Scikit-rf

This new release adds the following new features and improvements:

New Features or important improvements
* Interpolation improvements by Ttl in https://github.com/scikit-rf/scikit-rf/pull/595
* MTRL fixes by Ttl in https://github.com/scikit-rf/scikit-rf/pull/601 (and #602 and 603)
* multi-parameters NetworkSet and CITI and GMDIF file import by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/585 (see #584 for more details)
* HP8510C Drivers and VISA Bugfixes by jjoonathan in https://github.com/scikit-rf/scikit-rf/pull/591
* Speed up Circuit class by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/575
* Speed up vector fitting by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/605

Bug fixes and other improvements
* Fix/dc extrapolation array by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/571
* Correct error when asking db/ma from ri file by edumur in https://github.com/scikit-rf/scikit-rf/pull/588
* Fix coefs_8term and coefs_12term by Ttl in https://github.com/scikit-rf/scikit-rf/pull/589
* fix reading ISO-8859-1 encoded Touchstone file and add encoding param to Network() and Touchstone() by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/587
* Vector Fitting: Notation and other minor improvements by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/577
* Don't initialize z0 from str by Ttl in https://github.com/scikit-rf/scikit-rf/pull/598
* Don't modify apply_cal input network by Ttl in https://github.com/scikit-rf/scikit-rf/pull/602
* Remove confusing transposes by Ttl in https://github.com/scikit-rf/scikit-rf/pull/603

Documentation
* Vector Fitting: Example notebooks and docstrings by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/567
* Documentation fixes by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/576
* Change syntax of the images from Markdown to HTML in the de-embedding tutorial by keikawa in https://github.com/scikit-rf/scikit-rf/pull/580
* Add citation to the IEEE journal article by temmeand in https://github.com/scikit-rf/scikit-rf/pull/581
* Fix citation formatting that was a run-on line by temmeand in https://github.com/scikit-rf/scikit-rf/pull/582
* DOI hyperlink and minor fixes in docs by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/583
* Doc corrections & example snippets by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/599

CI
* Separate the test of the notebooks from the test of the code by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/578
* Try to fix coverall stats by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/568

New Contributors
* jjoonathan made their first contribution in https://github.com/scikit-rf/scikit-rf/pull/591

A lot of changes in this new version!

New Features
* DC extrapolation is now possible for noisy networks (Fix/518 by FranzForstmayr)
* Add Open, SeriesImpedance and ShuntAdmittance classmethods to Circuit by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/529
* LRRM calibration by Ttl in https://github.com/scikit-rf/scikit-rf/pull/530
* LRM calibration by Ttl in https://github.com/scikit-rf/scikit-rf/pull/532
* Add thru-only de-embedding methods by keikawa in https://github.com/scikit-rf/scikit-rf/pull/557
* Vector Fitting: Speed improvements by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/559
* Allow to calculate step/impulse response from multiports by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/564


Documentation
* New documentations on De-embedding Class by vik-s 516
* Update Networks.ipynb by snowflakeas in https://github.com/scikit-rf/scikit-rf/pull/536
* Fix Circuit docstrings by Ttl in https://github.com/scikit-rf/scikit-rf/pull/541
* Multiline TRL documentation improvements by Ttl in https://github.com/scikit-rf/scikit-rf/pull/552
* LRRM, MTRL doc fixes by Ttl in https://github.com/scikit-rf/scikit-rf/pull/555
* Extend user info in docstring of Network.delay() by Vinc0110 in https://github.com/scikit-rf/scikit-rf/pull/556
* Fix DefinedAEpTandZ0 example by Ttl in https://github.com/scikit-rf/scikit-rf/pull/561

