Genetic Algorithms in Electromagnetics

Genetic Algorithms in Electromagnetics......Page 4
Contents......Page 10
Preface......Page 14
Acknowledgments......Page 16
1. Introduction to Optimization in Electromagnetics......Page 18
1.1 Optimizing a Function of One Variable......Page 19
1.1.2 Random Search......Page 22
1.1.3 Golden Search......Page 23
1.1.4 Newton’s Method......Page 24
1.1.5 Quadratic Interpolation......Page 26
1.2 Optimizing a Function of Multiple Variables......Page 27
1.2.1 Random Search......Page 28
1.2.2 Line Search......Page 30
1.2.3 Nelder–Mead Downhill Simplex Algorithm......Page 35
1.3 Comparing Local Numerical Optimization Algorithms......Page 38
1.4 Simulated Annealing......Page 41
1.5 Genetic Algorithm......Page 42
2. Anatomy of a Genetic Algorithm......Page 46
2.1 Creating an Initial Population......Page 48
2.2 Evaluating Fitness......Page 49
2.3 Natural Selection......Page 51
2.4.1 Roulette Wheel Selection......Page 52
2.5 Generating Offspring......Page 54
2.7 Terminating the Run......Page 59
3.1 Placing Nulls......Page 62
3.2 Thinned Arrays......Page 71
4. Optimizing Antenna Arrays......Page 80
4.1 Optimizing Array Amplitude Tapers......Page 81
4.2.1 Optimum Quantized Low-Sidelobe Phase Tapers......Page 83
4.2.2 Phase-Only Array Synthesis Using Adaptive GAs......Page 86
4.3.1 Shaped-Beam Synthesis......Page 92
4.3.2 Creating a Plane Wave in the Near Field......Page 95
4.4 Optimizing Array Element Spacing......Page 102
4.4.1 Thinned Arrays......Page 103
4.4.2 Interleaved Thinned Linear Arrays......Page 105
4.4.3 Array Element Perturbation......Page 109
4.4.4 Aperiodic Fractile Arrays......Page 115
4.4.5 Fractal–Random and Polyfractal Arrays......Page 118
4.5 Optimizing Conformal Arrays......Page 122
4.6 Optimizing Reconfigurable Apertures......Page 129
4.6.2 Planar Reconfigurable Ribbon Antenna Design......Page 131
4.6.3 Design of Volumetric Reconfigurable Antennas......Page 132
4.6.4 Simulation Results—Planar Reconfigurable Cylindrical Wire Antenna......Page 133
4.6.5 Simulation Results—Volumetric Reconfigurable Cylindrical Wire Antenna......Page 136
4.6.6 Simulation Results—Planar Reconfigurable Ribbon Antenna......Page 139
5. Smart Antennas Using a GA......Page 150
5.1 Amplitude and Phase Adaptive Nulling......Page 153
5.2 Phase-Only Adaptive Nulling......Page 162
5.3 Adaptive Reflector......Page 165
5.4 Adaptive Crossed Dipoles......Page 177
6.2 GA Design of Electrically Loaded Wire Antennas......Page 186
6.3 GA Design of Three-Dimensional Crooked-Wire Antennas......Page 196
6.4 GA Design of Planar Crooked-Wire and Meander-Line Antennas......Page 201
6.5 GA Design of Yagi–Uda Antennas......Page 206
7.1 Reflector Antennas......Page 216
7.2 Horn Antennas......Page 219
7.3 Microstrip Antennas......Page 222
8. Optimization of Scattering......Page 234
8.1 Scattering from an Array of Strips......Page 235
8.2 Scattering from Frequency-Selective Surfaces......Page 240
8.2.1 Optimization of FSS Filters......Page 242
8.2.2 Optimization of Reconfigurable FSSs......Page 250
8.2.3 Optimization of EBGs......Page 253
8.3.1 Conical or Wedge Absorber Optimization......Page 255
8.3.3 Ultrathin Narrowband Absorber Optimization......Page 258
9.1 Selecting Population Size and Mutation Rate......Page 268
9.2 Particle Swarm Optimization (PSO)......Page 272
9.3.1 Introduction......Page 274
9.3.2 Strength Pareto Evolutionary Algorithm—Strength Value Calculation......Page 275
9.3.3 Strength Pareto Evolutionary Algorithm—Pareto Set Clustering......Page 276
9.3.4 Strength Pareto Evolutionary Algorithm—Implementation......Page 277
9.3.5 SPEA-Optimized Planar Arrays......Page 278
9.3.6 SPEA-Optimized Planar Polyfractal Arrays......Page 281
Appendix: MATLAB® Code......Page 286
Bibliography......Page 294
Index......Page 316