Reflector antennas are widely used in microwave and millimetre-wave communications and radar systems demanding large data rates due to their high efficiency capability, relative mechanical simplicity and inherent broadband characteristics. In fact, every student of Communications via radio waves must learn, at least, the main characteristics of this kind of antennas. In order to facilitate the comprehension of the reflector antennas performances to under-graduate and post-graduate students, a free MATLAB tool called ICARA was developed. This software allows the design and analysis of single and dual reflector antennas using the method of Physical Optics, completed with Physical Theory of Diffraction. There are several degrees of complexity depending on the course employed.
The principal features and characteristics are the following:
-Reflector geometry configuration: It allows the interactive design of the classical configurations of single parabolic reflector antennas and also the Cassegrain and Gregorian dual systems. Additionally, arbitrarily shaped reflectors can be introduced by adequate files defining the surfaces numerically. Surfaces are divided into triangular patches. A constant-amplitude and linear-phase model of the PO current is assumed.
-Feed configuration: Different configurable feed models are supported: disk of electric current, cos-q single and array of cos-q elements. For the array of cos-q elements feed, the contribution of each element to the radiated field of the antenna is computed and stored separately in order to allow the user modify their excitations and check the combined pattern in real time. Besides, feed configuration can be made reading the copolar and crosspolar components of its pattern from an external file.
-PO Analysis: The direct radiation of the feed (spillover) and the subreflector blockage can be taken into account or ignored by the user. To achieve this, up to four independent radiation sources are considered: direct radiation of the feed, surface currents over the subreflector produced by the feed, surface currents over the main reflector produced by those of the subreflector and “blockage currents” produced by the main reflector on the subreflector. The far field can be computed and plotted for different kinds of 2D cuts, contour plots of 3D views. The focal region fields can be also computed along principal axis or across principal planes. Numerical results can be exported to ASCII files.
-PTD Analysis: The radiation of the rim has been included in this version using the Physical Theory of Diffraction.
Most of the features of this software are included in a public version (http://go.to/antenas).