A SIMPLE APPROACH FOR DESIGNING A FILTER ON MICROSTRIP LINES

This paper deals with the design and fabrication of edge-coupled band pass filter (BPF) circuit (fifth order) on microwave laminate for 4.5 GHz ± 0.5 GHz application. The design of filter is realized on a high quality RT/ duroid laminate having the dielectric constant 10.5 and substrate thickness 1.27 mm. The relevant design specifications, simulation, and test results of the circuit is described. The numerical calculations and simulations are performed in Linpar. The Printed Circuit Board (PCB) artwork is prepared in CorelDraw. A prototype of the design was manufactured and tested on microwave network analyzer. Some offsets are observed between the theoretical and practical results, which may be attributed to the wide tolerance in the dielectric permittivity specified for the RT/ duroid substrate.