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

Parameters:

port_order (str) –

Methods

__init__

IEEEP370_MM_NZC_2xThru De-embedding Initializer

deembed

Perform the de-embedding calculation

split2xthru