On The Multi-Band Base-Station Antenna Elements

In the mobile communication system, the multi-band base-station antennas that a lot of systems share can decrease the number of antennas, reduce the interference among antennas, and save the fabricate cost. They can also share the already existing base-station. Along with the vigorous development of the mobile communication technology, the research of the multi-band antenna element, as the basic component of the multi-band base-station array antenna, is very urgent, which is also of theoretical significance and practical value.First, the reflector in dual-band base-station antenna is designed. The effect of several kinds of reflector on the front to back ratio and horizontal plane radiation pattern of base-station antenna is simulated, and the best reflector is obtained, which meets the radiation demands of dual-band base-station antenna. The design of multi-band antenna is then discussed more especially. Characteristics of multi resonances can be easily obtained by placing many parasitic elements near a dipole antenna, and the broad bandwidth can be obtained by serial setting of the parasitic elements, by which a triple-band dipole antenna is designed. Moreover, the dual-band and broad-band series-fed printed dipole antenna consist of two strip dipoles printed on two sides of a dielectric substrate and connected through parallel striplines. Depending on where the antenna is fed and the way the dipoles are connected, an antenna with dual-band and broad-band capability can be designed. The CPW-fed dual-band monopole antenna discussed consists of two parallel monopoles fed by a CPW line. Its impedance bandwidth for the two operating frequencies can be further enhanced by increasing the width of the longer monopole.