Simulation And Design Of Scdma/wlan/td-scdma Combiner For Basestation Application

With the rapid development of mobile communication, SCDMA and TD-SCDMA, which both are the independent intellectual property rights technologies of our country, has becoming more and more mature and are stepping into the mobile communication market steadily. In order to reduce the operating cost of the mobile communication network, domestic operators adopt the coexistence scheme of multi-network, which proposes high technical requirement on the compatibility of multiple networks. Multi-frequency combiner is the important device in a multi-network system with a community antenna. It combines and separates different frequency components and the effective design of the combiner is the key issue for achieving the compatibility of multiple networks. In this dissertation, a SCDMA/WLAN/TD-SCDMA combiner is successfully designed for the coexistence of the three networks, and the design and tuning process of this combiner are introduced.A multi-frequency combiner is composed of two or more microwave filters and thus the design theory of microwave filter is introduced firstly. Generalized chebyshev theory and the synthesis procedure are presented. Different optimization methods, such as rotation, Newton-Raphson and Particle swarm are utilized to simplify the coupling matrix for some common microwave filter structures. Especially, the Particle swarm optimization method is proved to be very effective.Then, the design of the SCDMA/WLAN/TD-SCDMA combiner is introduced. The coaxial cavity is adopted for achieving better technical indexes, such as high rectangular coefficient and high power capacity. The combiner is designed and optimized by using Ansoft HFSS and designer, and after several times of optimization, the interference between different channels has been largely reduced. The designed combiner is fabricated and further measured by the use of Agilent network analyzer, and the measurement results meets quite well with the desired indexes.At last, for the industrialization of this combiner, a fast manual tuning scheme is proposed to improve the tuning efficiency. Further more, some problems on the computer aided automated tuning technology are also discussed for the next step investigation.