The Trl Calibration Procedure - Agilent Technologies 8753ET User Manual

Transmission magnitude uncertainty = E
where:
E = effective directivity
D
E = effective reflection tracking
R
E = effective source match
S
E = effective load match
L
E = effective crosstalk
X
E = effective transmission tracking
T
S = S-parameters of the device under test
xx

The TRL Calibration Procedure

Requirements for TRL Standards
When building a set of TRL standards for a microstrip or fixture environment, the
requirements for each of these standard types must be satisfied.
Types Requirements
THRU
(Zero length) • No loss. Characteristic impedance (Z
• S
21
• S
11
THRU
(Non-zero
length) • Z
0
the average impedance is used.)
• Attenuation of the thru need not be known.
• If the thru is used to set the reference plane, the insertion phase or
electrical length must be well-known and specified. If a non-zero length
thru is specified to have zero delay, the reference plane is established in
the middle of the thru, resulting in phase errors during measurement of
devices.
• Reflection coefficient Γ magnitude is optimally 1.0, but need not be
REFLECT
known.
• Phase of Γ must known and specified to within ± 1/4 wavelength or
± 90°. During computation of the error model, the root choice in the
solution of a quadratic equation is based on the reflection data. An error
in definition would show up as a 180° error in the measured phase.
X
= 1 ∠0°
= S
12
= S = 0
22
of the thru must be the same as the line. (If they are not the same,
TRL*/LRM* Calibration (ES Models Only)
+ E S + E S S + E
T 21 S 11 21
) need not be known.
0
Operating Concepts
S S
L 22 21
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