Following a procedure similar to BI-RME , an integral equation approach is formulated to calculate [[psi].sup.S.sub.[beta]]( [bar.[rho]]) by using the [g.sup.[OMEGA].sub.H] (k, [bar.[rho]], [bar.[rho]]') with low wavenumber extraction and equivalent sources on [sigma].
The method of DC extraction is used in BI-RME  for the cases of rectangular waveguide and circular waveguide.
Perregrini, "The BI-RME method: An historical overview," 2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO), May 14-16, 2014.