A Linear-Scan-Based Wideband Single-Cut Near-Field RCS Measurement Technique With Wide Effective Angle Coverage

Abstract

A linear-scan-based wideband near-field radar cross section (RCS) measurement technique for achieving wide effective-angle-coverage is proposed in this letter. Both the data preprocessing and linear near-field to far-field transformation (LNF2FFT) techniques are used to ensure the accurate measurement of wideband far-field RCS in a wide azimuthal angle range. With the linear-scan-based near-field sampling strategy, the object under test (OUT) keeps stationary during the measurement process, and the equipment of turntable is not required. Moreover, based on the 2D plane wave expansion, LNF2FFT is proposed to translate the linearly sampled near-field data into far-field RCS pattern. An adaptive time gating strategy is also proposed to deal with the varied background property in liner samplings. Serval important practical factors relating to the measurement accuracy, such as phase center calibration, background subtraction and calibration, are also discussed in detail. Two illustrative test examples are presented, in which RCS measurement with wide effective-angle-coverage of ±35° and the average wideband measurement errors less than 0.4 dB are achieved in 1 m limited measurement range.