Kaizhi Zhang

RADIATION ANALYSIS OF LARGE ANTENNA ARRAY BY USING PERIODIC EQUIVALENCE PRINCIPLE ALGORITHM

In this paper, an improved equivalence principle algorithm is proposed to solve the radiation problems of large antenna arrays with periodic structures. This method is a hybridization in which the typical scheme of periodic Greens function is combined with the original equivalence principle algorithm. The repeated elements are changed from the original antenna units into the surfaces enclosing the original ones. The proposed approach is compared with periodic method of moments which is based on the integral equation and the periodic Greens function. Numerical results validate the feasibility of the improved method.

Calibration method of phased array based on near-field measurement system

A new phased array calibration method based on near-field measurement system such as NSI is proposed in this paper. By measuring a single element antenna near-field and array near-field, calibration parameter is extracted from measured data with twice Fourier Transformation and once Inverse Fourier Transformation. Both amplitude and phase calibration is realized by this method in a very short time. A calibration example of a one-dimensional array is used to validate the proposed method.

Conformal antennas based on holographic artificial impedance surfaces

Advances in artificial impedance surface conformal antennas are presented. A detailed conical impedance modulation is proposed for the first time. By coating an artificial impedance surface on a cone, we can control the conical surface wave radiating at the desired direction. The surface impedance is constructed by printing a dense texture of sub wavelength metal patches on a grounded dielectric slab. The effective surface impedance depends on the size of the patches, and can be varied as a function of position. The final devices are conical conformal antennas with simple layout and feeding. Simulated results are presented, and better aperture efficiency and lower side lobe level are obtained than our predecessors [2].

ANALYSIS OF MULTI-SCALE PROBLEM ABOUT ANTENNA MOUNTED ON ELECTRICALLY LARGE PLATFORM BY USING CONNECTED EPA-PO

In this paper, a hybrid method combining equivalence principle algorithm with physical optics is proposed to solve the radiation problem of antenna mounted on electrically large platform. It is based on domain decomposition method which is a scheme for multi- scale problems. Equivalence principle algorithm can simulate antenna accurately, and physical optics is an asymptotical method to obtain current distribution on the electrically large platform. Continuity of currents is considered when the conductor on the platform is decomposed into two parts by the equivalence surface. In addition, a preconditioning for the hybridization of equivalence principle algorithm and physical optics is discussed. Numerical results demonstrate the feasibility of the hybrid method.

Folded dual-band slot antenna with further reduced size

A microstrip-fed folded dual-band slot antenna with further reduced size is presented. The antenna works for two bands which are 880MHz–960MHz and 1710MHz–2690MHz. whats more, the folded slot antenna just occupies a relative small size for wireless communication application about 28mm by 90mm by 4.8mm (W*L*H). Good agreements between simulation and testing results are achieved. As a balance mode antenna, little surface current is found in the ground of the slot antenna.

Hybridization of Periodic Equivalence Principle Algorithm, Equivalence Principle Algorithm, and Physical Optics for Analysis of Large Finite Antenna Array with Perfect Electrically Conducting Object

ABSTRACT In the solution of a radiation problem on a large-scale antenna array with a large perfect electrically conducting object, the equivalence principle algorithm hybridized with physical optics has been used to accelerate the calculation. However, the efficiency of this hybridization will be low if the number of elements in the antenna array is large. This article proposes a novel method to speed up the equivalence principle algorithm hybridized with physical optics by introducing the periodic equivalence principle algorithm. The calculation of the couplings among the elements will be simplified, and the elapsed time will decrease. At the same time, the total memory required will be saved.

Solution of finite antenna array by using PEPA-EPA

In this paper, one hybridized method, in which the periodic equivalence principle algorithm is combined with the equivalence principle algorithm, is proposed to solve the finite antenna array with large scale. This method based on the domain decomposition method is more efficient than full-wave methods and more accurate than asymptotical methods with periodic Greens function. Moreover, this approach avoids multi-region iterative algorithm. The numerical results reveal the feasibility of the proposed method.

A compact wideband aperture-coupled antenna with high polarization purity and high front-to-back ratio for 5 GHz WLAN applications

In this paper, A novel compact wideband aperture-coupled antenna with high polarization purity and high front-to-back (F/B) ratio is proposed for 5 GHz WLAN applications. The high polarization purity is attributed to the aperture-coupled feeding mechanism, and with the aid of a quarter-wavelength choke, the F/B ratio can be increased. Simulated results show that the proposed antenna occupying a compact size of 0.46λ₀×0.46λ₀×0.24λ₀ (λ₀ is the lower frequency wavelength) achieves a bandwidth of 27% for 10-dB return loss ranging from 4.66 to 6.12 GHz. The F/B ratio is above 22 dB and the cross-polarizations in both E- and H- planes are lower than -44 dB within the operating bandwidth.

Solving the Radiation Problem of Large-Scale Antenna Array by the Accelerated Periodic Equivalence Principle Algorithm

In this letter, an updated periodic equivalence principle algorithm is proposed to solve the radiation problem of large-scale antenna array when the antenna elements are placed closely. The equivalence surfaces enclosing the antenna elements are touched with each other, and the elapsed time in the translation procedure of the periodic equivalence principle algorithm will decrease. The efficiency will increase correspondingly. The numerical results will reveal the feasibility of the proposed method.

A novel hybrid method with equivalence principle algorithm and physical optics for antenna problems on electrically large platform

an integral equation approach based on domain decomposition method (DDM) is presented to solve antennas problems on electrically large platform. This proposed approach combines equivalence principle algorithm (EPA) and physical optics (PO). The number of unknowns decreases and computational efficiency increases. More importantly, EPA-PO avoids iterative Multi-Region procedure and obtains the final currents directly after considering interactions of different sub-domains. A numerical example will be shown to validate the approach.