Microwave Multiplexing Coupler Technology

In some applications of wireless communication, it is demanded that the radios within the same operation band have to work simultaneously, which have brought harmful EMC problems. By fully usage of the antenna, the multicoupler can solve the EMC problem and improve the communication quality. Multicoupler play important roles in communication system. Emerging wireless communication applications continue to challenge multicoupler with ever more stringent requirements: more-coupling channels, higher performance, smaller size and lighter weight.In the frequency range of UHF, if using the waveguide or the coaxial structure filters, then the size and weight is big; if using lumped element(LC) filters, the Q value is low, the insertion loss is high, although the size of the filter is small; but the helix filter are precisely situated between these two kinds of filters, the Q value can achieve above 1200, insertion loss is lower than the LC filters; moreover the size of the helix filter are small and can realize narrow bandwidth, the manufacture is easy and so on.As concerning to a certain EMC problem in the UHF communication, an eight-path multicoupler using helix filter is proposed to solve this problem, which has improved the communication quality.In this paper, introduce the theory and formula of filter design and a brief overview of the principles of operation and the main design considerations for several different multicoupler configurations was introduced, the helix filter is manufactured which works in UHF band. Based on the analysis of the theory and the realization shape, the folded line multicoupler with helix filter is utilized to design the eight-path multicoupler. The whole system is designed, simulated, and manufactured. The measured results indicate the loss of this multicoupler is lower(loss 2dB), more-coupling channels, achieved the design requirements.