A simple design of multi band microstrip patch antennas robust to fabrication tolerances for GSM, UMTS, LTE, and Bluetooth applications by using genetic algorithm optimization

Design of multiband antennas with low volume is of practical interest for the ever growing wireless communication industry. In this regard, the design of a small multi band microstrip patch antenna (MPA) for GSM900 (880-960 MHz), GSM1800 (1710-1880 MHz), GSM1900 (1850-1990 MHz), UMTS (1920-2170 MHz), LTE2300 (2305-2400 MHz), and Bluetooth (2400-2483.5 MHz) applications by using a genetic algorithm (GA) is proposed. The proposed GA method divides the overall patch area into different cells taking into account that cells have a small overlap area between them. This avoids optimized geometries with certain cells having only an infinitesimal connection to the rest of the patch. Therefore, the proposed method is robust for manufacturing. A shorting pin is also included for impedance matching. GA optimization combined with finite element method (FEM) is used to optimize the patch geometry, the feeding position and the shorting position. A prototype has been built showing good agreement with the simulated results. The optimized MPA has a footprint of 46 mm × 57 mm.