THE METOD OF SYNTHESIS OF QUASI-DUAL-BAND MATCHING DEVICE

Abstract

The article presents some findings on the potential of analytical methods for the synthesis of broadband matching circuits for solving nontrivial circuit engeneering problems. Nontriviality shows itself in the technique for the assignment of the frequency response model (approximation) for the broadband synthesis in cellular communication, when double-band antennas are essential. The frequency response model appears as the result of frequency transformation, which yields in the assignment of both bands at the very first stage of the synthesis. The bands’width and isolation between them may be controlled independently, which is the essential part of the frequency transformation. Such way offrequency response assignment allows the potential of the method, which is always restricted by a load, to find broader application. In these conditions the frequency response turns to a quasi-double and asymmetrical one due to finite isolation between bands. We also present the general approach to the synthesis, which incorporates both the frequency transformation and novel synthesis technique. The modified frequency transformation can be applied to all types oftraditional approximations of arbitrary orders in synthesizing broadband frequency-selective matching devices. The distinctive feature of this technique is in the use of generalized Darlington’s synthesis for solving the problems of broadband matching of resistances in a lumped element basis with the application of frequency reponses obtained through modified frequency transformation. We have also estimated the efficiency of the developed technique by comparison with the known results.