Research On The Miniaturized UWB Microstrip Antenna

As the development of Micro-strip integration technology and Space technology, low-profile antenna is on the urgent needs. Micro-strip antennas are paid a wide range of attention and research because of its many advantages. Meanwhile, as one of an improved wireless communication, the UWB technology is widely used in Radar, Positioning System, Electronic Countermeasures and Secure Communication area, and strictly protected by the military all over the country as the top classified technology. In recent years, the UWB wireless communication technologies is opened to the personal application area. Since then, this technology had been becoming more and more important in our daily life.This paper is mainly focused on the miniaturized, ultra-wideband and band-notched antenna. Firstly, the research statues of UWB antenna and miniaturized antenna are briefly introduced. Then the fundamental knowledge and the main characteristic parameters of antenna are introduced. The working principle of a simple rectangular micro-strip antenna is discussed in this paper, and then the three methods to analyze a micro-strip antenna theoretically is also discussed and compared among them. In the third chapter, the UWB technology characteristic, developed and used statues in present day are introduced. Then some fundamental structures of UWB antenna are introduced and discussed. Further more, some other structures of UWB antenna proposed in recent years are discussed and briefly analyzed. In the forth chapter, a novel UWB micro-strip-fed antenna with L-shape ground is designed, and three most key parameters are analyzed and discussed. Simulated results indicate that good impendence bandwidth is obtained. In the last, a small Ultra-wideband Band-Notched monopole antenna for USB wireless applications is designed and analyzed. To reduce the interface with WLAN system, a fork-shape structure is added in this antenna. This antenna was fabricated and the simulation results have been verified by comparing with measurements. Due to its creative structure, this antenna can be widely used in USB wireless ultra-wideband communication system.The two following aspects of work are included in this dissertation:Firstly, a novel UWB micro-strip-fed antenna with L-shape ground is proposed. With the L-shape ground, the current path length is improved, so the impendence performance in lower frequency is became better. Then a notch is added in the ground, under the micro-strip line, to make the impendence performance in higher frequency better. The simulation results show the impendence bandwidth is fulfilled the UWB rule, and the radiation performance is Omni-directional in certain frequency band. Secondly, a small Ultra-wideband Band-Notched monopole antenna for wireless USB applications is proposed, and With a aperture type patch, the antenna has characteristic of UWB, and two U-shape folding patch are added to cause a band-notched performance as to reduce the interface in5GHz band with other systems. This antenna has a simple structure, small size and low profile to make. Meanwhile, the ground of the antenna can be used as the PCB circuit ground. The designed antenna is fabricated, the test and simulation results showed the impendence performance fulfilled the UWB request, and had the band-notched around5GHz.