A Study On Miniaturization And Ultra Wideband Of The Microstrip Antenna

Now ultra wideband technology is the first choice of the short-range wireless communication, meanwhile, as the key device for Ultra Wideband system, the performance of the antenna affects the communication quality directly. Microstrip antenna has so many characteristics, such as inexpensive in price, small in size, light in weight, and easy to be integrated with an RF circuit and so on, that more and more people pay attention on it. In effect, the electromagnetic coupling between antennas is inevitable, and that will affect the performance of antenna array directly. People are urgent to find some effective methods to enhance the insulation between the units. Based on the reasons above, this paper focuses on the research of the ultra wideband microstrip antenna array with high isolation.In this paper, we have designed and studied two kinds of the Ultra Wideband microstrip antenna array with high isolation. The work is divided into two parts: the first part, we have designed an ultra wideband microstrip antenna with high isolation placed in parallel; the second part, we have designed a double frequency band-notched ultra wideband microstrip antenna with high isolation placed in orthogonal. The specific contents are as follows:1. The design is a placed horizontally ultra wideband microstrip antenna with coplanar waveguide fed. By using a three-layer structure and adding two narrow stubs connecting antenna and the floor, it realizes the characteristics of high isolation. The simulation results by HFSS shows that the frequency band(VSWR is less than 2) is 2.8 GHz ~19 GHz and it has realized the Ultra Wideband characteristics. The transmission function 21 between the units is less than-20 d B and in the whole frequency band, it has realized high isolation characteristics. At the same time, the antenna has fine radiation characteristics in the whole work frequency band.2. The design is a placed vertically ultra wideband microstrip antenna with coplanar waveguide fed. By adjusting the location of the two units, it realizes the characteristics of high isolation. By notching on the antennas, it realizes the characteristics of frequency band-notched. The simulation results by HFSS shows that the frequency band(VSWR is less than 2) is 3.1 GHz~12 GHz and it has realized the UltraWideband characteristics. The NO.1 antenna is frequency band notched in 5.1 GHz~6.1 GHz, and the NO.2 antenna is frequency band notched in 6.7 GHz~7.8 GHz. The transmission function 21 between the units is less than-20 d B and in the whole frequency band, it has realized high isolation characteristics. By measuring, the antenna satisfy the design targets.