The Radiation Characteristics Of Terahertz Band Miniature Antenna

The terahertz waves sandwiched between microwaves and far infrared light waves, it has unique performance compared to micro-millimeter wave. Because of these properties, it was believed that terahertz technology has great research value and a good future in many different fields, such as terahertz imaging technology, biology medicine, security inspection, communication, physics, chemistry. With the rapid development of communication system, THz wave gets more and more attention, which promoted the study of the theory and applications of terahertz antenna.In this dissertation, we investigate the characteristics of terahertz antenna. The detailed work includes:1. Introducing the properties of terahertz wave and the research of the terahertz antenna at home and abroad. Some basic knowledge of antenna, the theory of the photoconductive antenna and the conductivity model of graphene were described.2. Microstrip array antennas were designed and the radiation performance of the antennas was introduced. Studying the influence of some size parameter on the antenna radiation performance and obtaining the related design patterns. In order to increase the antenna gain, we increased the number of the radiation patches. We also used the form of log-periodic antenna to increase the bandwidth of the microstrip antenna. We fabricated the microstrip array antenna and the details of the process were also presented.3. The theory of the photoconductive antenna was introduced. The design of photoconductive bowtie-shaped terahertz antennas, log-periodic terahertz antenna and equiangular spiral terahertz antenna were presented. With the help of the dielectric lens, the gain of the antenna will increase. The substrate thickness changing also will influence the antenna performance.4. The design of monolayer graphene patch antenna operating at THz band with reconfigurable capability is presented. In such Yagi-Uda type of antenna, the graphene patches are employed for achieving our desired radiation performance, which is based on tunable electrical conductivity of graphene by changing its biasing DC voltage. The adjustable range of its radiation beam at designated terahertz frequency is 180°.