Endress+Hauser Micropilot FMR51 - Beam Angle

Micropilot FMR51, FMR52 FOUNDATION Fieldbus Installation
Endress+Hauser 23
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:
FMR51
Antenna size 40 mm (1½ in) 50 mm (2 in) 80 mm (3 in) 100 mm (4 in)
Beam angle α 23° 18° 10° 8°
Measuring
distance (D)
Beamwidth diameter W
3 m (9.8 ft) 1.22 m (4 ft) 0.95 m (3.1 ft) 0.53 m (1.7 ft) 0.42 m (1.4 ft)
6 m (20 ft) 2.44 m (8 ft) 1.9 m (6.2 ft) 1.05 m (3.4 ft) 0.84 m (2.8 ft)
9 m (30 ft) 3.66 m (12 ft) 2.85 m (9.4 ft) 1.58 m (5.2 ft) 1.26 m (4.1 ft)
12 m (39 ft) 4.88 m (16 ft) 3.80 m (12 ft) 2.1 m (6.9 ft) 1.68 m (5.5 ft)
15 m (49 ft) 6.1 m (20 ft) 4.75 m (16 ft) 2.63 m (8.6 ft) 2.10 m (6.9 ft)
20 m (66 ft) 8.14 m (27 ft) 6.34 m (21 ft) 3.50 m (11 ft) 2.80 m (9.2 ft)
25 m (82 ft) 10.17 m (33 ft) 7.92 m (26 ft) 4.37 m (14 ft) 3.50 m (11 ft)
30 m (98 ft) - 9.50 m (31 ft) 5.25 m (17 ft) 4.20 m (14 ft)
35 m (115 ft) - 11.09 m (36 ft) 6.12 m (20 ft) 4.89 m (16 ft)
40 m (131 ft) - 12.67 m (42 ft) 7.00 m (23 ft) 5.59 m (18 ft)
45 m (148 ft) - - 7.87 m (26 ft) 6.29 m (21 ft)
60 m (197 ft) - - 10.50 m (34 ft) 8.39 m (28 ft)
70 m (230 ft) - - - 9.79 m (32 ft)