240 GHZ Polarimetric Compact Range for Scale Model RCS Measurements

摘要

A fully-polarimetric compact radar range operating at 240 GHz has been developed for obtaining Ku-band RCS measurements on 1:16th scale model targets. The transceiver consists of dual fast-switching, stepped, CW X-band synthesizers driving dual X24 transmit multiplier chains and dual X24 local oscillator multiplier chains. The system alternately transmits horizontal (H) and vertical (V) radiation while simultaneously receiving H and V. Software range-gating is used to reject unwanted spurious responses in the compact range. A flat disk and rotating circular dihedral are used for polarimetric as well as RCS calibration. Cross-pol rejection ratios of better than 45 dB are routinely achieved. The compact range reflector consists of a 60' diameter, CNC machined aluminum mirror fed from the side to produce a clean 27' FWHM quiet zone. In this paper a description of this 240 GHz compact range is provided along with an ISAR measurement example.