DocumentCode :
2966333
Title :
Coplanar-waveguide embedded mechanically-bistable DC-to-RF MEMS switches
Author :
Sterner, Mikael ; Roxhed, Niclas ; Stemme, Göran ; Oberhammer, Joachim
Author_Institution :
KTH - Inst. of Technol., Stockholm
fYear :
2007
fDate :
3-8 June 2007
Firstpage :
359
Lastpage :
362
Abstract :
This paper reports on a novel electrostatically actuated, mechanically bi-stable metal-contact MEMS switch suitable for switching signals from DC to microwave frequencies. In contrast to conventional RF MEMS switches whose actuator is typically built on-top of the transmission lines, the switch mechanism is completely embedded in the signal line of a low-loss three-dimensional micromachined coplanar waveguide, which results in a minimum transmission line discontinuity. Furthermore, the in-line switch is mechanically bi-stable by an interlocking hook mechanism, i.e. it maintains both its on-state and its off-state without applying external actuation energy. External actuation voltage is only needed for triggering the transition between the two states. Thus, it is a true static zero-power device suitable for extremely low power applications and for applications where the switch configuration must be maintained even at a power failure. As a third major feature, the switch provides with active opening capability which potentially improves the switch reliability and makes the design suitable for soft, low-resistivity contact materials. The switches have been fabricated in a single photolithographical process step together with their three-dimensional coplanar waveguides. Including a 500 mum long 3D micromachined transmission line with less than 0.4 dB/mm loss up to 10 GHz, the total insertion loss was measured to 0.15 and 0.3 dB at 2 and 10 GHz, respectively, and the switch isolation is 45 and 25 dB at 2 and 10 GHz, respectively. The minimum transmission line discontinuity of the switch concept is demonstrated by its insertion loss of less than 0.1 dB up to 20 GHz for the switch mechanism alone, i.e. when corrected by the transmission line loss. The electrostatic actuation voltages for the different switch designs were measured to be between 23 and 39 V.
Keywords :
coplanar waveguide components; electrostatic actuators; micromachining; microswitches; photolithography; transmission lines; 3-D micromachined coplanar waveguide; 3D micromachined transmission line; bi-stable metal-contact MEMS switch; conventional RF MEMS switches; electrostatic actuation voltage measurement; external actuation energy; external actuation voltage; frequency 10 GHz; frequency 2 GHz; in-line switch; interlocking hook mechanism; loss 0.15 dB; loss 0.3 dB; low-resistivity contact materials; mechanically-bistable DC-to-RF MEMS switches; novel electrostatically actuated switch; single photolithographical process; size 500 mum; static zero-power device; switch fabrication; switch reliability; switching signals; total insertion loss measurement; transmission line discontinuity; voltage 23 V to 39 V; Coplanar transmission lines; Coplanar waveguides; Insertion loss; Microswitches; Power transmission lines; Propagation losses; Switches; Transmission line discontinuities; Transmission line measurements; Voltage; 3D transmission line; MEMS switch; RF MEMS; microrelay;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Microwave Symposium, 2007. IEEE/MTT-S International
Conference_Location :
Honolulu, HI
ISSN :
0149-645X
Print_ISBN :
1-4244-0688-9
Electronic_ISBN :
0149-645X
Type :
conf
DOI :
10.1109/MWSYM.2007.380445
Filename :
4263822
Link To Document :
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