Design and analysis of an R-shaped dual-band planar inverted-F antenna for vehicular applications

A dual-band R-shaped planar inverted-F antenna is proposed for vehicular application. Utilization of this unique geometry dual-frequency operation is achieved with a single feed. The proposed antenna operates in the 225- and 450-MHz bands. Input impedance and return loss data as function of various antenna parameters are,presented, which show that parameters can be adjusted in order to obtain optimum tuning. Radiation pattern data for the antenna mounted on the roof of two types of vehicles are given. The pattern in the low-frequency band is essentially omnidirectional while that in the high-frequency band is directional and normal to the antenna surface. With proper scaling, this antenna may be suitable for dual-band GSM 900/1800-MHz phone applications.