A Lower-Profile Top-Loaded Antenna for Automotive Application

This letter presents a lower-profile top-loaded automotive antenna which can be placed inside a shark-fin plastic cover. The antenna is combined with a dual band antenna and GPS antenna. The dual band antenna is composed of two cross print patches with four shorting pins and top-loaded disk. The print patches is composed of two triangular patches which service from 800 to 970 MHz and two parasitic patches which contribute to the band of 2.35-2.62 GHz. The shorting pins are introduced to reduce the height of the antenna. The antenna has omnidirectional radiation patterns in both operation bands. The height of the proposed antenna prototype is only 0.08 λ0 ( λ0 is the wavelength of the lowest frequency in the free space) while the gain in lower band is 4.3dB by optimization of the gaps etched on the patches. The antenna has been fabricated. The simulated and the measured results display very good agreement.