A Compact Description of Directive Antennas in Numerical Microwave Simulations Based on Complex Source Beams

While it is possible for the Physical Optic (PO) to simulate the wave propagation of an antenna in short range scenarios, it becomes more computational inefficient compared to a far-field assumption, because the enclosing surface of the antenna has to be sampled. In order to accelerate a PO in the near-field, in this work the representation of antennas with the Complex Source Beam (CSB) which is a compact method to represent a Gaussian like beam is investigated. Therefore, we present a method to find the parameters for the CSB to represent the emitted wave of an antenna. For this purpose, an optimization procedure is used to obtain the representation with the least deviation from a full wave simulation. A comparison with a full wave simulation shows that this method is highly accurate in the area of the main lobe which makes it fast to simulate measurement scenarios in the terahertz range in which mostly antennas with high directivity are used.