| The novel dielectric antenna is a popular research direction now for its intrinsic advantages of traditional antennas such as relatively wide bandwidth, high gain and low cost. In millimeter wave band and terahertz band, the skin effect of metal materials can be very significant. Nevertheless, dielectric antenna mainly consists of dielectric, thus it can avoid the skin effect and have a high radiation efficiency. For this reason, dielectric antenna has a potentially high application value in millimeter wave band and terahertz band. Two kinds of novel dielectric antennas are proposed in this paper. One is polarization reconfigurable dielectric resonator antenna, the other is millimeter wave dielectric resonator reflectarray antenna.Polarization reconfigurable dielectric resonator antenna is investigated in the first part. The antenna is fed by a quasi-lumped quadrature coupler(QLQC) to realize four polarization patterns, which are left-hand circular polarization, right-hand circular polarization, x-linear polarization and y-linear polarization. For my best knowledge, it is the first dielectric reson ator antenna that can realize four polarization modes. The design is simulated, fabricated and measured. Reasonable agreement between measurement and simulation results is observed.The second part is the study of a millimeter wave dielectric resonator reflectarray antenna. In the first structure, double-layer dielectric cuboid is used as reflect element to expand bandwidth of the reflectarray. Different elements have different heights to realize different reflect phases. A 20*20 elements reflectarray is constructed and simulation results show that the reflectarray has a 40% 1d B gain bandwidth. In the second structure, the dielectric cuboids which have different permittivities and same size are used as reflect element. Simulation result shows that the 20*20 reflectarray has a 23 d Bi gain in boresight direction. At last, the fabrication method is discussed. |
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