Study Of Low-profile High-gain Magneto-Electric Dipole Antennas

As we know, Long term evolution (LTE) is the next step forward in cellular3Gservices, which is based on a3GPP standard and is a way for cellular communications tooperate at high data rate. In order to meet the requirements of LTE systems, antennas withexcellent performance, such as high gain and compact size, have received significantattention in the past few years.In this thesis, two types of novel magneto-electric dipole antennas are proposed. Atypical magneto-electric dipole antenna integrates an electric dipole and a magnetic dipoletogether and excites them simultaneously using coaxial feed, which exhibits high gain, lowcross-polarization and back radiation levels. However, traditional magneto-electric dipoleantennas normally has relatively large size and operating in single frequency band, whichmay not be very suitable for high speed and miniaturized LTE communication systems. Inorder to solve these problems, a novel single-band magneto-electric dipole antenna and anovel dual band magneto-electric dipole antenna have been proposed in this thesis. Theproposed antenna has two shorted quarter-wave microstrip patch antennas, operating asmagnetic dipoles, and two planar electric dipoles, which are connected with magneticdipoles. These dipoles are excited simultaneously by a coaxial-to-microstrip impedancetransformer, and the radiation patterns of the electric dipole and magnetic dipole antennain the planes of the two polarizations can be complement to each other. Gain of9.25dBi to10.4dBi in the operating band (center frequency of3.5GHz) has been achieved for theproposed single band antenna. The dual-band antenna is designed to operate at the centerfrequencies of1.45GHz and3.5GHz, the gain can reach3dBi to5dBi and7dBi to9dBi,respectively.