Farfield Power Calculation

- April 30, 2024 at 8:33 am
  
  jimmyyclai
  Subscriber
  
  I have read this article: Understanding field polarization in far field projections – Ansys Optics. In the example file, there is a case that compares two methods to calculate the far-field power.
  Method 2 integrated the intensity of the far-field electric field (|E|^2) at the spherical coordinate and multiplied 0.5*(sqrt(eps0/mu0)). I am confused about why we need to multiply 'sqrt(eps0/mu0)'. After searching for the reference, I find another article: Changing the far field refractive index analysis object – Ansys Optics. The bottom picture shows the words.
  I remember the relationship between E & B is B=sqrt(eps0*mu0)*E. How does the magnetic field amplitude become sqrt(eps0/mu0)?
- April 30, 2024 at 5:28 pm
  
  Guilin Sun
  Ansys Employee
  
  You may need to recheck some books, as H=E/eta for plane wave and farfield where eta is the impedance sqrt(u0/eps0).
  I believe you know why there is 0.5 in front.