skrf.calibration.deembedding.IEEEP370_MM_NZC_2xThru¶
- class skrf.calibration.deembedding.IEEEP370_MM_NZC_2xThru(dummy_2xthru, name=None, z0=50, port_order='second', use_z_instead_ifft=False, verbose=False, forced_z0_line_dd=None, forced_z0_line_cc=None, *args, **kwargs)[source]¶
Creates error boxes from a 4-port test fixture 2xThru.
Based on [ElSA20] and [I3E370].
A deembedding object is created with a single 2xThru (FIX-FIX) network, which is split into left (FIX-1_2) and right (FIX-3_4) fixtures with IEEEP370 2xThru method.
When
Deembedding.deembed()
is applied, the s-parameters of FIX-1 and FIX-2 are deembedded from the FIX_DUT_FIX network.This method is applicable only when there is a 2x-Thru measurement.
Note
The port_order =’first’, means front-to-back also known as odd/even, while `port_order`=’second’ means left-to-right also known as sequential. `port_order`=’third’ means yet another numbering method. Next figure show example of port numbering with 4-port networks.
The scikit-rf cascade ** 2N-port operator use second scheme. This is very convenient to write compact deembedding and other expressions.
numbering diagram:
port_order = 'first' +---------+ -|0 1|- -|2 3|- +---------+ port_order = 'second' +---------+ -|0 2|- -|1 3|- +---------+ port_order = 'third' +---------+ -|0 3|- -|1 2|- +---------+
use Network.renumber to change port ordering.
Example
>>> import skrf as rf >>> from skrf.calibration import IEEEP370_MM_NZC_2xThru
Create network objects for 2xThru and FIX-DUT-FIX
>>> s2xthru = rf.Network('2xthru.s4p') >>> fdf = rf.Network('f-dut-f.s4p')
Create de-embedding object
>>> dm = IEEEP370_MM_NZC_2xThru(dummy_2xthru = s2xthru, name = '2xthru')
Apply deembedding to get the actual DUT network
>>> dut = dm.deembed(fdf)
Note
numbering diagram:
FIX-1_2 DUT FIX-3_4 +----+ +----+ +----+ -|1 3|---|1 3|---|3 1|- -|2 4|---|2 4|---|4 2|- +----+ +----+ +----+
Warning
There are two differences compared to the original matlab implementation [I3E370]:
FIX-2 is flipped (see diagram above)
A more robust root choice solution is used that avoids the apparition of 180° phase jumps in the fixtures in certain circumstances
References
[ElSA20]Ellison J, Smith SB, Agili S., “Using a 2x-thru standard to achieve accurate de-embedding of measurements”, Microwave Optical Technology Letter, 2020, https://doi.org/10.1002/mop.32098
[I3E370]https://opensource.ieee.org/elec-char/ieee-370/-/blob/master/TG1/IEEEP370mmZc2xthru.m commit 49ddd78cf68ad5a7c0aaa57a73415075b5178aa6
- Parameters:
port_order (str) –
Methods
IEEEP370_MM_NZC_2xThru De-embedding Initializer |
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Perform the de-embedding calculation |
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