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Tian X.,Shanghai JiaoTong University | Xiao G.,Shanghai JiaoTong University | Fang J.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2013

New and concise analytical formulae for calculating time domain potentials from Rao-Wilton-Glisson (RWG) type sources are derived in this paper, which can be applied to efficiently evaluate the interaction between two RWG elements in time domain, as is required in methods such as marching-on-in-time (MOT) for time-domain-integral-equations (TDIEs). Compared with previous analytical expressions, formulae in this paper are readily deduced through the RWG coordinates which are very compact to program without finding and paring the intersecting points between the concentric time spheres and the RWG triangles or categorizing the geometric relations of the observation point and the triangles into different occasions. Undifferentiated EFIE, MFIE and CFIE are applied to provide numerical examples that verify the efficacy of these formulae. © 2013 IEEE. Source


Xiao G.,Shanghai JiaoTong University | Tian X.,Shanghai JiaoTong University | Luo W.,Shanghai JiaoTong University | Fang J.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle
IET Microwaves, Antennas and Propagation | Year: 2015

Impulse responses to the time-domain integral equations (TDIEs) using marching-on-in-time (MOT) scheme are discussed in this study. It can be seen clearly that the interior resonance currents are included in the impulse responses of the time-domain electric field integral equation (TDEFIE) and the time-domain magnetic field integral equation (TDMFIE), but not in those of the time-domain combined field integral equation (TDCFIE), while spurious DC solenoidal currents are only included in the TDEFIE. Analysis shows that the MOT-TDMFIE is basically exponentially convergent, and the MOT-TDCFIE usually converges to a small constant value, while the MOT-TDEFIE is basically unstable. The stability properties are justified by the eigenvalues of the corresponding systems. This study also shows that it is possible to solve time-domain integral equations (TDIEs) using their impulse responses truncated according to the maximum physical size of the scatterer. © The Institution of Engineering and Technology 2015. Source


Cao Y.,Shanghai Radio Equipment Institute | Cao Y.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle | Wang X.,Shanghai Radio Equipment Institute | Wang X.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle
Progress in Electromagnetics Research Symposium | Year: 2014

Metamaterials (MMs) refer to a class of artificially engineered structures comprised of electric/magnetic resonant building blocks much smaller than the operating wavelength. The extraordinary electromagnetic responses of MMs, not available for naturally occurring materials, have attracted intensive investigations on the underlying physics as well as related applications. In recent years, MMs-based antennas are widely studied and proved to have great potential in improving the radiation performance. In this paper, a MMs-based Febry-Perot cavity antenna with wide viewing angle is proposed about 14 GHz. The antenna consists of a high-impedance surface which works as an artificial magnetic conductor (AMC) at resonance frequency and a partially reflective surface (PRS). The AMC loading contributes to the low-profile and high-gain property of the antenna, as the AMC ground plane gives a near-zero phase shift in contrast to conventional metal sheet ground plane. The lateral size of the antenna is only about 3λ × 0:6λ; and the thickness is about λ/5. Metal walls surrounding the limited aperture are introduced to prevent the leakage of cavity mode and improve the radiation pattern, which also protects the antenna from external electromagnetic environment. The MMs-based high-gain antenna has a broad beam width in H-plane, which may be applied in ETC and RFID system. Source


Li L.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle | Wang X.B.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle | Tong G.D.,Tongji University | Liang Z.C.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle
Applied Mechanics and Materials | Year: 2013

The electromagnetic properties of the material have been paid much attention as time goes by. The electronic large-scale material simulation is always a big problem. Parallel processing simulation codes[1][2] is a good choice and a new method is proposed to simulate only one quarter of the structure and finally a small structure patch antenna with wide material is introduced to validate the method. © (2013) Trans Tech Publications, Switzerland. Source


Liao Y.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle | Cai K.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle | Hubing T.H.,Clemson University | Wang X.,Shanghai Key Laboratory of Electromagnetic Environmental Effects for Aerospace Vehicle
IEEE Transactions on Antennas and Propagation | Year: 2014

An equivalent circuit consisting of eight frequency independent lumped elements is derived for center-driven normal mode helical antennas. The equivalent circuit is composed of two parts; a five-element circuit representing the wire antenna and a three-element circuit for the helical turns. Comparison of the calculated input impedance of the equivalent circuit with full-wave simulations demonstrates reasonable agreement over a broad frequency range that includes the first resonant frequency, where the antenna usually operates. Application of the equivalent circuit does not require an EM solver and it is readily implemented in circuit simulators. © 2014 IEEE. Source

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