Abstarct: In recent years, the growing use of mobile communication systems to transmit and receive data has necessitated the use of high-capacity communication channels and consequently wider bandwidth. One of the popular frequency bands to meet this need is the millimeter wave, which has recently been the focus of many researchers. In this band, the use of conventional waveguide structures for example microstrip transmission lines and mextallic waveguides face challenges such as high substrate ohmic losses and the complexity to connection of peripheral walls, which Gap waveguide technology has been proposed as a good candidate to design and fabrication of passive microwave devices, recently. This thesis explores a new structure of groove gap waveguide technology called multi-laxyer waveguide that by stacking several thin mextal plates, a multi-laxyer waveguide transmission line, a multi-hole directional coupler and a waveguide slot array antenna has been designed in E band. Also designing of two millimeter wave band pass filters in the frequency range of 71-76 and 81-86 GHz has been investigated that by incorporating them with an H-plane Tee junction, a diplexer with multi-laxyer waveguide technology has been realized. Despite Conventional groove gap waveguide technology uses periodic mextallic pin textures to realize the Electromagnetic Band Gap, in this thesis the proposed structure utilizes circular holes to eliminate the leakage caused by air gap between laxyers. Another advantages of using this method is to reduce manufacturing tolerances, low losses, lightweight and small volume, low cost of implementation and the ability to integrate with other passive and active microwave components.