JED - November 2016 - 63

EW 101

Space EW - Part 6

Path Loss from Satellite
(cont'd)
By Dave Adamy

small EW antennas, this can be on the order of 10 dB,
but for typical (larger) spacecraft and ground-station
antennas, the right/left mismatch error can be more
than 30 dB. This allows the link frequency to be used

POLARIZATION LOSS
Another source of loss is from antenna polarization incompatibility. If the polarization of the signal arriving at the receiving
antenna is the same as the polarization of that antenna, there is
no polarization loss. If not, there is a polarization loss. (See Figure
1.) A complication for links between satellites and Earth stations is
that passage through the atmosphere can rotate the polarization. If
linear polarizations are used in link antennas, this rotation can cause
several dB of loss. Therefore circular polarization is usually used in
space-to-Earth-station links; the rotation of polarization through
the atmosphere then causes no link loss. Circular polarization can
be right-hand or left-hand. If the transmitting and receiving antennas are not the same, there can be significant mismatch loss. For

63

Circular
Polarization

Figure 2: Rain loss is a function of frequency and the rate of
rainfall.
3 dB
Mismatch
Loss

Large
Mismatch
Loss

Any
Linear
Polarization
XMTR or
RCVR

No Mismatch Loss

Matched
Circular
Polarization

Unmatched
Circular
Polarization

XMTR or
RCVR

The Journal of Electronic Defense | November 2016

T

he total path loss to or from a satellite includes the line-ofsight loss, atmospheric loss, antenna-misalignment loss,
polarization loss and rain loss. Last month, we covered
the line-of-sight, antenna-alignment and atmospheric loss
factors. Now, we will consider polarization mismatch and
rain attenuation.

XMTR or
RCVR

Figure 1: Satellite link polarization-mismatch loss is zero for matched circular
polarized antennas, large for mismatched circular-polarized antennas, and 3 dB
Table 1: Rain rates and fog density for each of the curves in
forFigure
circular-to-linear
polarized
antennas.
Figure 2.
1 Satellite link
polarization
mismatch loss is zero for matched circular
polarized antennas, large for mismatched circular polarized antennas, and 3 dB for
Circular to linear polarized antennas.



