| Combinatorial Non-periodic Defected Ground Structure (CNPDGS) is development from EBG structure. It is capable of prohibiting the propagation of electromagnetic waves within a certain band of frequencies like EBG., and show slow-wave characteristics. The structure of CNPDGS is entirely different from the structure of periodic EBG. Compared with periodic EBG, the structure of the CNPDGS is simpler in structure, smaller in dimension and lower in insertion loss. These characteristics allow wide application in restraining the surface radiation of antenna, enhancing the output power of amplifier and oscillator, constructing high impedance microstrip, reducing the size of circuit etc.Finite-Difference Time-Domain (FDTD) method is a direct time domain method for solving Maxwell equitation. It can be used to determine the amount of the scatter and the radiation of complex or un-uniform object. In this paper, the FDTD method is programmed with the blend of C and Matlab languages, which combines the merits of the two languages. With the help of this powerful electromagnetic simulation programme, we study the characteristic of CNPDGS and bring out a new CNPDGS. Parameters of the model are extracted from the EM simulation results.Advanced Design System designed by the Agilent company, America, is a powerful electronic design automation software system. It offers complete design integration to designers of products such as RF \MW circuits, wireless networks, RFIC and communications systems. In this paper two amplifiers are fabricated with ADS,of which one is designed using conventional microstrip line and the other is reduced using CNPDGS. Furthermore the series microstrip lines with CNPDGS are reduced by 27.9% than that of the conventional one.These circuits mentioned above are tested by Network Analyzer. The test results show the good agreements with the simulation. The circuit design using CNPDGS will be an important theory in wireless communication technology in the future. |
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