# Two sets of waves in a Hertzian Dipole?

1. May 29, 2009

### barton

In the near field, a hertzian pole has a changing electric field and a changing magnetic field, that are in both space and time quadrature. Are two sets of EM waves then created in the far field, one from the changing e-field, and one from the changing m-field?

2. May 29, 2009

### Bob S

There is only one radiated wave; The radiated Poynting vector P = E x H requires both an E vector and an H vector in phase. A quadrature phase field is an induction field (like in Faraday induction, where voltage is proportional to dB/dt), and cannot radiate power. The far-field radiated wave has the E vector ratio of 377:1 in the mks system. The polarization is along E.

Last edited: May 29, 2009
3. May 29, 2009

### barton

Don't the changing induction fields create the radiating far fields, as described by Maxwell's equations?

4. May 29, 2009

### Bob S

If two fields are in time (phase) quadrature, They represent energy storage, not power. The integral of [sin(wt) x cos(wt) dt] over 2 pi is zero. Consider the voltage and current for a pure inductance. They are in phase quadrature, and there is no real power.