High Performances Micro-Machined Millimeter-Wave Structures

In this paper, we present technological (LIGA U.V) and design improvements, through 3D electromagnetic simulations, in a coplanar micro-machined technology on silicon substrate. First, because of the silicon anisotropic etching, we have designed a low loss tapered transition between the 50 ¿ silicon input/output lines and the membrane area. A coplanar micro-machined line, embedded between two tapers and probe pads and featuring an overall insertion loss of less than 0.8 dB at up to 67 GHz has been achieved. From these improvements, we have realised a 30 GHz band pass filter featuring insertion loss of ¿1.6 dB. Finally, we have designed and realised an original cavity resulting from a coupling between coplanar micro-machined lines and a dielectric resonator acting on whispering gallery modes. The results report on high quality factor (QL) of 2400 at 35 GHz.