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    Modeling an ISM 433MHz Helical Antenna with AN-SOF.
    25Feb, 2022
    ISM 433MHz Helical Antenna

    Small helical antennas for the 433 MHz ISM band are a good example where we need advanced software that has the ability to model: 

    • curved wires with exact description of the helix contour
    • very close wires, spaced a fraction of the wire radius
    • horizontal wires almost touching the ground plane
    • bent wires at right angles or less
    • short segments, below 0.001 wavelength
    • thick wires by means of Exact Kernel instead of thin-wire approximation

    AN-SOF includes all these features.

    In this example, a perfect ground plane is used to get the input impedance: 48 Ohm, very close to the 50 Ohm of the antenna datasheet. We must subtract 3 dBi from the gain to obtain the gain in free space. It is a simple model, but it coincides very well with reality.

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    Modeling an ISM 433MHz Helical Antenna with AN-SOF.
    Modeling an ISM 433MHz Helical Antenna with AN-SOF.

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    Blog > Antennas and Beyond!

    Modeling an Array of Snowflake Quads with AN-SOF.
    20Feb, 2022
    Array of Snowflake Quads

    Nathan Cohen in the US fractalized the quad loop based on the Minkowski square and invented an array of two elements. The biggest advantage of fractal antennas is that we get a wide bandwidth with a small size.

    This simulation shows that we can almost double the bandwidth with a 3-element array. It has a reflector, a driven element, and a director. These are the results for the 20 m band (~ 14 MHz),

    Quad size ~ 290 x 290 cm (0.14 x 0.14 of a wavelength)

    Element spacing ~ 280 cm

    450 KHz bandwidth (VSWR < 2) around 14.5 MHz

    6 dBi gain

    10 dB F/B

    80° beamwidth

    Vertical polarization

    It has less gain than could be achieved with a 3-element Yagi, but it has a relatively large bandwidth and is a very compact antenna. It does not need a matching circuit and its impedance is 50 Ohm at resonance, so it could be fed directly through a 50 Ohm coax.

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    Modeling an Array of Snowflake Quads with AN-SOF.
    Modeling an Array of Snowflake Quads with AN-SOF.

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    Blog > Antennas and Beyond!

    New release of Antenna Simulation Software: AN-SOF 7.0
    14Feb, 2022
    AN-SOF 7.0 is Here!
    • Run bulk simulations and process multiple input files with just one click. We have chosen the NEC format for the input files as it is a standard adopted by many users. Forget about running the simulations one by one, run them all at once.
    • Import a single input file as a bulk simulation and get all the output data in one step. All computed parameters are saved as CSV files (power budget, gain, input impedance, VSWR, far and near fields, etc.).
    • Export AN-SOF designs to Scilab format (*.sce files) and easily develop scripts that generate multiple descriptions with variable geometric parameters.

    And last but not least, in this link > you will find the model of a Yagi-Uda antenna with variable element spacing. Follow the instructions therein and run the scripts to get the gain of a 3-element Yagi antenna as a function of the element spacing.

    Enjoy!

    New release of Antenna Simulation Software: AN-SOF 7.0
    New release of Antenna Simulation Software: AN-SOF 7.0

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    Blog > Antennas and Beyond!