Investigation On Wideband Magneto-electric Dipole Antenna For Mobile Communication

In the past few decades,motivated by the rapid development of mobile communication systems,there has greatly increased the demand for wideband antennas with excellent electrical characteristics.Magneto-electric dipole antenna is a novel wideband unidirectional antenna,which can meet the needs of modern mobile communication system for wideband unidirectional antenna.The dissertation has focused on the research of wideband and low-profile magneto-electric antenna and can be summarized as the following sections:Firstly,a wideband magneto-electric dipole antenna composed of a printed folded dipole and a microstrip slot antennas is proposed.Measured results show that the relative bandwidth of the microstrip slot antenna for₁₁<-10dB is 50.4%.An antenna gain of 8.9±1.5dB is achieved over the operating frequencies.Secondly,a miniaturized artificial magnetic conductor(AMC)is proposed.Then,a wideband magneto-electric dipole antenna composed of a dipole and a bowtie slot antenna uses the miniaturized AMC as a reflector to reduce the height of the antenna.Compared with using PEC reflector,the height of the antenna using AMC reflector is reduced by 0.124?.Measured results show that an impedance bandwidth of 57.2%for₁₁<-10dB from 2.88 to 5.19GHz is achieved.An antenna gain of 8±0.8dB is achieved over the operating frequencies.Subsequently,a wideband magneto-electric dipole antenna composed of a shorted bowtie patch antenna and a printed dipole is proposed.By adding a pair of parasitic patches above the printed dipole,the bandwidth of the antenna is broadened.Measured results show that an impedance bandwidth of 84.7%for SWR<2 from 2.09 to 5.16 GHz is achieved.An antenna gain of 9±2.2dB is achieved over the operating frequencies.Finally,by opening a pair of triangle-shaped slots on the shorted patch of a typical magneto-electric dipole antenna,a low-profile wideband magneto-electric dipole antenna is proposed.The height of the magneto-electric dipole antenna is reduced from 0.25?to 0.167?.Measured results show that an impedance bandwidth of 53%for SWR<2 from 3.08 to 5.3GHz is achieved.An antenna gain of 9.3±1.7dB is achieved over the operating frequencies Based on the low-profile linear polarized magneto-electric dipole antenna,a low-profile±45°dual-polarized magneto-electric dipole antenna is proposed.The height of the dual-polarized magneto-electric dipole antenna is reduced from 0.25?to 0.18?.Simulated results show that the common bandwidth of the two ports is 44.9%for SWR<2 from 3.23 to 5.1GHz.The isolation between the two ports is more than 28dB and the antenna gain is approximately11.5±1.6dB and 11±1.5dB for port 1 and port 2 respectively over the operating frequencies.