Showing papers in "Electronics in 1970"

Holography can help radar find new performance horizons

Abstract: This article describes the advantages of using holographic techniques in radar systems, including side-looking, bistatic, passive, pulse compression and pulse doppler radar. The key to the holographic techniques is that coherent radar is a form of microwave holography. The article explains the situations where coherent radar is most effective and describes the principles behind each of these situations. Coherent radar is explained in the light of both airborne and stationary radar systems employing large synthetic apertures which are necessary for the high gain and resolving power of coherent radar. Holography reduces the limitations of present radar systems because of its unique method of display. Output can be either on photographic plates or, if high speed of output is required, ultrasonic cells can be utilized to provide a diffraction pattern providing the target information. Using holographic methods, the doppler effect in side-looking radars is eliminated. Holography permits synthetic end-file gain to endow small airborne antennae with high forward directivity gain and minimize reflections from the ground. In amplitude pulse compression radar, holography can enhance pulse compression. In C-W bistatic radars, where weak signal returns are lost in noise, holography can provide a large signal-to-noise ratio. Holography can also be used in the processing of pulse doppler radar signals where both the range and range rates of many separate targets must be measured.