Micromachined Microwave Components for Communications and Radar

Summary form only given. Complex passive microwave components at frequencies above around 50 GHz are difficult to build because of their small size and high fabrication tolerances required. Micromachining is one technique which can achieve the desired results, and this paper will describe a new micromachining technique together with the microwave design and experimental tests. The applications considered are car communication and radar systems. A SU8 thick photo resist is used to produce a square coaxial cable filter, the filter design fabrication and experimental results will be given. The cable is made of five metal coated layers of SU8 bonded together to form a single component, the SU8 has the advantage that it can form mechanical components up to many hundreds of microns thick whilst still retaining very accurate control over the size of the features. The use of SU8 in this manner eliminates radiation loss and dielectric loss and optimize the conductor loss of the passive circuits; it is therefore useful when the ultimate performance of passive circuits is required.