微波在分层媒质中的近场聚焦

本文分析讨论了天线口面附近有分层煤质(两层)情况下的聚焦场分布。在分析中,引入了赫兹电磁位,利用平面波谱理论,得到了场的平面波谱函数和其赫兹位的关系式。通常,求分层介质中的场只是在平面波情形下求取。本文提供了一种在介质前面有任意源分布时,求取分层介质中场分布的方法。对于天线口面上的聚焦电流分布,求得了聚焦点及其周围附近的场分布。在求解过程中,我们绕开了复杂的费涅尔积分,而是在其谱域中,对其谱函数进行k_x,k_y积分。再引用鞍点近似方法,得到了场的近似表达式。最后进行了理论和实验的比较,验证了这种方法的正确性。

The Near-Field Microwave Focusing in the Layer Mediums

The microwave focusing in the layer mediums near the antenna aperture is discussed and analyzed in this article. In analysing the Hertz potentials are introduced, then, by the plane-wave spectrum theory, the relationship of the Hertz potentials arid the electromagnetic field is obtained. The field in the layer mediums is usually obtained when the field source is assumed to be a plane-wave. In this article, however, a new method of getting the field distribution in the layer mediums in case of an arbitrary field source is put forward. For the focusing current distribution over the antenna aperture, the authors have got the field distribution diagrams of the focus and around it. In the solving process, avoiding the complicated Fresnel Integral, the authors have integrated the spectrum functions in the spectrum range - kx, ky.The approximations are obtained from the exact solution by the saddle - point integration. Finally, the method is verified by comparing the experiment results with the theory.