MEMS integrated metamaterial structure having variable resonance for RF applications Derrick Langley, Ronald A. Coutu Jr. Dr., LaVern A. Starman, Dr., Peter J. Collins, Dr., Air Force Institute of Technology, 2950 Hobson Way, Bldg 641, Wright-Patterson AFB OH 45433, Ronald.Coutu@afit.edu ABSTRACT Metamaterial structures for RF applications are becoming essential in the race to reduce the footprint of antenna and components necessary for RF systems. Metamaterials provide a viable option to engineer structures from commonly used materials and processes to reduce the weight and size requirements for systems that normally operate at ¼ wavelength or greater in size for optimal performance. The Split ring resonators (SRR) first developed by Pendry, et al., has proven to be a viable component necessary to create negative index material structures. A fabricated SRR has a specific resonant frequency brought on by its permanent geometry. By incorporating a MEMS electrostatic cantilever with the SRR, an investigation into the ability to vary the resonant frequency of the SRR was completed. This paper reports on the modeling, design, fabrication and testing for this integrated component. Keywords: Metamaterial, Split Ring Resonator, MEMS, Background Metamaterials developed from the original analytical work of Veselago, who in 1968 presented a paper explaining the concept behind “gyrotopic substances possessing both plasma and magnetic properties.[1]” Based on the analytical results he presented, a high degree of research goes into metamaterial structures. A majority of the investigations focus into research of material structures that do not exist in nature. One of the early breakthroughs in metamaterial research came from the work of Pendry, et al, who developed the Split Ring Resonator (SRR) [2]. The SRR design is a solenoid structure with a capacitive gap. The SRR helps tailor the resonant frequency for a planer structure based on the geometry, capacitive gap and materials. Based on these parameters, the SRR reacts to propagating electromagnetic waves based on the resonant frequency of the material and the ability to geometrically define the resonant frequency of the structure. Figure 1 shows two interlacing SRRs that due to the layout and size define the resonant frequency at RF wavelengths. Interlacing the structures helps to enhance the resonance and improves the figure of merit used as a quality factor in design requirements. For this investigation, cantilevers incorporated into the design of the SRR affect the overall resonance of the structure. Using an electrostatic cantilever, the SRR’s resonant frequency shifts allowing a different resonant frequency based on the proximity of the cantilevers. Isolating the tip of cantilevers from the other side of SRR gap is a dielectric layer which serves as a barrier to direct contact between the cantilever tip and SRR eliminating a short circuit of the structure. Combining the SRR and cantilevers allows for a novel tuning of the resonant frequency based on the pull-in activation of the cantilevers. Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the U.S. Government. Proceedings of the SEM Annual Conference June 7-10, 2010 Indianapolis, Indiana USA ©2010 Society for Experimental Mechanics Inc. 115 T. Proulx (ed.), MEMS and Nanotechnology, Volume 2, Conference Proceedings of the Society for Experimental Mechanics Series 2, DOI 10.1007/978-1-4419-8825-6_17, © The Society for Experimental Mechanics, Inc. 2011
RkJQdWJsaXNoZXIy MTMzNzEzMQ==