The Study Of Broadband And Miniaturized High-performance Whip Antenna

The application of whip antennas in HF communication is more and more wide.The miniaturization and broadband are an inevitable trend. This thesis is based on Finite-difference Time-domain(FDTD) method, and the design of broadband and miniaturized high-performance whip antenna is researched. The thin-wire approximate model of the whip antenna is presented and the equivalent voltage source is introduced. A loaded whip antenna and its matching network are analyzed and optimized. In this thesis, when the antenna is designed, the gain, bandwidth and efficiency are taken into account, and Genetic Algorithm(GA) is used to optimize the high performance antenna. The research work of the whip antenna is listed.1. Starting from the basic principle of the electromagnetic field, Maxwell’s curl equations are differenced, and the FDTD method in the polar coordinates is used to simulate antennas. The semi-analytical and semi-numerical thin-wire approximation is applied to the near fields around the antenna, which improves computational efficiency. An equivalent voltage source is introduced to reduce the computational space. Then the lumped element FDTD format is introduced, and the FDTD simulation is realized. Resistively loaded antennas and capacitively loaded antennas are analyzed with this method. 2. The integrated technology is used,with the loaded element and matching network. Taking into account the properties of GA, the joint of FDTD and GA simulation is realized, and the loaded element values and location are optimized. Lumped loading improves the antenna radiation situation to some extent, but it does not expand the bandwidth very well. The bandwidth, efficiency and other factors are considered, and then the matching network is optimized. Finally, a broadband and miniaturized high-performance whip antenna is optimized and designed.