Yanlin Zou

Fast Analysis of Body-of-Revolution Radomes with Method of Moments

By taking advantage of the rotational symmetry, the electromagnetic characteristic of the body of revolution (BOR) radome is fast analyzed by the method of moments (MoM) based on the mode decomposition technique. First, the MoM matrix equation governed by the surface integral is established and the theoretical model is reduced in dimension by using the mode decomposition technique in view of the objects structure characteristic. Then, the integrals in the mode decomposition of the incident field are replaced by the fast Fourier transform (FFT), thus the decomposition coefficients of all modes on a given annulus can be fast and easily obtained through one FFT. Due to the surface equivalent electric and magnetic currents gotten by solving the matrix equations having the form of superposition of mode components, the analytical approach is used to substitute for the integral in the calculation of the far field pattern, so the computing time is greatly reduced. Examples are presented to demonstrate the accuracy and efficiency of the proposed method in this paper.

A Hybrid Fe-Bi Method for Electromagnetic Scattering from Dielectric Bodies Partially Covered by Conductors

A hybrid technique combines the finite element (FEM) and boundary integral (BI) methods is used to analyze electromagnetic scattering problems from structures consisting of an inhomogeneous dielectric body attached to perfectly conducting bodies. The hybrid approach takes advantage of the strengths of each numerical technique in order to solve problems that neither technique alone could model efficiently. Numerical results are presented to validate the accuracy and demonstrate the application of this method.

Dual-Band Yagi-Uda Antenna for Wireless Communications

A dual-band (915–935MHz and 1760–1805MHz) Yagi-Uda antenna with branch structures is proposed. The parameters of the branch structure are optimized to obtain the antenna that operates perfectly in the two bands. Prototype is fabricated and measured, and the results are in good agreement with the simulated ones. The presented antenna achieves directional radiation in the two operating bands, and gets the performances that VSWR<2, gain 5–6.6 dBi and front-to-back ratio 6–9.1dB, making it suitable for the non-fixed base station backhaul in wireless communications.

A novel dual-band Yagi-Uda antenna for wireless communications

A dual-band (915–935MHz and 1760–1805MHz) Yagi-Uda antenna with branch structures is proposed. The parameters of the branch structure are optimized to obtain the antenna that operates perfectly in the two bands. Prototype is fabricated and measured, and the results are in good agreement with the simulated ones. The presented antenna achieves directional radiation in the two operating bands, and gets the performances that VSWR<2, gain 5–6.6 dBi and front-to-back ratio 6–9.1dB, making it suitable for the non-fixed base station backhaul in wireless communications.

Broadband and Miniaturized Structure Loaded With Lumped Capacitors for Parasitic Current Reduction

A broadband and miniaturized structure for parasitic current reduction induced on the outer conductor of electrically coaxial cables is presented. The structure consists of a metallic sheet with 10 pairs of symmetrical L-shaped slots embedded. Lumped capacitors are loaded to miniaturize the entire size. The operation of the entire structure is similar to a series of parallel LC resonators. When the parasitic current flowing on the outer conductor of the coaxial cable, the equivalent parallel LC circuit can suppress the current efficiently at the broad bandwidth. Experimental and simulation results are presented and discussed. The structure can suppress the parasitic current at the 250-400-MHz band for a -10-dB transmittance.