Endress+Hauser Micropilot FMR56 - Beam Angle

Installation Micropilot FMR56, FMR57 FOUNDATION Fieldbus
24 Endress+Hauser
6.1.6 Beam angle
a
D
W
a
D
_
=
2
2
. .
tan
W
A0016891
 5 Relationship between beam angle α, distance D and beamwidth diameter W
The beam angle is defined as the angle α where the energy density of the radar waves
reaches half the value of the maximum energy density (3-dB-width). Microwaves are also
emitted outside the signal beam and can be reflected off interfering installations.
Beam diameter W as a function of beam angle α and measuring distance D:
FMR56
Antenna size 80 mm (3 in) 100 mm (4 in)
Beam angle α 10° 8°
Measuring distance (D) Beamwidth diameter (W)
3 m (9.8 ft) 0.53 m (1.7 ft) 0.42 m (1.4 ft)
6 m (20 ft) 1.05 m (3.4 ft) 0.84 m (2.8 ft)
9 m (30 ft) 1.58 m (5.2 ft) 1.26 m (4.1 ft)
12 m (39 ft) 2.1 m (6.9 ft) 1.68 m (5.5 ft)
15 m (49 ft) 2.63 m (8.6 ft) 2.10 m (6.9 ft)
20 m (66 ft) 3.50 m (11 ft) 2.80 m (9.2 ft)
25 m (82 ft) 4.37 m (14 ft) 3.50 m (11 ft)
30 m (98 ft) 5.25 m (17 ft) 4.20 m (14 ft)
FMR57 - Horn antenna
Antenna size 80 mm (3 in) 100 mm (4 in)
Beam angle α 10° 8°
Measuring distance (D) Beamwidth diameter W
5 m (16 ft) 0.87 m (2.9 ft) 0.7 m (2.3 ft)
10 m (33 ft) 1.75 m (5.7 ft) 1.4 m (4.6 ft)
15 m (49 ft) 2.62 m (8.6 ft) 2.1 m (6.9 ft)
20 m (66 ft) 3.50 m (11 ft) 2.80 m (9.2 ft)
30 m (98 ft) 5.25 m (17 ft) 4.20 m (14 ft)
40 m (131 ft) 7.00 m (23 ft) 5.59 m (18 ft)
50 m (164 ft) 8.75 m (29 ft) 6.99 m (23 ft)