P. O. Afanasyev, A. P. Mayorov, V. A. Sledkov
Article contains review about low profile omnidirectional antennas having vertical polarization. The new low profile omnidirectional antenna is described. The new antenna has a simple design and smaller than known antennas. The antenna operating at 425 MHz and having VSWR less than 2 through 2% frequency band is developed. The height of the antenna is 7 mm and its horizontal dimensions are 60×25mm only. Antenna has metal screen therefore one can work as in free space so as on a surface of a metal sheet. It was found the Gain of the antenna is very dependant of dielectric permittivity of its substrate. An antenna made on substrate having 2.5 dielectric permittivity almost 5 dB more than the same size antenna made on substrate having 4.3 dielectric permittivity but its resonant frequency is more dependant of a distance between an antenna and a metal sheet.