DESIGN AND DEVELOPMENT OF DGS BASED MICROSTRIP FILTER FOR ISM BAND APPLICATIONS
Kavitha.M 1, Dr. Prithivirajan.V 2
1 PG student, Department of ECE, National Engineering College, Kovilpatti, Tamil Nadu, .India.
2 Assistant Professor (SG), Dept of ECE, National Engineering College, Kovilpatti, Tamil Nadu, .India.
The Microwave filter plays an important role in most RF/Microwave applications like radar, military, satellite systems. RF/Microwave filters can also be implemented using planar transmission lines such as coplanar waveguide, micro-strip transmission lines. Micro-strip transmission line based filters has its popularity and widespread use are due to its planar nature, ease of fabrication, easy integration and good mechanical support compared to coplanar waveguide. Demand for the high performance system with small size at low cost and integration with other microwave devices has necessitated the development of a miniaturized filter with reduced loss and increased bandwidth. Miniaturization of filters can be done using two approaches depending on the effect of the material used and the structure. In structure based analysis some important and practical methods have found specific attentions on designing micro-strip transmission line based filters such as Defected Ground Structures (DGS), Defected Micro-strip Structures (DMS) and coupled resonator. This paper presents the exhaustive survey of the major techniques used in the design of microwave filters. Among the mentioned methods, DGS can be used to tune impedance of t-line without disturbing the actual characteristic impedance of the t-line. In a word, Impedance of the micro-strip t-line can be tuned by making the defect in the ground plane of the t-line can give rise to increasing effective capacitance and inductance. In this work, analysis on micro-strip transmission line and filter implementation using DGS structure have been carried out and implemented using Ansys High Frequency Structural Simulator (HFSS) from 0 to 5 GHz frequency range for L to S band applications. The obtained insertion loss (S12) is of -14.21dB and return loss (S11) of -1.77dB has been achieved.
