Citation
Abstract
High-fidelity electromagnetic modeling of the performance of low-gain communications antennas on complex spacecraft (including low orbiters, landers, and rovers) has been needed for decades, as evidenced by the requirement for at least a 10-dB margin on all links using low-frequency omni-directional antennas. A difficult area is prediction of performance of low-frequency in situ links. The prediction difficulty stems from the interaction of the antenna with other structures onboard the spacecraft and from the effects of planetary terrain; both of these phenomena can be assessed only by means of detailed computational electromagnetic (CEM) analysis. Experimental methods used in the past are limited and require massive computer hardware. CEM has only recently advanced to the point where accurate prediction of in situ low-gain antenna performance is possible. This article describes an effort that was aimed at establishing such a capability. It describes the progress made toward developing design methods and philosophies that projects can use to minimize the effects of in situ link multipath and onboard electromagnetic interference. Although continual improvement of this CEM capability is intended, the tasks accomplished so far have created a basis that will serve the projects for the next decade, a basis that includes these initial tools, the knowledge to use them, and the validation data indicating their attainable accuracy. It appears that, as a result of this work, the long established 10-dB margin can be significantly reduced, possibly by as much as 6 dB.
Keywords
Details
- Volume
- 42-170
- Published
- August 15, 2007
- Pages
- 1–18
- File Size
- 1.9 MB