Comparison between real and power optimisation methods for arrayssynthesis of antennas

The authors compare real and power far field patterns synthesis arrays. The synthesised pattern is an optimum approximation to the prescribed power pattern in a minmax sense. A comparison between real and power formulations is realised for shaped (cosecante) and pencil beams     

Harmonical characterization of a microstrip bend via the finitedifference time domain method

A 90° microstrip bend is characterized using a time-frequency method based on the finite-difference-time-domain (FDTD) method. Time evolution of the currents generated by FDTD are Fourier transformed to lead to S-parameters and the radiated powers characteristic of the microstrip bend. The method for calculating both radiation and surface wave losses is developed for microstrip structures. The results of the 90° microstrip bend are compared with the results of the mitered microstrip bend     

Transient analysis of a space-borne microstrip patch antennailluminated by an electromagnetic pulse

The transient response of a microstrip patch antenna excited by a plane wave is studied using a finite difference algorithm applied to a total field version of Maxwell's curl equations in the time domain. A wide bandwidth study shows different behavior in the antenna, depending on the frequency and angle of incidence of the wave. At low frequencies, the voltage in a 50 Ω load is proportional to the derivative of the incident Eⁱ field. With increasing frequency, parasitic oscillations appear to be due to the short-circuited patch. In addition, at high frequencies, antenna sizes and wavelength are of the same order. The voltage contains oscillations at the frequency of the TM mode of the antenna. Two patterns of coupling appear: (1) capacitive coupling, where the current on the patch rises at the wire-metallic plane junction and spreads on the patch and on the finite ground plane; and (2) coupling due to the scattering, where the current rises at the edges of the patch and on the finite ground plane     

欧洲城市中的性别主流化运动

欧洲城市和区域理事会（CCRE）下属的妇女委员会于2004年在欧盟范围内进行了一次调查，寻找真正适于妇女生存与发展的城市。调查中没有发现理想的城市，但是发现许多值得效仿的城镇，其中很多城市都制定了性别政策。     

中法交流:一树百获

华揽洪(LéonHoa),吴良镛,崔恺,栗德祥,张祖刚,齐欣,单黛娜,这七位建筑师属于三代,年龄从45至92岁。他们是这期特刊的主要人物。为什么把他们放在一起,他们之间有什么共同之处吗?他们中的几个人可以讲流利的法语,在法国曾居住、工作、学习过,但这不是把他     

Absorbing surface impedances of lossy layers in the finite difference time-domain method

In this paper the time-domain surface impedances of an homogeneous absorber layer, are given for the vertical and horizontal polarizations, or respectively for the electric field perpendicular or parallel to the incidence plane. It turns out that the application of the concept in finite difference time-domain (FDTD) in absorbing surface impedances boundary conditions, gives results in good agreement with analytical Fresnel reflection coefficients.     

Mécanisme de l’évolution des champs électromagnétiques dans un simulateur de grandes dimensions. Projet d’un simulateur semi-rhombique

The purpose of this paper is to evaluate theoretically and experimentally the transient electric field in anemp simulator. Using a time domain analysis, the mechanism of the field deformation can be analysed and consequently modifications can be introduced in the conception of new simulators (for example: rhombic simulator).     

Time-domain surface impedances of lossless Debye media

In a previous paper, a surface impedance formalism was given. Its application to interfaces modelling between homogeneous and frequency dependent media, was of great interest in the finite difference timedomain (fdtd) codes. In this paper, an extension of the method to dispersive media is presented. Applying this formalism to lossless Debye medium, the analytical expressions of the time- domain surface impedances are given. The implementation in a fdtd code permits then a numerical verification of the results in relation to the Fresnel method.     

TE11 modes in straight and curved circular waveguide with `deformed? cross-section

The two polarisations of TE11 modes are shown to be non-degenerated in a circular waveguide when its cross-section is `conveniently deformed?. So the crosspolar discrimination is improved in such a curved guide. This permits the use of this structure as an antenna feeder at frequencies about 12 GHz.