Ludovic Carpentier

Surface-Micromachined Rectangular Micro-Coaxial Lines for Sub-Millimeter-Wave Applications

This letter describes the design, fabrication and characterization of surface micro-machined micro-coaxial transmission lines. The fabrication process relies on successive deposition of sacrificial polymer layers and metal electroplating. Transmission lines with a cross-section of 88 μm × 42 μm have been fabricated on a fused silica substrate, with various shapes. These lines are very well suited for applications above 50 GHz, where propagation in air minimizes both loss and dispersion. The measured lines have good performances with measured insertion losses of -0.33 dB/mm @ 127 GHz and return loss better than -15 dB.

3D micro-fabricated high-Q 140 GHz filter

This paper introduces a new fabrication process for the realization of cavity resonators and band pass filters, using additive micro fabrication. 3D air-filled structures with a 195 μm thickness are obtained by using successive electroplating. Thanks to this fabrication process, a 140 GHz cavity resonator with an unloaded quality factor of 511 has been fabricated. A four-pole band pass filter at 140 GHz is presented, with a 3.1% bandwidth at −3 dB, and measured 3.7 dB in-band loss. Measurements are in good agreement with HFSS simulations without any post-processing tuning.

Substrate integrated suspended line to air-filled SIW transition for high-performance millimeter-wave multilayer integration

Substrate integrated suspended line (SISL) and air-filled substrate integrated waveguide (AFSIW) technological platforms have been recently reported. They are both of high interest in the design of high-performance integrated millimeter-wave systems based on low-cost multilayer printed circuit board (PCB) technologies. This has been confirmed through simulations and experiments when comparing the insertion loss at Ka-band of the SISL and AFSIW with other conventional transmission lines. To take advantage of both platforms and interconnect SISL and AFSIW structures and circuits, a broadband SISL to AFSIW transition is reported. For demonstration purpose, a back-to-back transition operating over the Ka-band has been designed and fabricated. It achieves a matching of better than −15 dB and an insertion loss of 0.27 ±0.22 dB (0.11 ±0.06 dB for the transition) over the Ka-band.