Modelling of Butter worth low pass Stepped Impedance Microstrip line Filter

Abstract

This paper presents the design of a class of highly selective micro strip low pass filters. The proposed structure is considered for Stepped Impedance Low Pass Butterworth filter of order n=3 and n=5 with cut-off frequency 1.2 GHz and passband ripple of 3.01db [1]. The substrate FR4 having a dielectric constant 4.4 is considered for calculating the physical length of the micro strip low pass filter. The designing equation are solved using MATLAB Software and the results are analysed and compared using IE3D Simulator. The microwave filter is a building block that provides frequency selectivity in various microwave application like mobile, radar, satellite communication systems. The simulated results show the insertion loss and return loss of about -6.65 dB & - 55.49dB for N=3 and -7.23dB &-16.01 dB for N=5.Simulation has also been done for VSWR.