Different soft computing techniques like GA, ANN, ACO, PSO, BFOA, etc. are available. Antenna Parameter optimization has been done by GA and ANN. Besides these techniques which techniques are recently being used?
It definetely depends on the nature of the problem. However, my first choice would have been among NSGA-II, CLPSO and SADE (it is not only the performance characteristics of algorithm that count, but also its easy implementation)
I have used two different self-adaptive differential evolution algorithms for antenna optimization and they are quite robust. Another choise could be composite DE which we have used in recent paper combined with ANNs The doi is 10.1109/LAWP.2013.2251994.
I could email you the papers if you are interested.