Microstrip filters are always preferred over lumped filters at higher frequencies and today they are integral part of almost all RF and wireless applications. Hence design and development of superior and cost effective microstrip filters of miniature size has become an active research area, especially with the help of computer aided design tools. This book contains several conventional designs of microstrip filters having different frequency characteristics. A technique, originally applied to model complex objects called 'Fractals', implemented on conventional microstrip filters for improved responses. This book also contains analysis of photonic band gap technique which has a property of preventing signals from propagating in certain frequency bands. PBG technique has been successfully applied to microwave planar filters for generating stop bands as desired, by etching periodic lattices in the ground plane. There is also description of left- handed media which V.G.Veselago proposed in 1968 and its possible implementation. A novel contour integral approach has been demonstrated which can be conveniently applied to microwave planar circuits of arbitrary shapes.