Optimization of Surface-Acoustic-Wave Withdrawal-Weighted Filters Using Genetic Algorithms

Instead of the conventional 0-1 sequence, a new sequence has been devised, which is appropriate for optimizing withdrawal-weighted filters, using genetic algorithms. The sequence consists of durational numbers of continuous 0s and 1s, and the search area is reduced to much smaller than the total configuration space. A filter whose relative 3 dB bandwidth is 0.5% is optimized. The method yields a maximum sidelobe level of -56.1 dB, while the level of the initially synthesized filter is -41.5 dB. The calculated results show that the method is effective for nonlinear optimization of withdrawal-weighted filters.