A Strongly Miniaturized and Inherently Matched Folded Dipole Antenna for Narrowband Applications

A novel miniaturized printed folded dipole (FD) antenna has been designed for narrowband sensing applications. It is shown that the antenna may be systematically engineered to achieve matching to a practical source impedance at frequencies well below its half-wavelength resonance using series-LC loading and asymmetrical arm widths. This approach is used to design an inherently well-matched antenna that does not require an external matching network and demonstrates approximately 75% miniaturization, excellent coto cross-polarization separation, over 24 dB higher realized gain, and strongly improved radiation efficiency relative to an unloaded FD of the same electrically small size. Experimental validation of a fabricated prototype demonstrates excellent agreement with simulations.