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Session: TU3B1:20 PM Tuesday, June 17, 2008 Room: A312 |
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Session: TU3B | RF MEMS Device Technology |
Chair: | Dan Hyman, XCom Wireless |
Co-Chair: | J. Robert Reid, Air Force Research Lab |
Abstract: | As RF MEMS switches continue to mature new and interesting device types and measurements emerge. |
| | TU3B-01 | A SP2T and a SP4T Switch using Low Loss Piezoelectric MEMS | 1562 | D. J. Chung1, R. G. Polcawich2, D. Judy2, J. Pulskamp2, J. Papapolymerou1, 1Georgia Institute of Technology, Atlanta, United States, 2US Army Research Laboratory, Adelphi, United States |
| This paper presents Single Pole Double Throw (SP2T) and Single Pole Four Throw (SP4T) switches using piezoelectric micro-electro-mechanical (MEMS) switches measured from DC to 50 GHz. The overall performance of the switches shows better than 20 dB isolation up to 50 GHz when the MEMS switches are in the off or zero volt state. When the switches are actuated with 7 V, the SP2T shows less than 1.8 dB of insertion loss while the SP4T shows less than 2 dB of insertion loss, on average, up to 40 GHz. In addition, an undercut in the device is introduced in the junction region of the switches to allow for increased power handling and the response shows negligible change compared to the original switch design. | | |
TU3B-02 | Stable Multi-Step Capacitance Control with Binary Voltage Operation at +/-3V in Integrated Piezoelectric RF MEMS Tunable Capacitors | 1388 | T. Nagano1, M. Nishigaki1, T. Kawakubo2, K. Itaya1, 1Toshiba Corporation, Kawasaki, Japan, 2Toshiba Research Consulting Corporation, Kawasaki, Japan |
| The design and operation technique for a stable capacitance control in piezoelectric RF MEMS tunable capacitors have been investigated. Four folded-beam capacitors composed of piezoelectric aluminum nitride thin films were integrated in the quadruple capacitor and each folded-beam capacitor showed uniform operation voltage of less than 3V. A stable multi-step capacitance control was realized with the binary voltage operation at +/-3V, where each capacitor could be handled at binary state of capacitance due to its saturation characteristics. Eight levels of capacitance value up to 1.5pF with a step of 0.13pF to 0.16pF were realized. | | |
TU3B-03 | Microwave Intermodulation Technique for Monitoring the Mechanical Stress in RF MEMS Capacitive Switches | 1182 | C. Palego1, S. Hadler1, B. Baloglu1, Z. Peng1, J. C. Hwang1, H. F. Nied1, D. I. Forehand2, C. L. Goldsmith2, 1Lehigh University, Bethlehem, United States, 2MEMtronics Corporation, Plano, United States |
| For the first time, a microwave intermodulation technique is used to measure the mechanical resonance directly on packaged and unpackaged RF MEMS capacitive switches with quality factors approaching unity due to air damping. The result is validated by similar measurements in vacuum with much higher quality factors. From the measured resonance frequencies, the residual mechanical stress of the fixed-fixed membrane of the switches is derived and its temperature dependence is analyzed and correlated with that of the pull-in voltage. The present technique offers a convenient means for monitoring the residual stress in RF MEMS devices in both manufacturing and operation. It also allows mechanical and electrical degradation effects to be conveniently separated during life testing of the switches. | | |
TU3B-04 | Study of Residual Charging in Dielectric Less Capacitive MEMS Switches | 1492 | D. Mardivirin, D. Bouyge, A. Crunteanu, A. Pothier, P. Blondy, Xlim - Umr Cnrs 6172, Limoges, France |
| Dielectric charging is one of the most challenging issues in RF-MEMS capacitive switches. A dielectric less capacitive switch is tested with a measured on to off ratio of 9. The reliability of the switch has been studied and residual pull in voltage shift has been observed. For the first time, charging results are presented and modeled on this type of switch. It is shown that charging can be modeled using a simple Curie-Von Schweidler equation. This model has been validated, with good agreement between the coefficients determined after holding down the switch for about 16 minutes, and further experimental results up to one month in the down state. | | |
TU3B-05 | A 2-Pole Digitally Tunable Filter Using Local One Bit varactors | 1479 | M. Houssini, A. Pothier, A. Crunteanu, P. Blondy, Xlim - Umr Cnrs 6172, Limoges, France |
| This paper presents the design of tunable filters based on capacitive RF MEMS switched loads appropriately distributed along an hairpin resonator. The capacitive load distribution is computed using hybrid circuit EM simulation and allows precise computation of the frequency shift for every location of the switched load. To prove the concept, a two pole filter has been fabricated on a 525 µm-thick quartz substrate and it occupies a total area of 1x0.85 cm2. Its center frequency can be discretely tuned using 2 capacitive switches from 9.8 to 11 GHz with 4 positions. Return losses less than 15 dB and insertion losses better than 2.5 dB have been measured over the whole operation band. | | |
TU3B-06 | MEMS Liquid Metal Through-wafer Microstrip to Microstrip Transition | 1750 | X. Liu1, L. P. Katehi2, D. Peroulis1, 1Purdue University, West Lafayette, United States, 2University of Illinois, Urbana Champaign, Champaign, United States |
| A novel approach for creating an RF MEMS switch in the form of a microstrip-to-microstrip liquid-metal transition is presented. A slug of non-toxic liquid metal that controllably fills a through-wafer via is the key component of the switch. The large contact area between this slug and the solid microstrip lines renders this design an excellent candidate for high-power switching and particularly for hot-switching applications. With the slug inside the via the switch presents a measured insertion loss of 0.24 and 1.1 dB up to 5 and 10 GHz respectively. When the slug is removed from the via the switch isolation is measured to more than 20 dB up to 7 GHz. The fabrication technology and critical trade-offs between RF and microfluidic performances are discussed in the paper. The slug movement is controlled by an external micropump. The recent advances in microfluidics have resulted in a large variety of practical micropumps that may be monolithically integrated with such switching designs. | | |
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