engleski

Near Field Measurements of the FPS117 Radar Phase Array and the Design of Self-Oscillating Antennas and Arrays

In the first part of this presentation, some results of the FPS 117 phased array radar testing will be presented. The FPS-117 is a 3-D Lockheed Martin solid-state radar designed to provide long-range accurate aircraft identification and position data for air defense, navigational assistance and tactical control for both close air support and counter air operations. The purpose of the testing was to determine the electromagnetic emissions of the FPS-117 at a range 20-300m for compliance with the Croatian maximum permissible exposure (MPE) limits, which are more restrictive than the international (ICNIRP, FCC, DIN...) ones. The levels of exposure are measured to check if the radar beam performances provide sufficient protection for various segments of the population in the vicinity of the radar sites. A method of predicting and measurement of the phase array radar emission is developed at the University of Zagreb. The theoretical results obtained from the known array geometry and the measurements taken from the FPS 117 radar array antenna indicated that RF exposure within 300 m (in the Fresnel near-field zone) of the radar was significantly below the MPE levels for both occupational and general population environments. The measurements were made under specific ranges and depression levels from the main beam axis. A good correspondence between theoretically predicted and measured emission levels has been found. The second part of this presentation will be dedicated to the R&D in the field of self-oscillating integrated antennas at the University of Zagreb. Several prototypes with single transistor oscillator and two-transistor push-pull oscillator are designed, manufactured and subjected to experimental verification of their characteristics. Rectangular, square and circular microstrip patches are used. The possibility of obtaining linear and circular polarizations is investigated. Integration of several active antennas in mutually injection locked antenna arrays is studied. Power combining and beam scanning capabilities are demonstrated.

phased array antenna; radar; near field; active integrated antenna; antenna; patch antenna; self-oscillating antenna

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