New design and technologies for broadband crystal video front end

A new crystal video front end design is described, with attention given to technological aspects. It is designed to be used in a four-antenna radar warning receiver spanning the frequency range from the E to the J band and having direction finding capabilities. Experimental results on development and preproduction units are presented. A 90 deg beamwidth spiral antenna covering the entire frequency range feeds a multiplexer that in turn splits the input spectrum into three separate bands. Multifunctional RF modules are connected to the multiplexer output ports, each of which (1) injects test signals into the line, (2) protects the detector diode against incidental high level emissions, (3) handles and blanks CW signals, and (4) detects signals.