1. TRL
• Self Calibration
– Don’t need precise info about Standards
• Just Zo of line
– Isolation/Leakage
• Same as SOLT method
– Determine Switch terms separately
• Ratio out with 4 Receivers
– This leaves 8 error terms
– Only need S parameters of 3 independent standards to solve
1

2. (T)RL - Thru
• Thru device Insertable Thru
– Typically ports connected (Zero
length line)
– Can use Non-Zero length line L
• Reference planes are at center of
line L/2 L/2
• Useful on-wafer
DUT
• Measure 4 S-parameters
– S11, S21, S12, S22
2

3. T(R)L - Reflect
• High Reflect device
– Short or Open
– Don’t need to have model of device
• Unless using this device to establish reference planes
– Port 1 device must be equal to port 2 device
• S11 = S22
• Measure 2 S-parameters
– S11, S22
3

4. TR(L) - Line
• Delay Line
– Not required to know length accurately
• Optimal length near odd multiple of λ/4 (90 )
• Avoid lengths near 0 or 180 or even multiples of λ/4
• Ideal phase length is between 30 and 150 (5:1 BW)
• Use multiple lines to extend frequency
• Measure 4 S-parameters
– S11, S21, S12, S22
4

5. TRL
• 10 S-parameter measurements taken
– Thru (4), Reflect (2), Line (4)
• 8 Unknowns
– Actually only 7 due to ratios of b’s & a’s
• Solve for Unknowns
• Use additional information
– Determine Propagation Constant (γ) of Line
– Reflection Coefficients of Reflect Standards
5

6. TRL Advantages
• Not necessary to know details of Stds (only Zo of Line)
• Frequency does not need to be accurate, only repeatable
• Easily used in non-coaxial media
– Waveguide
– Stripline
• Zero length Thru a robust, well defined standard
• Switch Errors are removed
– Leakage
– Mismatch
– Repeatability
6