Stub- and Capacitor-Loaded Folded Dipole Antenna for Digital Terrestrial TV Reception

A bandwidth enhancement method for a folded dipole antenna is proposed for digital terrestrial television (TV) reception. The antenna has a pair of stubs inside a folded dipole and a capacitor loaded on the folded dipole. A cylindrical wire model with a lumped element capacitor is analyzed by the commercial simulator ldquoFEKO.rdquo The analysis shows the effect of the stubs and capacitor on bandwidth enhancement, using current distributions and a comparison of dipoles without stubs and/or capacitor. A prototype antenna printed on polyethylene terephthalate (PET) film has dimensions of 15 mm by 280 mm with a line width of 1 mm. The capacitor is implemented with a slit on the line for ease of fabrication. The antenna in free space exhibits a voltage standing wave ratio (VSWR) of less than 2.6, and figure-of-eight radiation patterns with gain from 0.7 to 2.5 dBi in a frequency range from 470 to 950 MHz. The antenna attached to flat dielectric plates of materials that are typically used in automotive body parts, maintains a VSWR of less than 2.7 from 470 to 710 MHz for digital terrestrial TV reception.