Ultra Wideband Seven Poles Lowpass Filter Using DGS Array

This project is intended to build a microstrip low pass filter with a pass band till 3 GHz at 3 dB cutoff frequency. This project is divided into two stages. In the first stage, a conventional seven pole low pass filter using commensurate length 8 / g λ is designed by converting the value of g1 to g7 into unit elements as well as open circuit stubs. In second stage, a method to design low pass filter having a Defect ground structure (DGS) as well as defect microstrip structure is proposed. In this Section, we have studied the square shaped DGS array having the same resonant frequency as compare to conventional seven poles low pass filter and compare the response of DGS array with seven poles low pass filter. It is observed that DGS array have more sharp cutoff frequency, quality factor as well as sharpness factor and occupying area of the proposed DGS is less as compare to the seven poles low pass filter. A seven pole LPF based on DGS array has approximately 85% less length as compared to a conventional seven pole LPF.