Search

In the dynamic game between jammers and radars, it is easily affected by the complex electromagnetic environment, resulting in the generation of asymmetric radar information. In this letter, a jamming effect evaluation method for asymmetric radar information is proposed from the perspective of a jammer. An online jamming effect evaluation model is constructed. An improved class-attribute contingency coefficient (ICACC) method is proposed. The feature attribute weight and inconsistency rate are used to constrain the division process of breakpoints, so that the discretization of radar data is more reasonable. At the same time, a basic belief assignment (BBA) correction method that combines probability similarity for asymmetric information is proposed. The output results of the support vector machine (SVM) are corrected to reduce the influence of incomplete radar sample data on the discriminant and evaluation results. Experiments show that the proposed method can achieve efficient jamming effect evaluation under asymmetric radar information conditions. [ABSTRACT FROM AUTHOR]

While various magnetic sensors have been developed over the years, the capability of passive wireless magnetic field detection is still lacking. Magnetic surface acoustic wave (MSAW) devices, combining magnetostrictive with piezoelectric materials, may be one of the candidates for wireless magnetic field sensing. This work proposes a novel microelectromechanical system (MEMS) MSAW resonator based on the AlN/Si/(Fe90Co10)78Si12B10 structure. The frequency responses of the resonator were measured when applying a dc magnetic field along the magnetic easy and hard axes. The results indicate that the resonator has higher magnetic sensitivity along the hard axis, with a maximum magnetic sensitivity of 11 kHz/Oe. When performing a magnetic field loop measurement for the hard axis, the resonator’s quality factor and resonance frequency showed almost the same variation tendency against the magnetic field. Moreover, the quality factor can attain about 3700 at the position of maximum magnetic sensitivity, which could simultaneously meet the needs of wireless interrogation and high sensitivity. Our work reveals that such an MEMS MSAW resonator has clear potential in the realization of wireless magnetic field sensors with miniaturization, low power, and high complementary metal–oxide–semiconductor (CMOS) compatibility for the future development of the Internet of Things (IoT). [ABSTRACT FROM AUTHOR]

Barium hexaferrite thin films with thickness of 8 \mu\m had been deposited on a sapphire substrate by radio-frequency magnetron sputtering. The results show that the grain size is about 2 \mu\m in diameter. The coercivity is about 2.2 kOe and the saturation magnetization is about 4000 Gs with remanence ratio of 0.58. Based on the sputtered thin films, a self-biased microstrip junction circulator had been developed. The measured S-parameters indicate that a nonreciprocal effect greater than 10 dB occurs at about 26 GHz. The maximum isolation is 44 dB and the minimum insertion loss is 27 dB. The origins of the large insertion losses have been discussed. [ABSTRACT FROM AUTHOR]