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Radar cross section (RCS) of conformai antenna integrated into the aircraft surface cannot be measured by general RCS measurement method. A new method is presented in this paper in order to achieve accurate RCS of conformal antenna. RCS of conformal antenna is obtained by spatial spectral transforming and scaling of two-dimension (2-D) microwave imaging. Empirical results also show the proposed method...
Measurement precision of Low frequency antenna is poor for the apparent reflection from absorbers in anechoic chamber. According time-frequency transform theory, a certain bandwidth signal holds the ability of certain range resolution, so a time-domain antenna measurement model can be built. Based on real frequency bandwidth, extrapolating the frequency band to lower frequency and higher frequency...
VHF / UHF band antenna measurement is easily influenced by surroundings. Since the bandwidth of antenna is narrow, the corresponding time-domain resolution is low, so it is difficult to eliminate the effect of multipath signals by adding a time domain gating. This paper presents a method which uses the return loss of antennas to compensate the spectrum of signals. The method extends the test bandwidth...
A hard-in-loop polarization Synthetic Aperture Radar (SAR) system was constructed in an anechoic chamber. The operation track of SAR was simulated by lateral movement of a scanner. As the core hardware of system, a vector network analyzer was set in the scanner and moved together. Two measured channels were connected with four vertical or horizontal antennas by the expand ports. Then the full-polarization...
Comparing with traditional way of continue-wave RCS measurement system, high-resolution information is gained in stepped-frequency system. Using inverse fast Fourier transform, the frequency-domain data of the whole chamber obtained by testing is interpreted into high-resolution time-domain response, and the unwanted signals can be removed by adding a gating function. The measurement of finite frequency...
In order to meet the approximate plane-wave irradiation condition, adequate large field or compact range system is needed for antenna pattern measurement, especially for large size antenna, but an outside testing field site or a compact range system is very expensive. Near-field planar scanning system is another method, however it is time-consuming and only suited for directional antenna. In this...
In the case of multi-objective detection, the received signals by radar are the vector superposition of each scattering point. High resolution imaging is a method to distinguish the location of multi-objective. Many algorithms are used for different wideband signal. In this paper, convolution back-projection (CBP) algorithm based on stepped-frequency signal is employed to process the echoes received...
In order to meet the approximate plane-wave irradiating condition, adequate large field or compact range system is needed for RCS measurement of large aircraft targets. However, an outside testing field site or a compact range system is very expensive, so a new RCS extrapolation method named Hankel algorithm based on near-distance testing has been presented. According to the fact that objective reflectivity...
Traditionally, the time-gating method (TGM) is helpful in improvement of ordinary antenna pattern measurement. But for a low frequency antenna under test (AUT), especially a narrow bandwidth AUT, even inside an anechoic chamber, the improvement may be very limited. This paper presents a method of bandwidth expanding for a FD measuring system, which can realize TGM with its fast frequency sweep function...
In general, RCS measurement must meet the far-field condition, which need a vast measuring area or a costly compact range. To solve the problem, a new technique by extrapolation correction dealing with near-distance RCS measurement of aircraft targets is set up. The RCS of aircraft target under spherical wave illuminating can be adopted to extrapolate far-field RCS of them. The convolution arithmetic...
In this paper, two 3-D (three-dimensional) imaging techniques, MB-TomoSAR (multi-baseline SAR tomography) and CSAR (circular synthetic aperture radar), are introduced firstly. Secondly, the indoor experimental systems for acquiring SAR data in the microwave anechoic chamber are described, then the experiments of the two 3-D imaging mode for the metallic spheres and human body are performed, respectively...
Radio frequency simulation systems (RFSS) are widely applied in the radio seeker research, but in low band (1-2GHz), the position precision of radio frequency array as a key parameter is hard to insure by hardware ways, and often hard to meet the experimental requirement. One new method by software calibration is put forward. By analyzing the position errors of array systematically, errors are decomposed...
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