CAD OF MICROWAVE INTEGRATED ACTIVE-FILTERS BY THE REAL FREQUENCY - COMPUTER-PROGRAM FREELCD

This article presents synthesis and optimization for active and integr ated microwave filters. The method is based on the real frequency theo ry. Gain, bandwidth, VSWR and group delay are the optimized characteri stics. Optimization is done with the J.J. More subroutine which is an improvement of the Levenberg-Marquardt algorithm. These integrated act ive low-pass and bandpass filters are used in the field of telecommuni cations area. Applications are given with one or several FET, several equalizers and attenuation poles which are necessary for broadband fil ters. Theory is favourably extended to distributed domain with transmi ssion lines and stubs. Lowpass and bandpass examples are given up to 1 4 GHz in localised and distributed domains. Responses of filters can h ave asymmetric frequency characteristics. A CAD program has been writt en and named FREELCD. We give the different subroutines and say that F REELCD is useful for microwave integrated active filters.