Editor´s Introduction [Antenna Designer´s Notebook]

The following paper, on the displaced-axis dual reflector (ADE), illustrates a better way of feed scanning. In 1998 in this column [1], I wrote a paper to show that the displaced-axis dual reflector was very sensitive to lateral feed movement. It would not be a good candidate for feed scanning because the gain dropped rapidly, and its pattern became greatly distorted. Figure 1 illustrates an example of the problem, using a reflector similar in size to the one given in the paper below.