Design Of GSM/DCS/WLAN Multiplexer And Antenna And Coupler

In recent years,the developments of GSM and DCS mobile communication networks become more and more mature, the requirement for data business is increasing rapidly.However, with the rapid development of urban size,buildings in urban cities become more and more large and complex,and these factors lead a strong attenuation effect on the outdoor signal of mobile communication base station network and cause a poor indoor communication quality of mobile communication network.Therefore,in order to improve the overall communication quality of the communication network, providing good indoor distribution for telecom operators is urgent needed. Meanwhile, because the wireless local area network (WLAN) has flexibility,mobility, convenient installation,and it is easy for network planning and adjustment,fault location and expanding,so it has rapidly developed in recent years.Therefore, when building a new indoor distribution system for GSM,DCS and WLAN network,several kinds of wireless signals are usually required to share a set of indoor distribution system for avoiding redundant construction and saving cost.Indoor distribution system mainly includes: multiplexer,indoor distribution antennas,coupler and so on.Among them,the multiplexer must has the very high isolation between different signals;indoor distribution antenna can cover all these frequency bands of wireless communication systems with high enough gain;coupler needs to satisfy the requirement of broadband.However/there are some technical difficulties to satisfy these requirements.Therefore,the research on the GSM/DCS/WLAN multiplexer,antenna and coupler for indoor distribution system has high theoretical and practical significance.The task of this paper is to design the GSM/DCS/WLAN multiplexer,antenna and coupler applied to indoor distribution system.In this paper/the multiplexer was realized by properly locating resonators with respect to distributed coupling feeding line and the output feeding lines,the harmonic passband of each bandpass filter was effectively suppressed to achieve high isolation. The antenna designed in this paper was based on the dual-band monopole antenna feeding by coplanar waveguide,which was designed by Horng-Dean Chen,a scholar of China Taiwan. Improving the antenna feeding by asymmetric coplanar waveguide, which characteristic impedance is not equal to50Ω,the triple-band antenna covered the GSM,DCS and WLAN was obtained,and then,the higher gain antenna used for the indoor distribute system was designed by the way of forming linear array.In this paper, multi-section asymmetric parallel coupling structure was chose to realize the broadband coupler,the frequency range of the broadband coupler is from0.88GHz to2.5GHz, which covers the bands of GSM, DCS and WLAN.In this paper,the design method of combining the theoretical analysis with optimizing by electromagnetic simulation software was adopted. According to the design results,the multiplexer, antenna and coupler were fabricated and measured.The final measurement results show that all the design targets of the multiplexer,antenna and coupler meet the design requirements.