Lecture of "Silicon-micromachined THz systems - enabling the large-scale exploitation on millimeter and submillimeter-wave frequencies" by Prof. Joachim Oberhammer.

Within the framework of Santander Chairs of Excellence program, this Thursday December 12, 2019 at 10:00, in room 4.2.E02 of Torres Quevedo building in Universidad Carlos III de Madrid Leganés Campus, Prof. Joachim Oberhammer will give a lecture on "Silicon-micromachined THz systems - enabling the large-scale exploitation of millimeter and submillimeter-wave frequencies".

The lecture consists of two parts:

• Part 1: Silicon-micromachined THz systems (duration approx. 60 min)

Current THz systems are predominantly manufactured by CNC milling. Despite the level of precision of CNC milling achieved in recent years, this fabrication method forwaveguide-based THz systems lacks volume manufacturability and is inferior to silicon micromachining, which achieves feature sizes and fabrication reproducibility down tomicrometers, surface roughness down to nanometers which provides extremely low losses, and high-aspect ratio geometries which are impossible to fabricate in any otherfabrication technology. Micromachined micromechanical devices, for instance mobile- phone microphones and inertial sensors, are manufactured to billions of devices per year, at very low cost and unparalleled product uniformity. This webinar gives an overview of state of the art, the capabilities and limitations of silicon micromachining for millimeter and submillimeter-wave frequencies, and gives several examples of recent achievements of very high performance silicon-micromachined waveguide based THz devices and systems, including: a low-loss waveguide technology with 0.02 dB/mm at 330 GHz, with integrated low-loss couplers, power splitters; micromachined high-Q filter examples including multi-pole/multi-transmission-zeros filter examples based on cavity resonators with measured Q-factors of 1600 at 150 GHz and 800 at 450 GHz, enabling the first 1% fractional bandwidth filters at submillimeter-wave frequencies; a silicon-micromachined platform for a point-to-point telecommunication link including a 130-148 GHz antenna diplexer with 1.5 dB insertion loss and 60 dB isolation, and waveguide-integrated SiGe MMICs; very complex, multi-level waveguide devices including a orthomode transducer from 220-330 GHz with less than 0.6 dB insertion loss and cross-polarization of 35-70 dB in this waveguide band; a corporate-fed antenna array with 256 elements at 320 to 400 GHz, with only 0.8 dB insertion loss, achieving 34 dBi gain; a 1024 antenna array at 320- 400 GHz with 38 dBi gain and 1.5 dB insertion loss; a frequency-steering micromachined radar frontend at 220-300 GHz, achieving a 55 degree field of view with a 3.5 to 10 degree HPBW, using an integrated 2.5D quasi-optical reflector and a leaky-wave antenna array, all of the size and thickness of a thumb nail; and MEMS-waveguide switches operating at 140-220 GHz with 0.6 dB insertion loss and 50 dB isolation over the whole band, and even a 500-750 GHz switch with 2.5 dB insertion loss and 18 dB isolation.

• Part 2: Background information: Micromachining processes – an introduction to thetoolbox available in silicon micromachining (duration approx. 30 min)

This part of the lecture provides background information to those who are interested in how micromachining is done: what kind of substrates are used, what fabrication processes are available. This lecture explains in particular photolithograpy, surface and bulk micromachining, chemical and physical deposition, chemical and physical etching, and wafer bonding.

• CV Prof. Joachim Oberhammer