Heavi

Heavi is a Python-based circuit simulation library designed for efficient modeling and analysis of linear components. It allows users to build circuits programmatically, run analyses (such as S-parameters), and visualize results. Currently, the library supports only linear components but provides a foundation for advanced circuit simulations.

Features

• Linear Component Simulation: Model circuits with resistors, capacitors, and inductors.
• Custom Filters: Create filters (e.g., Cauer, Chebyshev) with ease.
• S-Parameter Analysis: Perform S-parameter analysis on two-port networks.
• Visualization Tools: Plot S-parameters with customizable options.
• Programmatic Circuit Building: Construct circuits directly in Python for maximum flexibility.

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Installation

For now, clone the repository and install locally:

pip install heavi

Optionally, its easier to just download the

Getting Started

Here is an example that demonstrates building a simple two-port circuit with a 4th-order bandpass filter, running S-parameter analysis, and plotting the results.

import heavi as hv
from heavi.lib import smd
# Create a new circuit model
model = hv.Model()

# Define circuit nodes and terminals
n1 = model.node()
p1 = model.new_port(50, n1)  # Terminal 1 with 50-ohm impedance
n2 = model.node()
n3 = model.node()
p2 = model.new_port(50, n3)  # Terminal 2 with 50-ohm impedance

# Add a resistor between nodes n2 and n3
resistor = smd.SMDResistor(5, hv.lib.smd.SMDResistorSize.R0402).connect(n2, n3)

# Add a 4th-order bandpass filter between ground and node n1, connecting to n2
model.filters.cauer_filter(
    model.gnd, n1, n2, 2e9, 70e6, 5, 0.03, hv.FilterType.CHEBYCHEV, type=hv.BandType.BANDPASS
)

# Define the frequency range for S-parameter analysis
f = hv.frange(1.8e9, 2.2e9, 2001)

# Perform S-parameter analysis
S = model.run_sp(f)

# Plot S-parameters
hv.plot_s_parameters(f, [S.S11, S.S21], labels=["S11", "S21"], linestyles=["-", "-"], colorcycle=[0, 1])

# Print all components in the model
model.print_components()

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API Reference

heavi.Model

The Model class is the central interface for building and simulating circuits. It inherits from the Network class and has additional libraries for component creation.

Initialization

Model(default_name: str = "Node", filter_library: Filtering = Filtering)

• default_name: Default prefix for node names.
• filter_library: Library for filter definitions.

Key Methods

Most of the methods mentioned below are defined as Network methods.

• node(name: str = None) -> Node Creates a new circuit node.

• new_port(signal_node: Node, Z0: float, gnd_node: Node = None) -> Port Adds a terminal to the circuit with a specified impedance.

• resistor(node1: Node, node2: Node, R: float) -> Component Adds a resistor between two nodes.

• capacitor(node1: Node, node2: Node, C: float) -> Component Adds a capacitor between two nodes.

• inductor(node1: Node, node2: Node, L: float) -> Component Adds an inductor between two nodes.

• transmissionline(gnd: Node, port1: Node, port2: Node, Z0: float, er: float, L: float) -> Component Adds a transmission line with specified properties.

• run(frequencies: np.ndarray) -> Sparameters Runs S-parameter analysis for the specified frequency range.

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heavi.Network

The Network class provides foundational methods for building and analyzing circuits.

Initialization

Network(default_name: str = 'Node')

• default_name: Default prefix for node names.

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heavi.plot_s_parameters

The plot_s_parameters plot function uses matplotlib and offers a convenient means of displaying S-parameters.

hv.plot_s_parameters(frequencies: np.ndarray, S_parameters: list[np.ndarray], labels: list[str], linestyles: list[str], colorcycle: list[int])

Plots S-parameter data.

Parameters:

• frequencies: Frequency range in Hz.
• S_parameters: List of S-parameter arrays.
• labels: Labels for each plot line.
• linestyles: Line styles for each plot line.
• colorcycle: List of color indices for the plot.

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heavi.sparam.Sparameters

The Sparameters class encapsulates the results of S-parameter analysis and mostly just contains the S-parameters as a 3-dimensional numpy array with the first two dimensions being the S-parameter matrix and the last the frequency axis.

Attributes

• S: S-parameter matrix.
• frequencies: Frequency range associated with the analysis.

Properties

All possible S-parameters up to a 5-port network are predefined as properties for quick access and auto-completion purposes.

• S11: The S11 array data.
• S12: The S12 array data.
• S55: The S55 array data.

Important Methods

Most of the methods mentioned below are defined as Network methods.

• S(i: int, j: int) -> np.ndarray Returns the Sij component of the S-matrix.

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For more advanced usage, refer to the inline documentation in the heavi package or the source code.

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Visualization

The hv.plot_s_parameters() function provides an easy way to visualize S-parameter data:

hv.plot_s_parameters(frequencies, [S11, S21], labels=["S11", "S21"], linestyles=["-", "--"], colorcycle=[0, 1])

• frequencies: Frequency range (Hz).
• S-parameters: A list of S-parameters to plot.
• labels: Labels for each plot line.
• linestyles: Line styles for each plot.
• colorcycle: Color indices for the lines.

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Features

• Touchstone import
• Stochastic components and system modeling.
• Most common components, impedance, admittance, port, capacitor, inductor, transmission line and N-port S-parameters.
• BaseCompont class for custom library creation
• Cauer filter design automization (Low, high and bandpass Chebychev and Maximally flat).
• Impedance transformers (Chebychev only)

Future features

• Advanced PCB Router
• Larger library of components and predefined interfaces/functions
• Support for nonlinear components (e.g., transistors, diodes).
• Time-domain simulations.
• Enhanced visualization capabilities.

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Contributing

Contributing options come later. Please reach out via my website: www.emerge-software.com

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License

This project is licensed under the MIT License. See the LICENSE file for details.