XX-ABBBCC (scalar horns)
CHA-XX-ABBBCC (conical horns)

XX = Waveguide Band
WR – number

A = Flange Type
R – round (not available in WR-42)
S – square (WR-42 and WR-28 only)
A – Precision Flange per Millitech IS000131, flat option (WR-08 through WR-05 only)

BBB = Circular Waveguide Diameter (in inches)
See Circular Waveguide Sizes Table (below)
Specify ØØØ for rectangular waveguide output using an integral step transition

CC = Beamwidth Degrees
ØØ – 25° beamwidth (SFH), 30° (CHA)
– 10° beamwidth (SFH)
XXN – nonstandard, specify XX as HPBW, degrees

Circular Waveguide Sizes

Rectangular Waveguide Band Circular Diameter Size Frequency Range (GHz)* Circular Waveguide Diameter (in/mm) Specify When Ordering
K Large 17.5-20.5 0.455/11.56 455
Medium 20.0-24.5 0.396/10.06 396
Small 24.0-26.5 0.328/8.33 328
Ka Large 26.5-33.0 0.315/8.00 315
Medium 33.0-38.5 0.250/6.35 250
Small 38.5-40.0 0.219/5.56 219
Q Large 33.0-38.5 0.250/6.35 250
Medium 38.5-43.0 0.219/5.56 219
Small 43.0-50.0 0.188/4.78 188
U Large 40.0-43.0 0.210/5.33 210
Medium 43.0-50.0 0.188/4.78 188
Small 50.0-60.0 0.165/4.19 165
V Large 50.0-58.0 0.165/4.19 165
Medium 58.0-68.0 0.141/3.58 141
Small 68.0-75.0 0.125/3.18 125
E Large 60.0-66.0 0.136/3.45 136
Medium 66.0-82.0 0.125/3.18 125
Small 82.0-90.0 0.094/2.39 094
W Large 75.0-88.0 0.112/2.84 112
Small 88.0-110.0 0.094/2.39 094
F Large 90.0-115.0 0.089/2.26 089
Small 115.0-140.0 0.075/1.91 075
D Large 110.0-140.0 0.073/1.85 073
Small 140.0-160.0 0.059/1.50 059
G Large 140.0-180.0 0.058/1.47 058
Small 180.0-220.0 0.045/1.14 045
--- --- 170.0-260.0 0.049/1.25 049
--- --- 220.0-325.0 0.039/0.99 039

* If the required frequencies fall within two waveguide diameter sizes, the larger one should be selected.