|Acquisition Program: ||TBD|
| ||RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is “ITAR Restricted”. The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the “Permanent Resident Card”, or are designated as “Protected Individuals” as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.|| Objective: ||Develop a physics-based simulation tool that incorporates sophisticated coupling models as well as transmitter and receiver models for predicting EMI among multiple radio frequency (RF) systems on an airborne platform.
|| Description: ||It is not unusual for modern aircraft to utilize over one hundred antennas systems. These systems often interfere with one another thus requiring elaborate frequency management schemes. Advanced full-wave and asymptotic solvers exist for predicting coupling between antennas located on a common platform. These tools can very accurately predict the power received at a receiving antenna due to a transmitting antenna. Test engineers, however, often need to predict the fre-quency and level of the signal that will be seen at the intermediate frequency (IF) filter of the receiver. A strong signal seen at the antenna port of the receiver does not necessarily equate to an interference problem. Additionally, low level out-of-band signals can produce interference through intermodulation products generated in the mixer of the receiver that pass through the IF filter and disrupt the performance of the system. A tool is required that allows analysts to accurately predict RF system level performance with respect to EMI and to mitigate any problems discovered during the analysis process. The resulting tool should employ advanced computational solvers for both full-wave and asymptotic regimes to compute coupling between antennas across a very large frequency range (2MHz – 40GHz). Models for transmitter emissions and receiver response should be developed. The user should be able to specify transmitter and receiver charac-teristics through very simple (e.g., piecewise linear descriptions) or more complex (e.g., circuit level) models to facilitate various types of users, from novice to expert. Additionally, the tool should incorporate visualization capabilities that assist the user in problem setup, analysis, and post processing of results.
|| ||PHASE I: Demonstrate proof of concept prototype algorithms for simple transmitter/receiver models and identify full-wave and asymptotic solvers for the coupling component of the analysis tool. Develop a plan for integrating the coupling and transmitter/receiver models into a single tool as well as layout a graphical user interface (GUI) for this tool.
|| ||PHASE II: Develop and implement circuit level transmitter/receiver models. Perform integration of solvers and transmitter/receiver models. Design and implement GUI.
|| ||PHASE III: Conduct EMI/electromagnectic compatibility (EMC) analyses and measurements to assess the actual performance of antenna systems on board actual airborne vehicles in support of existing and future programs. Develop commercial strength version of tool.
PRIVATE SECTOR COMMERCIAL POTENTIAL/|| ||DUAL-USE APPLICATIONS: The EMI problems encountered on military aircraft are also a serious problem for commercial airliners. Commercial aircraft manufacturers currently use very crude codes (e.g. spreadsheets) or "back of the envelope" calculations to study EMI problems associated with antenna to antenna coupling. A sophisticated tool such as the one proposed would allow for much greater accuracy and efficiency in this process, which will in turn provide significant time and cost savings.
|| References: ||1. Kodali, W.P., Electromagnetic Compatibility. New York: Wiley-IEEE, 2001.
2. Paul, C.R., Introduction to Electromagnetic Compatibility. Hoboken: Wiley-Interscience, 2006.
3. Weston, D., Electromagnetic Compatibility, 2nd ed. New York: Marcel Dekker, 2001.
|Keywords: ||Broadband Antennas; Phased Arrays; EMI Coupling; Design Parameters; Optimization Algorithms; RF Systems|