SUBSEA EM FIELD STRENGTH vs. RANGE

attractionlewdsterΗλεκτρονική - Συσκευές

18 Οκτ 2013 (πριν από 4 χρόνια και 2 μήνες)

101 εμφανίσεις

SUBSEA EM FIELD STRENGTH vs. RANGE
1m Loop @ 1000Hz@1A
100
100
100
Frequency = 1000Hz
Wavelength = 50m
INDUCTIVE FIELD – ‘ NEAR FIELD’
Propagation Speed = 50,000 m/s
80
80
FF Loss dB/m = 1.091dB/m
QUASI-STATIC FIELD
60 RADIATION FIELD – ‘FAR FIELD’
60
HR1_dBre 1uAm
m
40
40
HR2_dBre 1uAm
m
HR3_dBre 1uAm
m
20
20
Htot_dBre1uAm
m
0
0
20
NEAR FIELD – FAR FIELD TRANSITION
-20
(~8m)
40
INDUCTIVE RADIATIVE
-40
50
3
0.1 1 10 100 1 10
0.1 d 1000
0.1m m 1000m
1m 10m 100m
Range (m )
VMD 1m 4T Loop at 1kHz 1Arms Drive, Conductivity =4S/m, E=81,
• DOES SUBSEA EM PROPAGATE ?
• RADIATION FIELD SUBJECT TO HIGH LOSS
• EM ANTENNA FIELDS HAVE 3 COMPONENTS
• … YES
• INDUCTIVE ‘NEAR FIELD’ • OHMIC LOSSES IN MEDIUM
• QUASISTATIC FIELD But
• RADIATION ‘ PROPAGATING FIELD’
• RADIATION FIELD IS STRONGEST AT RANGE • … but only just
H Field
H Field
dBre1ua/m