| Television, the greatest harvest of human wisdom in 20th century.affects people's life style in abundant and vivid way and becomes the indispensable modern science and technology. We have a claim for high standards for the key performance index, especially the low VSWR and wide bandwidth. It is a challenge to realize these performance index. Lower VSWR can make the TV picture sharper and eliminate fuzzy or ghost image. Wider bandwidth can increase the number of TV channel by raising the utilization rate of antennas.In this paper, a novel dual-loop antenna is presented and investigated. It meets the requirement of transmitting antenna because of appealing features, such as wide impedance band-width, lower VSWR, high gain, good omni-directional radiation pattern.simple structure, low cost, etc.In this article, after the research of the principle of loop antennas and the theoretical analysis of the duplex dual-loop antenna, a shielded loop antenna is proposed to be used as an elementary antenna of the duplex dual-loop antenna. The dual compensation plays a good role in improving the narrow band and the VSWR. We can optimize the parameters of the proposed antenna by simulation and measurement. Finally the good characteristics of TV transmitting antennas are obtained. The measured results show that the proposed antenna meets the requirement of wide-working band-width of 30MHzwith VSWR<1.2, good radiation pattern is obtained and the gain of the antenna is 4.1 dBi.So it lays a solid foundation for the design of similar antennas. |
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