Research Areas :: Research Highlights
Research Areas
The DART lab focuses on the following research areas:- High-Q tunable RF/microwave and millimeter-wave devices and systems
- Micro/Nano-ElectroMechanical (M/NEMS) Systems and RF MEMS sensors and actuators: physics, design, fabrication techniques and characterization
- Terahertz (THz) electronics
Research Highlights
Tunable RF/microwave filters are critical components in any reconfigurable RF front-end systems. Previous technologies for making RF tunable filters have achieved remarkable performance in one aspect or another, but have failed to produced tunable filters with high unloaded quality factor (Qu), wide tuning range (more than an octave) and low power consumption simultaneously. In his graduate study, Dr. Liu demonstrated for the first time a MEMS tunable resonator that achieves a wide tuning (1.9-5 GHz, 2.6:1 tuning ratio), high Qu (300-650) and near zero power consumption. The technology is base on highly-loaded evanescent-mode cavity resonator actuated by an electrostatic MEMS actuator. A two-pole very narrowband tunable filter has been demonstrated with this technology and achieves 3.55-2.88 dB insertion loss over 3.04-4.71 GHz for a 0.7% fractional bandwidth.References:
- Xiaoguang Liu, Linda P. B. Katehi, William J. Chappell, and Dimitrios Peroulis, “High-Q Tunable Microwave Cavity Resonators and Filters using SOI-based RF MEMS Tuners,” IEEE/ASME Journal of Microelectromechanical Systems, Vol. 19, No. 4, pp. 774-784, Aug. 2010. DOI: 10.1109/JMEMS.2010.2055544
- Xiaoguang Liu, Linda P. B. Katehi, William J. Chappell, and Dimitrios Peroulis, “A 3.4-6.2 GHz Continuously Tunable Electrostatic MEMS Resonator with Quality Factor of 460-530,” 2009 IEEE MTT-S International Microwave Symposium, Boston, MA, USA, Jun. 2009. DOI: 10.1109/MWSYM.2009.5165905
In order to determine their application space of this technology, its power handling capability must be carefully characterized. Dr. Liu made the first theoretical explanation of the non-linear responses and power handling capability of tunable evanescent-mode resonators and filters. The theory is also valid for other type of electrostatic MEMS enabled tunable resonators/filters and reveals for the first time the impact of electromagnetic resonance on their power handling capabilities.
References:
- Xiaoguang Liu, Linda P. B. Katehi, William J. Chappell, and Dimitrios Peroulis, “Power Handling of High-Q MEMS Tunable Evanescent-mode Resonators and Filters,” the IEEE Transactions on Microwave Theory and Techniques, DOI: 10.1109/TMTT.2011.2176136
- Xiaoguang Liu, Linda P. B. Katehi, William J. Chappell, and Dimitrios Peroulis, “Power Handling Capability of High-Q Evanescent-mode RF MEMS Resonators with Flexible Diaphragm,” 2009 Asia-Pacific Microwave Conference, Singapore, Dec. 2009. DOI: 10.1109/APMC.2009.5385409
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