APMC2017 – Asia Pacific Microwave Conference

Joachim Oberhammer

Nano and Microsystem department
KTH Royal Institute of Technology
SE-100 44, Stockholm, Sweden


THz MEMS – micromachining enabling new solutions at millimeter and submillimeter-wave frequencies

Since RF MEMS switches appeared more than 20 years ago, micromachining and micromechanics have been receiving large attention for enabling near-ideal microwave devices. MEMS switches and MEMS-switch based circuits have been through different development stages and are currently proving themselves commercially, among others for mobile-phone antenna-tuner switched-capacitor banks. However, micromachining can do much more than “just” two-dimensional MEMS switches for planar transmission-line technology: Three-dimensional, deep-silicon micromachining allows for new microwave devices with unprecedented performance, and has the potential to become an enabling technology for volume-manufacturable, reconfigurable submillimeter-wave and THz systems. This paper provides an overview of 3D silicon micromachining capability and examples of innovative microwave devices and systems up to 2.9 THz is given, including very complex systems such as a 340 GHz 8-pixel imaging radar developed by JPL. Furthermore, recent achievements in 3-D micromachining at KTH for microwave to THz systems are given, including the first MEMS-reconfigurable submillimeter-wave waveguide components, namely a 3.3 bit MEMS phase shifter and a low-insertion loss / high-isolation MEMS waveguide switch operating at 500-750 GHz. A micromachined technology for multi-pole, multi-transmission zero filers is presented, which enables multi-mode resonators with Q factors of 800 at 270 GHz. Furthermore, a very low loss micromachined waveguide technology is shown, having only 0.02 dB/mm loss at 200-300 GHz, which has enabled ultra-low loss waveguide components such as couplers and power combiners/splitters. Highly integrated sub-THz micromachined waveguide systems require auxiliary components such as compact, integrated matched loads for multi-port devices, which will also be introduced at this talk.


Joachim Oberhammer, born in Italy in 1976; M.Sc. EE from Graz University of Technology, Austria, in 2000; Ph.D. from KTH Royal Institute of Technology in Stockholm, Sweden, in 2004. Post-doctoral research fellow at Nanyang Technological University, Singapore, in 2004, and at Kyoto University, Japan, in 2008. Since 2005 leading radio-frequency/microwave/terahertz micro-electromechanical systems research at KTH; Associate Professor at KTH in 2010; Professor in Microwave and THz Microsystems at KTH since 2015. Guest researcher at Nanyang Technological University, Singapore, in 2007; guest researcher at NASA-Jet Propulsion Laboratory, USA, in 2014.

He is author and co-author of more than 100 reviewed research papers and holds 4 patents. In 2004, 2007, and 2008 he got an award by the Ericsson Research Foundation, a grant by the Swedish Innovation Bridge, and a scholarship by the Japanese Society for the Promotion of Science, respectively. The research work he is heading received six Best Paper Awards (five of which at IEEE conferences), and four IEEE Graduate Fellowship Awards (by MTT-S and by AP-S) since 2009. He served as TPRC member of IEEE Transducers 2009 and 2015, IEEE International Microwave Symposiums 2010-2016, IEEE Micro Electro Mechanical Systems 2011 and 2012, and IEEE Radio and Wireless Week 2015 and 2016. Dr Oberhammer is Steering Group member of the IEEE MTT-S and AP-S Chapers Sweden since 2009. In 2013, he received an ERC Consolidator Grant by the European Research Council. Since 2014 he is Steering Group Member of the Young Academy of Sweden. Since 2016 he is member of the General Assembly of the European Microwave Association.