Microstrip Antenna Optimization And Design Based On Genetic Algorithm

Genetic algorithm has become a best way for antenna optimization based on its efficiently outstanding features. Optimizing the structure parameters that affect antennas' bandwidth with genetic algorithm to realize addition of effective bandwidth is the mainstream direction for modern antenna to design, and has great theoretical significance and broad applied prospects.Firstly, a dual-frequency microstrip antenna(3.5 GHz/5.2 GHz) was optimized with the program of genetic algorithm, then its relative bandwidth can reach about 23% with a resonant frequency of 3.5 GHz, and the other one can reach about 29% with a resonant frequency of 5.2 GHz meanwhile after being optimized, this achieves dual-band working and meets UWB's design requirements, and also covers the Wimax and WLAN frequency band, so it has practical value in the field of communication.Then, two pairs of planar inverted-F antennas were designed. The first one was single-frequency microstrip antenna, and its optimized resonant frequency was 2.4GHz which was fully consistent with the expected value and the relative bandwidth reached about 9% which was completely covering the standard WLAN802.11 b frequency range. The other one was dual-band microstrip antenna whose optimized resonant frequencies were 0.925 GHz and 2.41 GHz, which were basically consistent with the expected values, 0.9GHz and 2.4GHz, and it has practical value.in the mobile phone communication.Finally, two pairs of reconfigurable antennas were optimized, and the first one, frequency reconfigurability, was an array antenna, which consists of a square shape main radiating patch and eight symmetrically surrounded small parasitic patches with the same square shape. The main radiating patch and the parasitic patches are connected through switches, by controlling the switches' on-off state, the frequency's reconfigurability can be achieved. Four switches being closed between the main radiating patch and the parasitic patches and the other switches were off, the antenna could work in X-band with its resonant frequency of 9 GHz and the relative bandwidth was about 11% after optimizing. When all switches were closed, the antenna would work in C-band. Then using the genetic algorithm to optimize a set of switches to make the antenna work in S-band, Final the antenna could work in X-band, S-band and C-band, and achieved frequency's reconfigurability. The other one, Pattern reconfigurability, was single-frequency antenna. Its relative bandwidth was about 8% after optimizing, and the far field radiation pattern had obvious symmetry and no coincidence by closing the corresponding switches, then the pattern reconfigurability of far field radiation was realized perfectly, achieving optimization objectives.