As follows from recent investigations microwave energy treatment shows promises for a number of agricultural applications [1, 2]. On many occasions microwave energy radiates into nonscreened absorber medium. As oscillations decay exponentially in passage through a medium it results in noticeably nonuniform field strength distribution in depth. Thus the research for the more effective electromagnetic waves excitation is an urgent problem.

In this paper the use of focused aperture utilization is discussed. The focused aperture consisting of a linear or planar array of identical radiators is arranged near the medium boundary. By choosing of array elements excitation the field strength within the given area of medium can be substantially increased. This paper seeks to describe focusing algorithms as well as to estimate the field strength increasing in comparison with the uniform array utilizing.