load stackup from json is too demanding

[hui-zhou-a]

Description of the feature

stackup.load is too demanding on the input json file. All material and layer properties, schemes must be defined in the json file.

for example, all of below properties must be defined in json file, but poisson_ratio is irrelevant to EM simualtion.

   "copper" = {
        "name":"copper",
        "conductivity":0,
        "loss_tangent":0,
        "magnetic_loss_tangent":0,
        "mass_density":0,
        "permittivity":1,
        "permeability":1,
        "poisson_ratio":0,
        "specific_heat":0,
        "thermal_conductivity":0,
        "youngs_modulus":0,
        "thermal_expansion_coefficient":0,
        "dielectric_model_frequency":None,
        "dc_permittivity":None,
    }

Steps for implementing the feature

No response

Useful links and references

No response