Design Of Dual-Band Dielectric Resonator Antennas

Due to their high efficiency, diversity of feeding forms, low cost and simple structures, dielectric resonator antennas show potential applications in the microwave, millimeter wave radar, wireless communication systems and many other fields. In this thesis, a dual-band single-polarized dielectric resonator antenna and a dual-band dual-polarized dielectric resonator antenna are designed. The author's major contributions are as follows:1. A dual-band single-polarized dielectric resonator antenna loading a metal strip is presented. The antenna can resonate in the high-frequency band of the dual bands by loading the metal strip. Although the antenna is of dual-band impedance performance, its radiation patterns at the high frequency are deformed. In order to improve the radiation characteristics and simplify the structure of the antenna, a dual-mode dielectric resonator antenna is proposed based on the aforementioned antenna. The antenna operates in dual bands using different operating modes. By optimizing the parameters, the antenna achieves a higher frequency ratio (FR) for the single feed point modes. A metal strip is loaded between the outer surface of the dielectric resonator and the probe to increase the coupling degree and the impedance matching performance. The resonating principle and the radiation characteristics of the antenna are studied by analyzing the distribution of the electric field vector on different resonant modes. Prototype of the antenna is fabricated and measured. The measured results indicate that the dual-band antenna has good impedance and radiation characteristics.2. A new dual-band dual-polarized dielectric resonator antenna is proposed. Due to the different length and width of the rectangular dielectric resonator, the resonant frequencies of the corresponding dominant modes are different. By feeding in two different surfaces of the rectangular dielectric resonator, dual-band dual polarized characteristic of the antenna is achieved. The antenna obtains good impedance matching at two frequency bands by optimizing the parameters of the metal microstrip loaded on the probe. HFSS software is also utilized to analyze and optimize the dimensions of the antenna. Prototype of the antenna is fabricated and measured. The measured results show that the dual-band dual-polarized dielectric resonator antenna has good radiation characteristics.