An improved design of industrial, scientific and medical (ISM) band folded-patch antenna is presented. It is simple to manufacture and has less potential for manufacturing error than a previously presented design. Jumping genes evolutionary algorithm is applied for optimising antenna performance. A solution selection methodology is also designed to select the best solution among several alternatives after the optimisation process. Antenna hardware was fabricated and measured to verify the simulation result. Both simulated and experimental results are in good agreement. It is capable of covering three ISM bands at 2.400-2.480, 5.150-5.350 and 5.725-5.825 GHz, which is ideally suitable for short-range wireless applications.