Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave   Antennas
  The radiation principle of travelling-wave type phase-reversal antennas is explained in details, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is point out that such magnetic dipole radiation is specific to the case of traveling-wave phase-reversal antennas whereas only electric-dipole radiation exists in resonant-type phase-reversal antennas. It is shown that a phase-reversal travelling-wave antenna alternately operates as an array of magnetic dipoles and an array of electric-dipoles during a time-harmonic period. This radiation mechanism is confirmed through both full-wave and experimental results. 
Shulabh Gupta, Li Jun Jiang and Christophe Caloz
physics.class-ph