SYMEO Local Positioning Radar System
Product Family LPR
®
-1DHP-200 – Product Documentation
Radar Basics
Copyright © Symeo GmbH 2018
DOC.EDO.000341.WORK.EN_LPR-1DHP-200_Product-Documentation.docx
Page 9 of 71
3.2
Radar Beam and Opening Angle
The LPR
®
-1DHP-200 emits a high frequency electromagnetic radio signal with its integrated
antenna. The EM-wave is focused by a dielectric lens and creates a radar beam with an
opening angle (half power beam width, HPBW) of +/-2,5°.
Table 3.1: Radar beam 3dB diameter vs. distance
Figure 3.1: Radar beam and opening angle.
3.3 Fresnel Zone
The area for radio transmission between two antennas is called Fresnel zone. The main part
of energy is concentrated in the first Fresnel zone.
The Fresnel zone has to be free of any obstacles to ensure that the
signal is not attenuated or interrupted.
The maximum radius of the first Fresnel zone (in the middle between two antennas) can be
calculated as follows:
= 0.5 ∙ √ ∙
is the wave length and the distance between the two radar devices or a radar device and
a reflective target For a frequency of 61 GHz a wave length of approx. 0.005 m is
calculated. The maximum radius of the first Fresnel Zone is indicated by . The maximum
radius for different distances is given in Table 3.2.
Distance d in m
1
3
10
30
50
70
100
200
300
400
600
Radar beam 3dB
diameter in m
0.1
0.3
0.9
2.6
4.4
6.1
8.7
17.5
26.2
34.9
52.4
