**Successful Applications**

20 Will-be-set-by-IN-TECH

[39] Wong, M.-L. & Wong, T.-T. [2006]. Parallel hybrid genetic algorithms on consumer-level graphics hardware, *Proc. of the Congress on Evolutionary Computation*, pp. 2973 –2980. [40] Wong, M., Wong, T. & Fok, K. [2005]. Parallel evolutionary algorithms on graphics processing unit, *Evolutionary Computation, 2005. The 2005 IEEE Congress on*, Vol. 3,

[41] Yu, Q., Chen, C. & Pan, Z. [2005]. Parallel genetic algorithms on programmable graphics hardware, *Proc. of the international conference on Advances in Natural Computation*,

pp. 2286–2293 Vol. 3.

Springer-Verlag Berlin, pp. 1051–1059.

**Chapter 6** 

© 2012 Casula and Mazzarella, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Casula and Mazzarella, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

**Structure-Based Evolutionary Design Applied** 

Antennas are 3D structures, so, at variance of other MW subsystems like filters and couplers, their design has been a matter of intuition and brute-force computations from the beginning (Silver, 1949; Elliott, 1981 just to remember a few). Therefore, an antenna design has been faced at different levels, from simple formulas (Collin, 1985) to sophisticated synthesis techniques (Orchard et al., 1985; Bucci et al., 1994), and from simple heuristic models (Carrel, 1961) to modern global random optimizations, such as GA (Linden & Altshuler, 1996, 1997; Jones & Joines, 1997) and PSO (Baskar et al., 2005), with their heavy

Moreover, an antenna design problem is typically divided into two phases, namely an external problem (the evaluation of the antenna currents from the field requirements) and an internal problem (the design of the feed structure needed to achieve those currents, and the input match) (Bucci et al., 1994). In many cases these two phases are almost independent, but for some mutual constraints, as in reflector (Collin, 1985) and slot (Costanzo et al., 2009; Montisci, 2006) or patch (Montisci et al., 2003) array synthesis, since in these cases there is a clear boundary separating the feeding and radiating part of the antenna. In other problems, as in wire antennas design (Johnson & Jasik, 1984), such phases are strictly interconnected, since no clear-cut divides the two parts. For parasitic wire antennas, the interconnection is even stronger, since every element acts as feeding and radiating part at the same time.

The traditional approach to the design of wire antennas starts by choosing a well-defined structure, whose parameters are then optimized. However, a good design requires also a continuous human monitoring, mainly to trim the initial structure to better fit the antenna specifications. A trimming which requires both a deep knowledge and experience in order to effectively change the structure under design. As a matter of fact, such traditional approach is quite expensive, and therefore design techniques without human interaction are

**to Wire Antennas** 

http://dx.doi.org/10.5772/48249

**1. Introduction** 

computational loads.

Giovanni Andrea Casula and Giuseppe Mazzarella

Additional information is available at the end of the chapter
