Research On The Frequency Reconfigurable Antennas

The 21 st century is an information age. With the rapid development of science and technology, transmission of information by wireless has become the theme of the times. The structure of frequency reconfigurable antenna can be modified loading one or more control devices, and the antenna's operating frequency can be adjusted discretely or continuously with the movement of frequency band. At the same time, the electromagnetic interference from self or the outside world can be effectively avoided to ensure overall stability of communication. It provides a good solution for modern wireless information system. At present, the research of this area is still at the beginning, mainly in terms of numerical simulation and software from a wide range of commercial applications also require time. This paper concentrated on the problem of frequency reconfigurable antennas and some design proposals have been proposed in this work.The first frequency reconfigurable antenna is a micro-strip patch antenna prototype, using coplanar waveguide feed method. The simulation results show that the antenna may work well in DSC-1800, PCS-1900, UMTS three bands, and the pattern remains almost unchanged according to the electromagnetic simulation of the Ansoft HFSS. Next, this frequency reconfigurable micro-strip patch antenna has been improved, Then a real antenna is produced based on data, and measured using microwave vector network analyzer AV36290. Compared with the previous simulation results, the two results are consistent with coverage of the target band, each band good matching, So this kind of reconfigurable antenna is well suited for wireless communications applications.Another frequency reconfigurable antenna is a monopole antenna prototype of ultra wideband antenna, using a micro-strip line feed mode. Simulation results show that the antenna works in the band 2.45-9.88 GHz. With a clear band rejection characteristics, the overlap bands of WIMAX, WLAN can be well filtered, eliminating frequency interference between these systems and ultra-wideband systems, the radiation direction pattern remains almost unchanged. This ultra-broadband spectrum can well meet the needs of future wireless communication systems.