Endress+Hauser Micropilot FMR20 - Page 17

Micropilot FMR20 Modbus RS485 Installation
Endress+Hauser 17
5.1.5 Beam angle
_
2
α
W = 2 × D × tan
α
D
W
A0046285
 8 Relationship between beam angle α, distance D and beamwidth diameter W
The beam angle is defined as the angle α at which the power energy of the radar waves
reaches half the value of the maximum power density (3dB 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 distance D.
80 mm (3 in) antenna with or without a flooding protection tube, α 12 °
W = D × 0.21