Ferrite-Cored Patch Antenna With Suppressed Harmonic Radiation

We designed and fabricated a multiple-ferrite-cored patch antenna (MFC-PA) to suppress harmonic radiation over the frequency range of 1–10 GHz and obtain wide suppressing bandwidth. Its suppression performance was compared to those of the conventional PA, photonic bandgap PA (PBG-PA), and defected ground structure PA (DGS-PA). Simulated and measured results show that MFC-PA effectively suppresses harmonic radiation up to
$5.6f_{0}$
, where
$f_{0}$
is 0.9 GHz, while the harmonic radiation of PBG-PA and DGS-PA is suppressed up to
$3f_{0}$
. It is suggested by the antenna performance simulation that MFC-PA can further suppress harmonic radiation up to
$11f_{0}$
. In principle, the harmonic radiation of MFC-PA is suppressed by dissipating the unwanted signals in ferrite materials, whereas PBG-PA and DGS-PA suppress harmonic radiation by reflecting or redirecting unwanted signals, which is not desired. Ferrite loading is a unique approach to suppress any harmonic radiation.