Bug Fixes and improvements
* Clean up legacy code by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/520
* Warn if invalid frequency data is detected and method to fix the data by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/523
* logging error is never thrown if passivity enforcement does not converge. by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/526
* NISTMultilineTRL fix for non-zero thru by Ttl in https://github.com/scikit-rf/scikit-rf/pull/533
* Fix problem with one-port subnetworks overwriting others for nports>10 by JAnderson419 in https://github.com/scikit-rf/scikit-rf/pull/540
* Fix some deprecation warnings with Python3.9 by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/542
* Assert that the name of the Port contains 'port' by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/551
* Zipped touchstone fix by stevehamblin in https://github.com/scikit-rf/scikit-rf/pull/548
* Warn user if no Frequency set when cascading by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/550
* Minor fixes to the de-embedding API by keikawa in https://github.com/scikit-rf/scikit-rf/pull/562
* Warn users about future change of 'extrapolate_to_dc' default value from rational to cubic by jhillairet in https://github.com/scikit-rf/scikit-rf/pull/563


Other things that Changed
* Clean up legacy code by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/520
* Clean up disabled calibration tests by Ttl in https://github.com/scikit-rf/scikit-rf/pull/531
* Pytest instead of nose by FranzForstmayr in https://github.com/scikit-rf/scikit-rf/pull/560


New Contributors
* snowflakeas made their first contribution in https://github.com/scikit-rf/scikit-rf/pull/536
* stevehamblin made their first contribution in https://github.com/scikit-rf/scikit-rf/pull/548

**Full Changelog**: https://github.com/scikit-rf/scikit-rf/compare/v0.19.0...v0.20.0

A lot of work has been done these last month on scikit-rf, many thanks to all contributors. This new version brings some new features, bug fixes and a lot of improved documentation.

New Features
--------------
- Implementation of a deembedding class 480 by vik-s
- Add VNA Keysight n9918a for usage in data_grabber.py 482 by wbarnha
- Add `stdev` function, organize file, allow `read_all()` to recursively check directories 485 by wbarnha
- Add functionality to plot group delay for multiple files simultaneously 489 by wbarnha
- two new features to the `VectorFitting` class 498 from Vinc0110 :
- Evaluation of model passivity (functions `passivity_test()` and `is_passive()`)
- Enforcement of model passivity (function `passivity_enforce()`)

Improvements
---------------
- Updated continuous integration, RTD setup and package dependencies in 494 and 501 by Vinc0110
- Support of Python 3.9 in 507 by jhillairet
- Single Ended to Mixed Mode conversion now can usereference impedance different from 50 Ohms 510 by FranzForstmayr

Documentation
----------------
- Fix a lot of typos in the code docstring 484 and notebooks 491 by nikosavola
- Improve docstring for `Network.renumber` and many other things in 504 by jhillairet
- various documentation improvements in 490 by jhillairet
- wiki was deleted and its content was moved to main documentation 500 by jhillairet
- improve a lot of dosctring and type hints in 504, 505 and 506 by Vinc0110 and jhillairet
- Example for tapered transmission line 511 by jhillairet

Bug Fixes
----------
- Fix bug 299 (offset in time vector) in 488 by FranzForstmayr
- Fix bug 467 (`is_symmetric`) in 502 by Vinc0110

This release contains bug fixes:

- FranzForstmayr removed pandas dependency
- luar123 fixed a relative import
- Vinc0110 fixed a typo in SPICE .SUBCKT

This new version of scikit-rf includes multiple bug fix and changes under-the-hood, that should not affect users except for users of the `connect()` method with N-port Network.

`Connect`
The automated port renumbering in `connect()` was quite unintuitive since 2020 and has been corrected in 448 by hohe. To make things as clear as possible, [special tutorial dedicated to Network connections](https://scikit-rf.readthedocs.io/en/latest/tutorials/Connecting_Networks.html) has been added to the documentation (jhillairet).

Vector Fitting
* 469 & 473 Vinc0110 fixes two bugs in the vector fitting algorithm and adds some documentation and tests.
* FranzForstmayr removed the mandatory matplotlib dependency in Vector Fitting in 444
* following a suggestion in the mailing-list Vinc0110, added optional Axes parameters to the plotting functions in vectorFitting.py to control the output with matplotlib in 450.

Type Hints
* FranzForstmayr in 451 updated a lot of the function & method definitions to add type hints to improve the quality of the autosuggestions in IDEs.

