Design Of Focused Antenna Arrays And Dual Band Dual Circular Polarization Antennas

Focused antennas are a kind of antennas which used to focus electromagnetic energy to a small area in the near field region and reduce the energy spreading in the free space. With the development of the aircraft and communication engineering, the focused antennas may be used in microwave power transmission, non-contact sensing, medical treatment, and other areas that need a high power density at a moderate point close to the antenna aperture.In this article, we present a novel design method for focused array. Compared with traditional methods applying the continuous electric distribution on discrete array elements, this new method achieves the desired excitation of each element by optimizing the power transmission efficiency. The design based on this method has taken the mutual coupling into consideration. Besides, the focal distance is positioned more precisely and easy to be controlled.Two 4x4 elements focused antenna arrays with feeding network on different sides and a 8x8 elements focused antenna array are designed to verify the concept, which are helpful to large scale antenna array design.For dual band and dual circular polarization antenna, two novel microstrip slot antenna with simple structure are designed. Both of the two antennas are designed with two sides structure and fed by a microstrip line, which avoiding complex structure and feeding network. Meanwhile, one of the proposed antenna is designed for BouDou Navigation System, which can be applied in many areas.