Omnidirectional Cylindrical Microstrip Antennas with Horizontally-Polarized Radiation

A cylindrical microsrip antenna (CMA) is a good platform to get an omnidirectional radiation pattern. In literature some designs on such a platform have been presented, but mainly for the vertical polarization, when the electrical field vector lies in the plane of the cylinder axis. This paper presents two designs of CMA with horizontally-polarized radiation. The first one involves one probe-fed active and two passive cylindrical strips. The resonances are carefully studied and the working frequency, revealing a shift towards higher frequencies. The second design is based on two pairs of strongly coupled E-shaped patches. This type of CMA has not been studied yet. To get an extended bandwidth a textile substrate with low permittivity has been used. In both cases an omnidirectional pattern in the horizontal plane has been obtained. In the second design a 12.5 % bandwidth has been reached.