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Band-selective interferer rejection for cognitive receiver protection

IEEE MTT-S International Microwave Symposium Digest

Scott, Sean M.; Nordquist, Christopher N.; Leonhardt, Darin L.; Jordan, Tyler S.; Rodenbeck, Christopher T.

The concept for a new, frequency-selective limiting filter is presented. This is accomplished by placing a phase change vanadium dioxide (VO2) film at the proper node of the filter. When the high-powered microwave signal reaches a certain threshold, the VO2 undergoes a phase transition from the monoclinic "insulator state" to the tetragonal "metallic state". This crystallographic change is accompanied by a 3 order of magnitude drop in the film's resistivity, and creates a short circuit at a section of the filter, changing a pole to a zero, and rejecting further undesirable high-powered signals from damaging sensitive receiver components. This paper details the design and simulation of the filter, along with measurement results from VO2 films and the filter element. This filter element begins rejecting at about 2 W input power, with isolation of over 16 dB to over 23 W input power, and is unaffected by an out-of band interferer of over 25 W. The architecture presented allows for filter banks capable of automatically-rejecting interferers, yet allowing signals of interest to pass. © 2013 IEEE.

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Technology for On-Chip Qubit Control with Microfabricated Surface Ion Traps

Highstrete, Clark H.; Sterk, Jonathan D.; Heller, Edwin J.; Maunz, Peter L.; Nordquist, Christopher N.; Stevens, James E.; Tigges, Chris P.; Blain, Matthew G.

Trapped atomic ions are a leading physical system for quantum information processing. However, scalability and operational fidelity remain limiting technical issues often associated with optical qubit control. One promising approach is to develop on-chip microwave electronic control of ion qubits based on the atomic hyperfine interaction. This project developed expertise and capabilities at Sandia toward on-chip electronic qubit control in a scalable architecture. The project developed a foundation of laboratory capabilities, including trapping the 171Yb+ hyperfine ion qubit and developing an experimental microwave coherent control capability. Additionally, the project investigated the integration of microwave device elements with surface ion traps utilizing Sandia’s state-of-the-art MEMS microfabrication processing. This effort culminated in a device design for a multi-purpose ion trap experimental platform for investigating on-chip microwave qubit control, laying the groundwork for further funded R&D to develop on-chip microwave qubit control in an architecture that is suitable to engineering development.

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Flat plate concentrators with large acceptance angle enabled by micro cells and mini lenses: performance evaluation

Cruz-Campa, Jose L.; Anderson, Benjamin J.; Gupta, Vipin P.; Tauke-Pedretti, Anna; Cederberg, Jeffrey G.; Paap, Scott M.; Sanchez, Carlos A.; Nordquist, Christopher N.; Nielson, Gregory N.; Saavedra, Michael P.; Ballance, Mark H.; Nguyen, Janet N.; Alford, Charles A.; Riley, Daniel R.; Okandan, Murat O.; Lentine, Anthony L.; Sweatt, W.C.; Jared, Bradley H.; Resnick, Paul J.; Kratochvil, Jay A.

Abstract not provided.

Power handling and intermodulation distortion of contour-mode AlN MEMS resonators and filters

IEEE MTT-S International Microwave Symposium Digest

Nordquist, Christopher N.; Olsson, Roy H.

We report measurements of the power handling and intermodulation distortion of piezoelectric contour mode resonators and filters operating near 500 MHz. The output power capability scales as the inverse of the motional impedance squared, and the power handling of resonator filter circuits scales with the number of resonators combined in series and parallel. Also, the third-order intercept depends on the measurement tone spacing. Individual AlN resonators with 50 Ω motional impedance demonstrate output power capability of +10 dBm and OIP3 > +20 dBm, while an eight resonator filter demonstrates output power handling of +14 dBm and a OIP3 > +32 dBm. © 2011 IEEE.

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Results 76–100 of 158
Results 76–100 of 158