This thesis investigates a new transmission lines technologie called "Substrat Integrated Waveguide (SIW). SIW takes advantages of rectangular waveguides and microstrip transmission lines, to be used in the construction of low loss microwave circuits. At the beginning of this work, some well known technologies of transmission lines (like microstrip line, rectangular waveguide .... etc.) were studied, to recognize the advantages and disadvantages of each technology, and the applications that could be built by them. Then the structure of the substrate integrated waveguide technology was presented, and the possible propagation modes were studied. In addition, the aproximate equations used in its design were given. After that, a comparison between SIW and rectangular waveguide was done. Interconnections between SIW and other transmission lines (like microstrip line, rectangular waveguide .... etc.) were also studied, to define the structure that gives the lowest possible insertion loss and the widest passband. Finally, we reviewed the important role played by filters in the fields of cellular communications, radar, electronic warfare and satellite systems.