Documentation
* NikoDaGreat Fixed math typesetting in `network.chopinhalf` in 465
* jhillairet refreshed the main Github welcome page in 445. In addition, please note that a [suggestion box](https://docs.google.com/forms/d/e/1FAIpQLSfkSNy8KzoHwdDxYGCmHHiA3GsHgN6zKTFI2NrcUR29U7Xx6A/viewform) has been added: please send us your suggestions/wishes/comments!
* NikoDaGreat fixed some typos in 446
* jhillairet correct documentation figures in 452 and 453

Improvements and bug fix
* 442 : wbarnha added an option for renaming files in the Qt NetworkList widget
* 447 : improve Binder graphical compatibility by jhillairet
* 445 FranzForstmayr improved the Z0 setter/getter and also add new tests detailed the various cases
* 457 FranzForstmayr (contributor of the month!) fixed reading HFSS files from StringIO.
* 458 + 459 jhillairet fix NetworkSet zip file reading bug introduced by StringIO compatibility + add NetworkSet tests and fix continuous integration of the notebooks
* 460 Vinc0110 fixes the generated API docs of the VectorFitting class, which were missing the plotting functions.
* 461 FranzForstmayr update and tests to mathFunctions.py
* 472 luar123 fixes a bug in write_touchstone when the port names are written: The first port should be Port[1] instead of Port[0].

The support of Python 2.7 has been dropped with this version (PR436 from JAnderson419). For the moment, only the Travis and GitHub Actions testing have been dropped, the Python2 parts of code still exist and remain to be cleaned one day.

New Features
subnetwork
Creating the `rf.subnetwork()` function and `Network.subnetwork()` method for creating sub-Network for a given list of port indices. (PR 423 from jhillairet)

As an illustration, below three 2ports subnetwork are extracted from a reference 3ports Network. These 3 subnetworks are after recombined into a 3ports Network.

python
import skrf as rf

3 port Network
tee = rf.data.tee
2 port Networks as if one measures the tee with a 2 ports VNA
tee12 = rf.subnetwork(tee, [0, 1]) 2 port Network from ports 1 & 2, port 3 matched
tee23 = rf.subnetwork(tee, [1, 2]) 2 port Network from ports 2 & 3, port 1 matched
tee13 = rf.subnetwork(tee, [0, 2]) 2 port Network from ports 1 & 3, port 2 matched

recreate the original 3 ports Network from the thee 2-port sub-Networks
ntw_list = [tee12, tee23, tee13]
tee2 = rf.n_twoports_2_nport(ntw_list, nports=3)
print(tee2 == tee) --> True


Circular waveguide media (`media.CircularWaveguide`)
* Added circular waveguide (single mode homogeneous filled) Media from scimax (PR 376). Also made some corrections to some rectangular waveguide formuale (cutoff)
python
In the following example an ideal waveguide of 2.39 mm diameter is
constructed for the high W band, operated in the fundamental TE11 mode.
If no conductivity is provided the walls are treated as perfect
electric conductors.
freq = rf.Frequency(88,110,101,'ghz')
rf.CircularWaveguide(freq, r=0.5 * 2.39e-3)


Improvements of existing features
* Network() can now supports StringIO for filename from arsenovic (PR 433)

* write port names to Touchstone files (as comment) from luar123 (PR 428

* Improve Error handling for step/impulse responses from FranzForstmayr (PR 435, fixes 434). Now throws a:
- `ValueError` if one wants to calculate step or impulse response with an Network with more than one port
- `NotImplementedError` if one wants to calculate step or impulse response If used with non equidistant sampled frequency vector

Documentation
* Fixing documentation notebooks from jhillairet (PR 425)

* Notebook tests are included using nbsmoke (but do not count for coverage) from ema00 (PR424, fixes partly 114)

* Documentation improvements from arsenovic (PR 433)

Fixed Bug
* Use relative paths for import from luar123 (PR 438)
* Fix `rf.io.Touchstone.get_comment_variables()` which was cropping decimals from JAnderson419 (PR 427, fixes 426 )

* Matplotlib backend reconfiguration from Vinc0110 (PR 420, fixes 419):
* Disabling the matplotlib backend reconfiguration in plotting.py (Edit: keeping it for Python2)
* Disabling invalid parameter interactive from matplotlib stylesheets, which were causing warnings in skrf.stylely()