pypssfss 0.1.0

Python wrapper for Julia package PSSFSS - Analysis of Polarization and Frequency Selective Surfaces

PyPSSFSS - Analysis of polarization and frequency selective surfaces in Python

PyPSSFSS is a Python package for analyzing planar polarization selective surfaces (PSSs), frequency selective surfaces (FSSs), reflectarray elements, radomes, and similar structures. It wraps the PSSFSS package which is written in the Julia programming language. Note that it is not necessary to preinstall Julia or PSSFSS before using PyPSSFSS. If Julia is not found in the user's PATH, then PyPSSFSS will install it (locally to a virtual environment, if one is active). Similarly, it will automatically install and compile PSSFSS on first use.

To use PyPSSFSS, one first specifies the geometry to be analyzed as a Python list containing two or more dielectric Layers and zero or more RWGSheet objects that define the PSS/FSS surfaces. Due to the included plot_sheet function, FSS/PSS surface triangulations can be conveniently visualized using the standard Matplotlib library. After also specifying the frequencies to be analyzed and scan angles (or unit cell incremental phasings), the user then invokes the analyze function to perform the analysis. Post-processing and plotting of results can be performed in the same Python analysis script.

Features

• Designed to be useful and accessible to working engineers and students.
• Accommodates planar FSS/PSS surfaces with no limits to number of dielectric layers or FSS/PSS sheets.
• Automatically chooses number of modes needed for cascading multiple FSS/PSS sheets using generalized scattering matrices (GSMs).
• Supports (approximate) cascading multiple sheets of different periodicities, as in a multilayer meanderline polarizer.
• Simple specification of geometry to be analyzed.
• Solution of mixed-potential integral equation using Rao-Wilton-Glisson triangle subdomain basis functions and multi-threaded method of moments.
• Fast analysis for frequency sweeps using an extremely robust rational function interpolation algorithm.
• Automatic triangulation of sheet geometries to user-specified number of triangles.
• Exploits redundancies inherent in structured meshes for greater numerical efficiency.
• Easy extraction of useful engineering performance parameters, including
  • Reflection and transmission coefficient magnitudes and/or phases for the field components of
    • TE/TM
    • Vertical/horizontal (Ludwig 3)
    • LHCP/RHCP (circular polarization)
  • Delta insertion phase delay (ΔIPD)
  • Delta insertion loss (ΔIL)
  • Axial ratio
• FSS/PSS element geometry can be exported to STL files for later import into CAD programs.
• Analysis results can be exported to
  • HFSS SBR+-compatible Fresnel tables
  • TICRA-compatible TEP (tabulated electrical properties) files.

Limitations

• Only zero-thickness FSS/PSS sheets are currently supported.
• Frequency sweeps are fastest for normal incidence or for the case where unit cell incremental phase shifts ψ₁ and ψ₂ are constant with frequency (as in a waveguide). This is due to the use of a wide-band expansion of the potential Green's functions for a stratified medium with quasi-periodic excitation. Frequency sweeps for non-normal angle of incidence are typically slower. However, as of PSSFSS version 1.1, all frequency sweeps are now much faster, often by more than an order of magnitude, compared to previous versions. The speedup is due to the use of a fast interpolated sweep by default.

Installation

Installing Using pip

pip install pypssfss

Installing from the base repository

Activate Python environment and then clone and install:

git clone https://github.com/simonp0420/pypssfss.git
cd pypssfss
pip install .

Documentation

The documentation for PyPSSFSS is here.
The documentation for the underlying Julia package PSSFSS is here. Familiarity with both of these manuals is required for use of PyPSSFSS.