| A new type of VHF broadband twin-whip antenna was introduced and analyzed in this dissertation. A structure of the antenna was designed based on the theoretical analysis, and numerical simulation. The real dimension and the configuration were modified through the experiment studying. The major contributions in this paper are as follows: In some special cases the antenna has to be raised to certain height for longer distance communication. The traditional monopole whip antenna is not useful, and more because of no ground existing now. A bipolar twin-whip structure was a good choice at the moment. It has the wideband property and current balance effect. Good impedance matching networks was achieved by using LC circuit. The antenna has high radiation efficiency.A VHF broadband twin-wipe antenna prototype over 30-88MHz was made. Experimental results show that VSWR≤2.5, GAIN≥1dBi.It meets the requirements of the customer. If some losses were introduced, the antenna bandwidth can be expanded to wider range, such as 30-400MHz by adjusting LC circuit and the ratio impedance transfer.In addition, a design program of ionosphere vertical detection antenna is proposed, which used inverted V antenna structure with the matching tuner. The antenna has the advantages of simple structure and easy installation and removal. The feasibility of the antenna is verified through the numerical simulation and scale model test. |
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