Microwave Module - Decatur Electronics SI-2 Technical Manual

MICROWAVE MODULE

The microwave module of the SI Arcade consists of a turnstile junction, which is coupled to a machined horn
lens antenna. The antenna radiates microwave energy with right-hand circular polarization and is designed to
receive left-hand polarized energy. The antenna returns the Doppler signal, which is coupled to a turnstile.
This provide isolation between the microwave oscillator and receiver section. The receiver section is com-
posed of a high-sensitivity mixer diode that is coupled to receive the Doppler shifted transmitted signal and a
small amount of the microwave energy from the oscillator. The mixer diode produces a low-level output signal
with a frequency shift of approximately 72Hz per mph of the target velocity.
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