Prediction of Low Sidelobe Antenna Performance in the Presence of Large Scatterers Using RF Field Probe Techniques
WESTINGHOUSE DEFENSE AND ELECTRONICS CENTER BALTIMORE MD SYSTEMS DEVELOPMENT DIV
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Modern airborne radar systems that demand narrow beamwidths and low sidelobes require large antenna apertures. As the antennas become larger and sidelobe requirements tighter, the effects of scattering from the aircraft structure becomes more pronounced and the resulting antenna performance can become quite degraded. It would therefore be useful to know beforehand what affect the aircraft will have on the performance of the antenna. A brute force method of obtaining this information would be to build and mount a full scale antenna on the plane, but this would be quite expensive due to the high cost of fabricating the antenna. This paper presents a more practical measurement scheme using a full scale model of the plan and a field probe assembly. The field probe track assembly is mounted on the aircraft in the same location as the proposed radar antenna. With a RF signal source in the far field, the field probe is moved over the whole area of the antenna aperture and data is taken at each point corresponding to a radiating element location. These complex data points are then processed along with the theoretical antenna aperture distribution to obtain a predicted actual antenna pattern in the presence of the aircraft.
- Electrical and Electronic Equipment