JED - November 2016

Table of Contents for the Digital Edition of JED - November 2016

The View From Here
Conferences Calendar
Courses Calendar
From the President
The Monitor
World Report
US Helicopter EW Programs
53rd Annual AOC International Symposium and Convention Guide
Conference Report
Threat Monitor
EW 101
AOC News
Index of Advertisers
JED Quick Look
JED - November 2016 - cover1
JED - November 2016 - cover2
JED - November 2016 - 3
JED - November 2016 - 4
JED - November 2016 - 5
JED - November 2016 - The View From Here
JED - November 2016 - 7
JED - November 2016 - Conferences Calendar
JED - November 2016 - 9
JED - November 2016 - Courses Calendar
JED - November 2016 - 11
JED - November 2016 - From the President
JED - November 2016 - 13
JED - November 2016 - 14
JED - November 2016 - The Monitor
JED - November 2016 - insert1
JED - November 2016 - insert2
JED - November 2016 - 16
JED - November 2016 - 17
JED - November 2016 - 18
JED - November 2016 - 19
JED - November 2016 - 20
JED - November 2016 - 21
JED - November 2016 - 22
JED - November 2016 - 23
JED - November 2016 - World Report
JED - November 2016 - 25
JED - November 2016 - US Helicopter EW Programs
JED - November 2016 - 27
JED - November 2016 - 28
JED - November 2016 - 29
JED - November 2016 - 30
JED - November 2016 - 31
JED - November 2016 - 32
JED - November 2016 - 33
JED - November 2016 - 34
JED - November 2016 - 35
JED - November 2016 - 36
JED - November 2016 - 53rd Annual AOC International Symposium and Convention Guide
JED - November 2016 - 38
JED - November 2016 - 39
JED - November 2016 - 40
JED - November 2016 - 41
JED - November 2016 - 42
JED - November 2016 - 43
JED - November 2016 - 44
JED - November 2016 - 45
JED - November 2016 - 46
JED - November 2016 - 47
JED - November 2016 - 48
JED - November 2016 - 49
JED - November 2016 - 50
JED - November 2016 - 51
JED - November 2016 - 52
JED - November 2016 - 53
JED - November 2016 - 54
JED - November 2016 - 55
JED - November 2016 - 56
JED - November 2016 - Conference Report
JED - November 2016 - 58
JED - November 2016 - 59
JED - November 2016 - Threat Monitor
JED - November 2016 - 61
JED - November 2016 - 62
JED - November 2016 - EW 101
JED - November 2016 - 64
JED - November 2016 - 65
JED - November 2016 - AOC News
JED - November 2016 - 67
JED - November 2016 - 68
JED - November 2016 - Index of Advertisers
JED - November 2016 - JED Quick Look
JED - November 2016 - cover3
JED - November 2016 - cover4
https://www.nxtbook.com/naylor/JEDM/JEDM0318
https://www.nxtbook.com/naylor/JEDM/JEDM0218
https://www.nxtbook.com/naylor/JEDM/JEDM0118
https://www.nxtbook.com/naylor/JEDM/JEDM1217
https://www.nxtbook.com/naylor/JEDM/JEDM1117
https://www.nxtbook.com/naylor/JEDM/JEDM1017
https://www.nxtbook.com/naylor/JEDM/JEDM0917
https://www.nxtbook.com/naylor/JEDM/JEDM0817
https://www.nxtbook.com/naylor/JEDM/JEDM0717
https://www.nxtbook.com/naylor/JEDM/JEDM0617
https://www.nxtbook.com/naylor/JEDM/JEDM0517
https://www.nxtbook.com/naylor/JEDM/JEDM0417
https://www.nxtbook.com/naylor/JEDM/JEDM0317
https://www.nxtbook.com/naylor/JEDM/JEDM0217
https://www.nxtbook.com/naylor/JEDM/JEDM0117
https://www.nxtbook.com/naylor/JEDM/JEDM1216
https://www.nxtbook.com/naylor/JEDM/JEDM1116
https://www.nxtbook.com/naylor/JEDM/JEDM1016
https://www.nxtbook.com/naylor/JEDM/JEDM0916
https://www.nxtbook.com/naylor/JEDM/JEDM0816
https://www.nxtbook.com/naylor/JEDM/JEDM0716
https://www.nxtbook.com/naylor/JEDM/JEDM0616
https://www.nxtbook.com/naylor/JEDM/JEDM0516
https://www.nxtbook.com/naylor/JEDM/JEDM0416
https://www.nxtbook.com/naylor/JEDM/JEDM0316
https://www.nxtbook.com/naylor/JEDM/JEDM0216
https://www.nxtbook.com/naylor/JEDM/JEDM0116
https://www.nxtbook.com/naylor/JEDM/JEDM1215
https://www.nxtbook.com/naylor/JEDM/JEDM1115
https://www.nxtbook.com/naylor/JEDM/JEDM1015
https://www.nxtbook.com/naylor/JEDM/JEDM0915
