Design And Study Of Directional Antennas For 3G Base Station

In this paper, high-gain directional antennas used for WCDMA and CDMA2000 are studied and designed. We mainly use air microstrip antenna and four-dipole antenna as the antenna elements. Directional array antenna which is composed of two antennas is analyzed, simulated and designed.Being the gateway of the radio signals of mobile communication base station and an important part of the base station equipments, the quality of antenna performance directly influences the effect of the coverage and reception of signals. The immediate purpose of 3G is to improve the transmission rate and increase the number of users, so the antenna is being put into a higher level. There are great differences during the design between 3G antenna and the traditional design. It is required that the operation bandwidth of 3G antenna be up to 460MHz and 3G antenna achieve the effect such as dual-polarization, higher gain, port isolation and ideal direction pattern.The 3G base station directional antenna designed in this paper uses air microstrip array to improve the antenna gain, the microstrip reversal feed technique to enhance the port isolation and non-equal interval feeding to optimize the direction pattern of antenna and achieve zero-points cancellation. In this paper, we use the method of full-wave simulation CST with experiments to study and design the antenna. Based on the antenna frequency parameters measured by the vector network analyzer, the comparison on arrays consist of different units has been discussed.Through theoretical analysis, software simulation and actual tests, the antenna designed in this paper has arrived prospective effect. The designed 3G directional antenna are of operation bandwidth of 460MHz and the port isolation is greater than 28dBi, the mean antenna gain is 17.1dBi, the electric down-inclination is 0 to 10°and can be adjusted.The designed 3G directional antenna has suitable structure, satisfactory performance and great practicability for WCDMA and CDMA2000. The method of improving port isolation is a good reference for the study and industrialization of 3G.