Design Of Compact Wideband Microstrip Filter For Phased Array Radar Applications

This paper talks about the investigation of three sorts of microstrip line filters (a) coupled line, (b) hairpin and (c) interdigital filters operating for X-band to achieve the best results according to the specifications with minimum size considerations. The designed filters are seventh order Chebyshev filters centered at 9.5GHz, having a fractional bandwidth of 31.6%. ADS (Advanced Design System) software is used to simulate the designs using Rogers RT/Duroid 6010 substrate. The simulated results for all three filters show a good agreement with the specifications having an insertion loss of less than 1dB and return loss better than 10dB. The out of band rejection achieved is better than 20dB at 7.5 and 11.5GHz. However comparative analysis shows that the best performance and compact design is achieved using interdigital filter having a practical application value in phased array radars and communications systems.