Harmonic Suppressed Slot Loop Antenna Fed by Coplanar Waveguide

A harmonic suppressed coplanar waveguide (CPW)-fed slot-coupled circular slot loop antenna is proposed. Two coupling slots placed inside the radiating slot loop and connected directly to the CPW are used for the harmonic suppression. By properly adjusting the coupling slot lengths, the second and third harmonics can be suppressed separately or simultaneously. The principle of harmonic suppression is discussed, and simulation and measurement results are also presented and discussed.