| Microstrip antennas are a new type of antenna which were developed in 1970's. The emergence of wireless communication systems and radar application requires compact antennas. They are suitable for these applications compared with the standard microwave antenna because they have many advantages: high performance, thin profile, low cost.In VHF/UHF(Very High Frequency/Ultra High Frequency) ,the standard microstrip antennas of half-wave length are still very big .And the standard microstrip antenna has a very narrow bandwidth of 1～5%.So in recent years, much attention has focused on the development of broadband antennas and compact antennas. For satisfying the requirement of broadband antennas and compact antennas, we attempts to use a new design method to develop broadband antennas and compact antennas with a new type of magnetic substrate. They are useful in the domain of communication and navigation. This paper forms by two parts. The first part is the theory analysis and the experiment research of the property of the magnetic substrate. Also there are theory analysises of compact microstrip antennas and broadband microstrip antennas in this part, and we find a practical method to make certain the property of the magnetic substrate. The second part has the design,simulation and testing of circularly polarized microstrip antennas. In this part ,we decide to use the design of a square-ring microstrip antenna .And we made a receiving antenna and a transmiting antenna. |
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