Datasheet
12
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S15E.pdf
08.10.31
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4
Applications
5. Sharpening of Radiation
When there are objects within the sensors field that
reflect ultrasonic waves but when only a specific object
should be detected, more acute radiation of ultrasonic
waves is advantageous. Radiation is determined by the
dimensions of the ultrasonic radiation surface and the
frequency, but it is possible to make radiation more
acute and measuring distance longer by mounting a
horn on the outside of the ultrasonic sensor.
Regarding this horn, in general, the wider the diameter
of its opening and the longer its total length, the more
acute the radiation.
The relationship between the configuration of the horn
using MA40S4R/S and the radiation characteristics is
shown in Figs. 19 and 20.
A similar result can be obtained regarding sound pres-
sure radiation.
θ
=10
θ
90
60
30
0
-10
-20
-30
90
60
30
ℓ
=
40
ℓ
=
30
ℓ
=
20
ℓ
Sensor only
D
d
d=ø10
Attenuation (dB)
Fig. 19 Horn Length and Radiation (MA40S4R)
90
60
30
0
-10
-20
-30
90
60
30
ℓ
Sensor only
D
d
d=ø10
ℓ
=
30mm
Attenuation (dB)
θ
θ
=
30
θ
=
20
θ
=
10
Fig. 20 Horn Angle and Radiation (MA40S4R)
R
(mm)
20
30
40
θ
1
/2 :
Half attenuation angle
D
(mm)
17
21
24
θ
1
/
2
(deg)
50
35
28
18
θ
(deg)
10
20
30
D
(mm)
21
32
45
θ
1
/
2
(deg)
50
28
16
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