Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas

The radiation principle of traveling-wave-type phase-reversal antennas is explained in detail, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is pointed 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 traveling-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.