A compact antipodal Vivaldi antenna (AVA) with metamaterial half-lens (MHL) for beam control is proposed. The proposed AVA has three different beam forms in the operating frequency band, including end beam from 3 GHz to 9 GHz, beam splitting at 12.2 GHz, and 30 ∘ beam deflection at 13 GHz. Furthermore, it can perform 18 ∘ beam scanning by adjusting operating frequency from 12.7 GHz to 13.5 GHz. The simulation indicates that the proposed AVA has a −10 dB impedance bandwidth of 143.6% (2.3–14.0 GHz) and a −3 dB gain bandwidth of 100% (4.5–13.5 GHz), which is consistent with the experimental results. Besides, the gain of the proposed AVA has an improvement of about 2 dB in the working band. As a new method to control the beam, the loading of MHL realizes the design of a small size and multi-function antenna, which can be widely used in wireless communication systems.

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Corrosion is a very common defect for pipes under the sea after some service time, and it causes a deterioration of a pipe’s strength due to the reduction of the tube wall thickness. To provide a reliable assessment on the residual strength of a pipe after corrosion is very important in the safety evaluation of such pipes. This study presented both experimental and numerical investigations on the static strength of corroded pipes. Flexural test on a corroded pipe is carried out, and the tested results prove the decrease of the static strength for this corroded specimen. Furthermore, a finite element modeling method is proposed, and the reliability of this model is evaluated through the comparison with experimental results. Using this finite element model, effect of some corrosion sizes on the residual strength of the pipes has been analyzed and discussed.

At present, main AC power systems of advanced fighters all apply digital controllers with microprocessors. The signal input and output circuits are vulnerable to the effects of electromagnetic interference, which may cause air-power-off fault. The paper analyzes the electromagnetic environment on the aircraft, discusses the airborne electromagnetic compatibility by comparing domestic and international contents and limitations of the electromagnetic standard. Furthermore, it proposes measures to resolve the electromagnetic compatibility