Wideband, High Gain, Variable Time Delay Techniques for Array Antennas

摘要

The report discusses two improved techniques for obtaining a wideband, high gain, nondispersive, variable time delay device to steer array antennas. The first time delay technique uses two wideband helix structures separated by a cylindrical drift tube to obtain a variable delay of 20 or more nanoseconds with a gain of 20 to 30 db. A variable delay is obtained by controlling the beam velocity through the drift region by varying the drift tube potential. Gain variation is minimized by maintaining constant beam velocity through the helices. The second method is a digital technique in which different time delay elements are switched into the signal path. In this technique, each switch is replaced by a wideband amplifier that determines the system bandwidth (200 to 800 mc). (Author)