Keysight V3500A, User Manual

Page: 111 / 122

RF Measurement Basics 4
V3500A User’s Guide 91
If the source or load impedance is exactly equal to
Z
0
, the
corresponding reflection coefficient is zero. For simplicity,
let's assume
V
g
is defined as:
With V
g
defined as in the above equation — the source will
deliver one watt to a load of impedance Z
0
. The power
delivered to the actual load is then defined by:
Into a perfect load of impedance Z
0
, the power delivered to
the load is:
The mismatch error in the power measurement, then, is the
ratio between P
load, Z0
, and the power delivered to the actual
load presented by the power meter is defined by:
V
g
Z
g
Z
0
+
Z
0
------------------
Z
0
=
P
load
1
Γ
l
–
1
Γ
g
Γ
l
–
2
--------------------------
2
=
P
load Z
0
,
1 =
P
load meter
,
P
load Z
0
,
----------------------------
1
Γ
meter
2
–
1
Γ
g
Γ
meter
–
2
-------------------------------------
=