Xiaowen Xu

INTEGRAL-EQUATION ANALYSIS OF FREQUENCY SELECTIVE SURFACES USING EWALD TRANSFORMATION AND LATTICE SYMMETRY

In this paper, we present the space-domain integral- equation method for the analysis of frequency selective surfaces (FSS), consisting of an array of periodic metallic patches or a metal screens perforated periodically with arbitrarily shaped apertures. The computation of the spatial domain Greens function is accelerated by the Ewald transformation. The geometric model is simplifled by the lattice symmetry, so that the unknowns are greatly reduced. Time of fllling MOM matrix and solving linear system is dramatically reduced. Our technique shows much higher e-ciency when compared with the available commercial software and the existing methods published.

Study of the effect of a finite FSS radome on a horn antenna

In this paper, a horn antenna and FSS unit are designed separately. A planar radome composed by this FSS unit is placed in the near-field region of the horn, forming an antenna/radome system, to reduce the RCS of the horn. The radiation and scattering properties are calculated to study the effect of a finite FSS radome on the horn antenna.

Hybrid PMM-MOM method for analyzing the RCS of finite array

In this paper, a hybrid method (hybrid PMM-MOM method) is presented for effectively and accurately analyzing the RCS of finite array. This method divides finite array into two parts. The inner part of an approximate infinite periodic structure is analyzed by periodic method of moment (PMM); the outer part is then analyzed by method of moments (MOM). The accuracy of new method is much better than that of the pure PMM, and is almost as same as that of pure MOM. As for the memory, because pure PMM uses the periodic conditions, it takes up much less memory resources. For hybrid PMM-MOM method, because the inner part is calculated by PMM, calculation work concentrated in outer part. Consequently, compared to the exact MOM, the new method saves much more memory resources and computation time.

Method of spaceborne transmitter protection for electromagnetic interference problem

This paper presents a novel method to solve Electromagnetic interference (EMI) problems based on a real spaceborne transmitter. The EMI problem was solved with hardly increasing the weight of spaceborne transmitter, which is important for spaceborne electronic devices. It is proved with actual test example that this novel method could be operated expediently and put into excellent application.

Solving signal integrity problem of LVDS buffer with SigXplorer

Signal integrity(SI) problems for LVDS(Low Voltage Differential signaling) buffer is the bottleneck in receiver circuits design. This paper presents a novel simulation method to solve the real SI problem. Firstly, the SI problem which has been tested in the receiver equipment was reproduced by the software of SigXplorer. Then, the circuit was improved, and a stable signal was received by LVDS buffer in simulation. Finally, the method was proved to be correct by test. Some design experiences are summarized, which could be operated expediently and put into excellent application.

Simulation of the electric field Shielding Effectiveness in the range of 10kHz–1GHz

Experimental tests for SE (Shielding Effectiveness) of cylindrical copper shield and braided-wire shield in the range of 10kHz-1GHz have been taken. To reproduce the phenomenon of the tests, we create the simulate model. A new model of braided-wire shield is presented in this paper. SE of cylindrical surface shield and braided-wire shield are compared. The influence on SE of badly grounded cylindrical surface shield is also studied. Meanwhile, Comparison of SE of the braided-wire shield in different fraction of coverage is made. The results are well matched experimental test. The SE is bad as the frequency is relatively low. Shielding function is disabled if the shield is not well grounded. To go a step further, holes on the braided-wire shield are rotated along the radial direction of signal line, and SE are compared correspondingly. The results show that it influences the SE in 10kHz-100kHz region.

EMI filter design in Pspice

An application of the Pspice software is discussed through an example of an electromagnetic compatibility(EMC) test. Firstly the electromagnetic interference(EMI) signal is modeled and analyzed through the software, and then a low pass circuit is designed and emulated by the software. The EMI signal and the used signal that passed the low pass circuit are compared by the Pspice software. It is a real example of Pspice software used in EMC design, so it is much valuable for the design of EMC.

The parametric analysis of H-shaped patch antenna

The parametric analysis of H-shaped patch antenna is proposed. Double L-probe feed structure, introducing capacitive effect on the horizontal monopole, allows for compensation to the feed inductance due to long-probe. Using double feed technology achieves the symmetry of the radiation pattern. In this paper, the antenna performances with different parameters have been proposed. Compared to a conventional H-shaped patch antenna, the proposed configuration shows as much as 60% increment in beam width in y-z plane and 20.75% impedance bandwidth.

Investigation on the numerical performance of Calderón Multiplicative Preconditioner for electromagnetic scattering and radiation of 3-D open perfect electric conductors

Numerical performance of Calderón Multiplicative Preconditioner (CMP) for the electrical field integral equation (EFIE) of 3-D open perfect electric conductors (PECs) is investigated in this paper. The iteration count for achieving convergence in iteratively solving MoM linear equations from CMP preconditioned EFIE of several PEC scatters or antennas are presented. Numerical experiments show that for the analysis of thin wire-like open PECs especially in certain electric field excitation condition where the induced surface current is mainly along the wire axis, the CMP may be unfortunately helpless to iterative solver in handling EFIE-MoM linear equations. Empirical analysis is addressed that the invalidation of CMP in these cases is due to the fact that the RWG functions have weak ability to simulate surface currents with rotational component.

Research on probe position error analysis and correction in antenna time-domain near-field measurement system

For the antenna time-domain near-field measurement system, the probe position error is one of the most important error sources. Traditionally, many methods of its analysis and correction have been presented. However, these methods work only when the position error is much smaller than the AUTs wave length. Besides, the computation of these traditional methods is always large. This paper bases on the time-domain to frequency-domain transform of the practical time-domain measurements, applies a new method of unequally spaced near-field to far-field transformation to the measurement data. The new algorithm just needs the known theory locations of sampling points and the approximate probe position errors instead of the usual restriction that sampling points be located on a plane rectangular grid. The final measurements illustrate that the algorithm can eliminate the effect caused by probe position error which improves the accuracy of the test.