:orphan:

How-to guides
=============

Task-oriented recipes on the public API.  Each page solves one
concrete engineering problem end to end and is meant to be adapted
rather than read in order: download it as a ``.py`` script or a
``.ipynb`` notebook and edit the parameters at the top for your own
device.  For a guided introduction to the workflow itself, start with
the tutorials instead.


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  <div id='sg-tag-list' class='sphx-glr-tag-list'></div>


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    <div class="sphx-glr-thumbnails">

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    <div class="sphx-glr-thumbcontainer" tooltip="A resonator that is coupled to the outside world does not resonate where the closed one does, and it does not store energy as long.  Both shifts matter as soon as something has to be tuned to the resonator — a particle beam driving the output cavity of a klystron has to be modelled at the loaded frequency, not at the frequency an eigenmode solve of the sealed cavity returns.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_cavity_ringdown_q_thumb.png
    :alt:

  :doc:`/howto/plot_cavity_ringdown_q`

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      <div class="sphx-glr-thumbnail-title">Ring-down: the loaded frequency and Q budget of a coupled resonator</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="Two microstrip lines running side by side for a quarter wavelength form a directional coupler: a fraction of the power entering one line leaves the near end of the other, and — ideally — nothing leaves its far end.  The classic single-section design has two knobs, the gap between the lines and their width, and one number to hit: the coupling at the centre frequency.  This guide sets a −10 dB coupler at 5 GHz on a 0.813 mm substrate and reads the result off a four-port S-parameter run.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_coupled_line_coupler_thumb.png
    :alt:

  :doc:`/howto/plot_coupled_line_coupler`

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      <div class="sphx-glr-thumbnail-title">Coupled-line directional coupler: dimensioning the pair with the port solver</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="Not every drive is a port.  Sometimes the current is the thing you know — a coil wound to a specification, an interference current measured on a harness, a lightning channel, a probe injecting a known signal — and what you want out of the simulation is the field it produces.  SourceCurrentPath says exactly that: a current I(t) prescribed along a curve through the model.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_current_path_source_thumb.png
    :alt:

  :doc:`/howto/plot_current_path_source`

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      <div class="sphx-glr-thumbnail-title">Impressed currents: driving a model with a known current</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A radiator rarely sits alone.  The antenna goes on a mast, the connector into a housing, the scatterer into a scene — and each time the whole thing is meshed together, the fine structure of the radiator sets the cell size for a domain that is mostly empty air.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_field_source_reuse_thumb.png
    :alt:

  :doc:`/howto/plot_field_source_reuse`

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      <div class="sphx-glr-thumbnail-title">Field sources: simulate a radiator once, reuse it anywhere</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A single pair of coupled microstrip lines cannot reach 3 dB coupling on a substrate anyone can fabricate — the gap would have to be a few micrometres.  Lange&#x27;s answer (1969) is to split each line into two narrow fingers and interleave them, so every finger couples to two neighbours; bond wires join the fingers of one line at both ends.  The result is a quarter-wave 3-dB quadrature coupler with fabricable gaps, the workhorse of balanced amplifiers and image-reject mixers.  This guide designs one at 10 GHz on 254 µm alumina and reads coupling, phase and match off a four-port run.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_lange_coupler_thumb.png
    :alt:

  :doc:`/howto/plot_lange_coupler`

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      <div class="sphx-glr-thumbnail-title">Lange coupler: a 3-dB interdigitated coupler dimensioned with the port solver</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A PortLumped terminates a line in a single chain of grid edges — cheap, DC-capable, and available where a waveguide port window does not fit.  The price is that it is not an exact line termination: a residual self-reflection and a phase error remain, and both depend on the grid at the gap, on the gap geometry and position, and on the port impedance.  Rules of thumb exist, but none of them tells you how good your termination is on your mesh, or up to which frequency you can trust it.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_lumped_port_investigations_thumb.png
    :alt:

  :doc:`/howto/plot_lumped_port_investigations`

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      <div class="sphx-glr-thumbnail-title">Lumped ports: investigations</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A pre-flight check for a lumped port terminating a coaxial line: fill in the given quantities of your target model, run, and the scoreboard tells you how good the termination is — worst reflection, usable band, phase error.  Edit the three knobs and re-run until the numbers meet your spec, then carry the settings over.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_lumped_port_tuning_coax_thumb.png
    :alt:

