This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Improved fast switching of radiofrequency (r.f.) energy via PIN-diode switches is essential for receiver protection and deadtime reduction in the design of ACERT next-generation pulsed-ESR spectrometers. Fabrication of a novel, specialized electronic driver for PIN switches has previously been accomplished within the Freed Research Group (U.S. patent #5,214,315). A unique feature of this invention is that it optimizes transition speed under reactive loading conditions typical of Si and GaAs PIN-diode arrays. We are currently upgrading the driver by modeling and specifying higher-performance power MOSFET semiconductors and reformatting the switch driver as a high-performance hybrid circuit. Integration of the discrete components comprising the switch driver onto a compact ceramic substrate will significantly improve switching speed by minimizing parasitic inductance associated with the circuit interconnects. We are employing advanced commercial software tools in order to accurately model the higher-order interconnect parasitics and semiconductor characteristics; this capability allows efficient simulation and selection of newer semiconductors best-suited to this application. It also permits accurately predicting the magnitude and effect of minute parasitic reactances, greatly reducing the time required for convergence of layout variations. Simulation studies indicate that the most recent hybrid driver design should perform at the 6 - 8 ns level for charge transfers of 15-20 nC. This figure translates to probable r.f. switching speeds in the 10 - 14 ns range for high-power silicon PIN diode arrays, or 4 - 6 ns for h.v. GaAs PIN arrays. The driver hybrid assembly is physically small and can therefore be situated in close proximity to its associated PIN arrays, minimizing detrimental transmission-line effects and electromagnetic interference. We are evaluating further candidate PIN devices and plan to requisiton the hybrid drivers once the PIN diodes have been characterized in the context of our ongoing microwave spectrometer development.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
2P41RR016292-06
Application #
7420443
Study Section
Special Emphasis Panel (ZRG1-BCMB-K (40))
Project Start
2006-09-15
Project End
2007-08-31
Budget Start
2006-09-15
Budget End
2007-08-31
Support Year
6
Fiscal Year
2006
Total Cost
$17,433
Indirect Cost
Name
Cornell University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
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