https://www.nxtbook.com/naylor/JEDM/JEDM0815
https://www.nxtbook.com/naylor/JEDM/JEDM0715
https://www.nxtbook.com/naylor/JEDM/JEDM0615
https://www.nxtbook.com/naylor/JEDM/JEDM0515
https://www.nxtbook.com/naylor/JEDM/JEDM0415
https://www.nxtbook.com/naylor/JEDM/JEDM0315
https://www.nxtbook.com/naylor/JEDM/JEDM0215
https://www.nxtbook.com/naylor/JEDM/JEDM0115
https://www.nxtbook.com/naylor/JEDM/JEDM1214
https://www.nxtbook.com/naylor/JEDM/JEDM1114
https://www.nxtbook.com/naylor/JEDM/JEDM1014
https://www.nxtbook.com/naylor/JEDM/JEDM0914
https://www.nxtbook.com/naylor/JEDM/JEDM0814
https://www.nxtbook.com/naylor/JEDM/JEDM0714
https://www.nxtbook.com/naylor/JEDM/JEDM0614
https://www.nxtbook.com/naylor/JEDM/JEDM0514
https://www.nxtbook.com/naylor/JEDM/JEDM0414
https://www.nxtbook.com/naylor/JEDM/JEDM0314
https://www.nxtbook.com/naylor/JEDM/JEDM0214
https://www.nxtbook.com/naylor/JEDM/JEDM0114
https://www.nxtbook.com/naylor/JEDM/JEDM1213
https://www.nxtbook.com/naylor/JEDM/JEDM1113
https://www.nxtbook.com/naylor/JEDM/JEDM1013
https://www.nxtbook.com/naylor/JEDM/JEDM0913
https://www.nxtbook.com/naylor/JEDM/JEDM0813
https://www.nxtbook.com/naylor/JEDM/JEDM0713
https://www.nxtbook.com/naylor/JEDM/JEDM0613
https://www.nxtbook.com/naylor/JEDM/JEDM0513
https://www.nxtbook.com/naylor/JEDM/JEDM0413
https://www.nxtbook.com/naylor/JEDM/JEDM0313
https://www.nxtbook.com/nxtbooks/naylor/JEDM0213
https://www.nxtbook.com/nxtbooks/naylor/JEDM0113
https://www.nxtbook.com/nxtbooks/naylor/JEDM1212
https://www.nxtbook.com/nxtbooks/naylor/JEDM1112
https://www.nxtbook.com/nxtbooks/naylor/JEDM1012
https://www.nxtbook.com/nxtbooks/naylor/JEDM0912
https://www.nxtbook.com/nxtbooks/naylor/JEDM0812
https://www.nxtbook.com/nxtbooks/naylor/JEDM0712
https://www.nxtbook.com/nxtbooks/naylor/JEDM0612
https://www.nxtbook.com/nxtbooks/naylor/JEDM0512
https://www.nxtbook.com/nxtbooks/naylor/JEDM0412
https://www.nxtbook.com/nxtbooks/naylor/JEDM0312
https://www.nxtbook.com/nxtbooks/naylor/JEDM0212
https://www.nxtbook.com/nxtbooks/naylor/JEDM0112
https://www.nxtbook.com/nxtbooks/naylor/JEDM1211
https://www.nxtbook.com/nxtbooks/naylor/JEDM1111
https://www.nxtbook.com/nxtbooks/naylor/JEDM1011
https://www.nxtbook.com/nxtbooks/naylor/JEDM0911
https://www.nxtbook.com/nxtbooks/naylor/JEDM0811
https://www.nxtbook.com/nxtbooks/naylor/JEDM0711
https://www.nxtbook.com/nxtbooks/naylor/JEDM0611
https://www.nxtbook.com/nxtbooks/naylor/JEDM0511
https://www.nxtbook.com/nxtbooks/naylor/JEDM0411
https://www.nxtbook.com/nxtbooks/naylor/JEDM0311
https://www.nxtbook.com/nxtbooks/naylor/JEDM0211
https://www.nxtbook.com/nxtbooks/naylor/JEDM0111
https://www.nxtbook.com/nxtbooks/naylor/JEDM1210
https://www.nxtbook.com/nxtbooks/naylor/JEDM1110
https://www.nxtbook.com/nxtbooks/naylor/JEDM1010
https://www.nxtbook.com/nxtbooks/naylor/JEDM0910
https://www.nxtbook.com/nxtbooks/naylor/JEDM0810
https://www.nxtbook.com/nxtbooks/naylor/JEDM0710
https://www.nxtbook.com/nxtbooks/naylor/JEDM0610
https://www.nxtbook.com/nxtbooks/naylor/JEDM0510
https://www.nxtbook.com/nxtbooks/naylor/JEDM0410
https://www.nxtbook.com/nxtbooks/naylor/JEDM0310
https://www.nxtbook.com/nxtbooks/naylor/JEDM0210
https://www.nxtbook.com/nxtbooks/naylor/JEDM0110
https://www.nxtbook.com/nxtbooks/naylor/JEDM1209
https://www.nxtbook.com/nxtbooks/naylor/JEDM1109
https://www.nxtbook.com/nxtbooks/naylor/JEDM1009
https://www.nxtbook.com/nxtbooks/naylor/JEDM0909
https://www.nxtbook.com/nxtbooks/naylor/JEDM0809
https://www.nxtbook.com/nxtbooks/naylor/JEDM0709
https://www.nxtbook.com/nxtbooks/naylor/JEDM0609
https://www.nxtbook.com/nxtbooks/naylor/JEDM0509
https://www.nxtbook.com/nxtbooks/naylor/JEDM0409
https://www.nxtbook.com/nxtbooks/naylor/JEDM0309
https://www.nxtbook.com/nxtbooks/naylor/JEDM0209
https://www.nxtbook.com/nxtbooks/naylor/JEDM0109
https://www.nxtbook.com/nxtbooks/naylor/JEDM0908
https://www.nxtbookmedia.com