  :doc:`/howto/plot_lumped_port_tuning_coax`

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      <div class="sphx-glr-thumbnail-title">Lumped port tuning: coaxial line</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A pre-flight check for a lumped port terminating a coplanar waveguide: fill in the given quantities of your target model, run, and the scoreboard tells you how good the termination is — worst reflection, usable band, phase error.  Edit the knobs and re-run until the numbers meet your spec, then carry the settings over.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_lumped_port_tuning_cpw_thumb.png
    :alt:

  :doc:`/howto/plot_lumped_port_tuning_cpw`

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      <div class="sphx-glr-thumbnail-title">Lumped port tuning: coplanar waveguide</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A pre-flight check for a lumped port terminating a microstrip: fill in the given quantities of your target model, run, and the scoreboard tells you how good the termination is — worst reflection, usable band, phase error.  Edit the knobs and re-run until the numbers meet your spec, then carry the settings over.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_lumped_port_tuning_microstrip_thumb.png
    :alt:

  :doc:`/howto/plot_lumped_port_tuning_microstrip`

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      <div class="sphx-glr-thumbnail-title">Lumped port tuning: microstrip</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="Nothing inside a single run tells you how far its result is from the converged one.  The instrument that does is a ladder: the same model on successively finer meshes, one number read off each rung, and a stop rule for the number.  Commercial suites hide this loop behind an &quot;adaptive mesh refinement&quot; button; this page is the loop, written out, so it wraps around whatever you are simulating.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_mesh_convergence_thumb.png
    :alt:

  :doc:`/howto/plot_mesh_convergence`

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      <div class="sphx-glr-thumbnail-title">Mesh convergence: a ladder around your simulation</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A single rectangular patch is the textbook printed antenna — a half-wave resonator on a grounded substrate, 7 dBi of directivity, a few percent of bandwidth.  Four of them on a lattice of three quarters of a wavelength, fed in phase, give 13 dBi and a beam that the array factor sharpens in both planes.  This guide designs the element, then the corporate feed that splits one 50 Ω input into four equal, in-phase branches, and reads match, directivity and the two principal-plane cuts off the array run — with the element pattern times the array factor as the independent check.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_patch_array_thumb.png
    :alt:

  :doc:`/howto/plot_patch_array`

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      <div class="sphx-glr-thumbnail-title">Patch array: a 2 × 2 corporate-fed microstrip array from element to pattern</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A pair of stripline electrodes in a beam pipe is a workhorse of beam instrumentation: read out, it is a broadband pickup (a beam position monitor); driven, it is a kicker that deflects the beam.  Neither role is an S-parameter — a port model has no beam — yet both follow from one S-parameter simulation.  This guide walks the route used to design such devices (Goldberg and Lambertson, AIP Conf. Proc. 249, 537 (1992)):">

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  .. image:: /howto/images/thumb/sphx_glr_plot_stripline_pickup_kicker_thumb.png
    :alt:

  :doc:`/howto/plot_stripline_pickup_kicker`

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      <div class="sphx-glr-thumbnail-title">Striplines as pickups and kickers: beam-coupling figures from S-parameter runs</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="A run that takes an hour raises one question every few minutes: what is it doing?  The progress line in the terminal that started it answers for that terminal; a colleague&#x27;s notebook, a laptop at home, or the same notebook after the kernel was restarted all need another way in.">

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  .. image:: /howto/images/thumb/sphx_glr_plot_watch_running_simulation_thumb.png
    :alt:

  :doc:`/howto/plot_watch_running_simulation`

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      <div class="sphx-glr-thumbnail-title">Watching a simulation that is still running</div>
    </div>


.. thumbnail-parent-div-close

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    </div>


.. toctree::
   :hidden:

   /howto/plot_cavity_ringdown_q
   /howto/plot_coupled_line_coupler
   /howto/plot_current_path_source
   /howto/plot_field_source_reuse
   /howto/plot_lange_coupler
   /howto/plot_lumped_port_investigations
   /howto/plot_lumped_port_tuning_coax
   /howto/plot_lumped_port_tuning_cpw
   /howto/plot_lumped_port_tuning_microstrip
   /howto/plot_mesh_convergence
   /howto/plot_patch_array
   /howto/plot_stripline_pickup_kicker
   /howto/plot_watch_running_simulation



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 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_