Low profile wide stop band microstrip filters for wireless communication applications using defected ground structures

In a communication system, there is an increasing demand for newer microwave and millimeterwave systems to meet the emerging telecommunication challenges with respect to size, performance, and cost. Most of the communication system requires an RF front end which performs the signal processing with RF filters. For such RF front ends, microstrip filters are widely used because of low cost and simplicity. Microstrip filters play very important roles in wireless or mobile communication systems. In this paper, suitable shapes of dumbbell type DGS for respective filters have been investigated in order to achieve low insertion loss (less than 2 dB), stop band as high as 21 GHz, high return loss, improved Q-factor, high band width, and low profile (less than 35 sq mm). Such a low profile wide stop band filters will be very much useful in RF front end of any communication system which performs signal processing. The proposed filters have been designed, analyzed, and simulated for comparison purpose. For the design and simulation, ADS simulation tool is used.