This module allows you to do antenna simulations in Python using the nec2++ antenna simulation package. This is a wrapper using SWIG of the C interface, so the syntax is quite simple. Have a look at the file necpp_src/example/test.py, for an example of how this library can be used.

Tim Molteno. [email protected]

• Version 1.7.0 includes support for getting elements of radiation patterns. At the moment this is just through the function nec_get_gain().
• Version 1.7.0.3 includes nec_medium_parameters(). You could simulate an antenna in seawater!

As of version 1.6.1.2 swig is no longer required for installation. Simply use PIP as follows:

pip install necpp

Try help(necpp) to list the available functions. The functions available are documented in the C-style API of nec2++. This is available here

The following code calculates the impedance of a simple vertical monopole antenna over a perfect ground.

import necpp

def handle_nec(result):
  if (result != 0):
    print necpp.nec_error_message()

def impedance(frequency, z0, height):
  
  nec = necpp.nec_create()
  handle_nec(necpp.nec_wire(nec, 1, 17, 0, 0, z0, 0, 0, z0+height, 0.1, 1, 1))
  handle_nec(necpp.nec_geometry_complete(nec, 1, 0))
  handle_nec(necpp.nec_gn_card(nec, 1, 0, 0, 0, 0, 0, 0, 0))
  handle_nec(necpp.nec_fr_card(nec, 0, 1, frequency, 0))
  handle_nec(necpp.nec_ex_card(nec, 0, 0, 1, 0, 1.0, 0, 0, 0, 0, 0)) 
  handle_nec(necpp.nec_rp_card(nec, 0, 90, 1, 0,5,0,0, 0, 90, 1, 0, 0, 0))
  result_index = 0
  
  z = complex(necpp.nec_impedance_real(nec,result_index), 
              necpp.nec_impedance_imag(nec,result_index))
  
  necpp.nec_delete(nec)
  return z

if (__name__ == 'main'):
  z = impedance(frequency = 34.5, z0 = 0.5, height = 4.0)
  print "Impedance \t(%6.1f,%+6.1fI) Ohms" % (z.real, z.imag)

Have a look at [http://github.com/tmolteno/necpp] for more information on using nec2++.