Complex Antenna Optimization

摘要

Complex electromagnetic problems arise due to various applications in science and technology that are becoming a necessity in our daily activities. As systems become more complex their design and implementation require novel topologies and sophisticated optimization tools to meet the challenges. One of the key components in commercial and military communication systems is an antenna which serves as an energy conversion device from an electrical source into radiated electromagnetic fields. However, system specifications require optimized design for antennas in terms but not limited to higher gain, broader bandwidth, smaller size, proper radiation pattern and polarization and lower cost. Addressing these complex issues requires an optimized solution based on sophisticated numerical electromagnetic solvers. Here, Fano-Chu (1950) limits which were proposed for electrically small antennas have been extended to rather larger structures. The basic premise for the concept is that volume antenna (more conducting elements within specified volume) yields higher gain. Starting from this assumption an antenna structure based on Moxon antenna has been developed to produce circularly polarized antenna for satellite communications (SATCOM), RFID tag reader and Global Positioning System (GPS). Cross-Moxon elements were redesigned to optimize gain and lower cross-polarization as well as maintain low profile and adequate bandwidth. Designed antennas were fabricated and measured leading to significant size reduction, improved higher gain, reduced cross-polarization and lower cost compared to commercially available state-of-the-art antennas.