DESIGN & IMPLEMENTAION OF STEPPED IMPEDANCE MICROSTRIP LOW PASS FILTER USING ADS & MATLAB

Abstract

In this report a design technique for a Stepped impedance Microstrip Low-pass filters is presented by using Agilent Advanced Design System (ADS) simulations in order to find the optimal design parameters required to arrive at an approximate solution. ADS simulations were used to accurate determine the final design. The experimental results are in good agreement with theoretical values. Most communication system contains an RF front end which performs signal processing with RF filters. Microstrip filters are a low cost means of doing this. Filters play an important role in microwave applications. Microstrip filters play various roles in wireless or mobile communication systems. There is an increasing demand for newer microwave and millimeter-wave systems to meet the emerging telecommunication challenges with respect to size, performance and cost. This report describes the design of low cost and low insertion loss S-band Low Pass Filter (LPF) by using microstrip layout which works at 2.4 GHz for dielectric constant 4.05 value with a substrate thickness 1mm for order N=6. Microstrip technology is used for simplicity and ease of fabrication. The design and simulation are performed using 3D full wave electromagnetic simulator IE3D. We have also developed program code in MATLAB to plot the insertion loss ( 21 S parameter) of the Low pass filter. A stepped impedance low pass microstrip filter has been design, simulated, fabricated and tested using vector network analyser of operating range 5KHz to 20 GHz. The cutoff frequency achieved is lower than the design specification value(2.4GHz).