36
Chapter 2
Measurement Concepts
Equations and Conversion Table
M
e
a
s
ure
m
en
t Conc
epts
Converting Return Loss to VSWR
Return loss can be expressed as a voltage standing wave ratio (VSWR)
value using the following table:
VSWR is sometimes stated as a ratio. For example: 1.2:1 “one point two
to one” VSWR. The first number is the VSWR value taken from the
table or calculated using the formula. The second number is always 1.
Table 2-1
Return Loss to VSWR Conversion
Return
Loss
(dB)
VSWR
Return
Loss
(dB)
VSWR
Return
Loss
(dB)
VSWR
Return
Loss
(dB)
VSWR
Return
Loss
(dB)
VSWR
4.0
4.42
14.0
1.50
18.0
1.29
28.0
1.08
38.0
1.03
6.0
3.01
14.2
1.48
18.5
1.27
28.5
1.08
38.5
1.02
8.0
2.32
14.4
1.47
19.0
1.25
29.0
1.07
39.0
1.02
10.0
1.92
14.6
1.46
19.5
1.24
29.5
1.07
39.5
1.02
10.5
1.85
14.8
1.44
20.0
1.22
30.0
1.07
40.0
1.02
11.0
1.78
15.0
1.43
20.5
1.21
30.5
1.06
40.5
1.02
11.2
1.76
15.2
1.42
21.0
1.20
31.0
1.06
41.0
1.02
11.4
1.74
15.4
1.41
21.5
1.18
31.5
1.05
41.5
1.02
11.6
1.71
15.6
1.40
22.0
1.17
32.0
1.05
42.0
1.02
11.8
1.69
15.8
1.39
22.5
1.16
32.5
1.05
42.5
1.02
12.0
1.67
16.0
1.38
23.0
1.15
33.0
1.05
43.0
1.01
12.2
1.65
16.2
1.37
23.5
1.14
33.5
1.04
43.5
1.01
12.4
1.63
16.4
1.36
24.0
1.13
34.0
1.04
44.0
1.01
12.6
1.61
16.6
1.35
24.5
1.13
34.5
1.04
44.5
1.01
12.8
1.59
16.8
1.34
25.0
1.12
35.0
1.04
45.0
1.01
13.0
1.58
17.0
1.33
25.5
1.11
35.5
1.03
45.5
1.01
13.2
1.56
17.2
1.32
26.0
1.11
36.0
1.03
46.0
1.01
13.4
1.54
17.4
1.31
26.5
1.10
36.5
1.03
46.5
1.01
13.6
1.53
17.6
1.30
27.0
1.09
37.0
1.03
47.0
1.01
13.8
1.51
17.8
1.30
27.5
1.09
37.5
1.03
47.5
1.01