TARGETS FOR MICROWAVE RADAR NAVIGATION 



859 



Curves for the response patterns of a corner reflector of triangular aperture 

 are shown in Fig. 8. These curves were obtained with a reflector constructed 

 of silver-painted plywood whose aperture was in the form of a 24-inch 

 equilateral triangle. It had been previously determined that, with suitable 

 paints, reflectors of this construction behaved exactly as though they were 

 made of sheet metal. 



Depending upon its angle of arrival, a ray may be reflected by a corner 

 reflector in one of four ways. If the angle is too oblicjue, the ray may not 

 be returned in the direction of the source at all. If the incoming ray is 



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(<. ,000 FEET ■ ^>l 



Fig. 6 — Arrangement of apparatus for measuring effective areas of targets. 



SYMMETRIC AXIS 

 OF CORNER REFLECTOR 



TO 

 RADAR 



Fig. 7 — Coordinate system used in presenting data. 



exactly perpendicular to one of the three reflecting planes, it will be returned 

 to its source after only one reflection. Should the ray arrive in a direction 

 exactly parallel to one of the three planes, it will again be returned in the 

 direction of its source but in this case it is reflected twice as in a dDiedral. 

 This particular mode of reflection is illustrated by the sharp peaks at the 

 extremities of the curv^es in Fig. 8. For all remaining angles of approach the 

 ray will be returned after three reflections in the manner already described. 

 The central regions of the curves represent this type of reflection which is of 

 principal interest in practice. 



