| Along with scientific research and the demand of practical engineering, this dissertation focuses on the VHF omnidirectional broadband antenna and anti-jamming array system. The author’s major contributions are outlined as follows:1. Research on VHF broadband high-power antenna for emergency communication. On account of the communication demand, technologies and solutions to achieve efficient and broadband performance for the VHF antenna are studied under the condition of high power. Two VHF antennas with different polarization are designed. First of all, the horizontally polarized antenna adopts the form of ring antenna, and by modifying antenna structure, the impedance bandwidth of the dipole has been broaden. Two different cases of antenna element and its array have been studied, for the different demands of vehicle terminal and fixed station. The simulated relative bandwidth reaches about 30% for the antenna element. Secondly, the antenna with vertical polarization is designed in the form of printed dipole. By employing a novel electromagnetically coupled method, the antenna proposed in this paper realizes the broadband and efficient performance and an operating bandwidth of 34%.2. Research on VHF omnidirectional broadband antenna for vehicle termination. Broadband technologies are studied for the monopole antenna. Adopting monopole structure, the antenna radiator is designed with lossless load, and combined with broadband matching network. Loading slots and broadband matching network, the proposed antenna achieves the broadband characteristic. Additionally, the patch antenna is manufactured together with aircraft’s skin. Note that effects of the aircraft structure on the radiation features of the antenna have been studied, and multiple methods, such as modifying the structure of the patch, integrating with gaps, have been adopted to improve the antenna characteristics. The test results are in good agreement with the simulated ones.3. Research on integrated VHF antenna. For the requirement of VHF dual system, two integrated VHF antennas with dual-band and the same frequency are studied and designed, combined with miniaturization and broadband technologies. First, based on pyramid with gradual change and top loading, the dual-band integrated antenna with two-port has been studied, which achieves wideband, miniaturization and good isolation between the antenna elements. Second, to weaken the dependence of the ground on the radiation feature of the antenna, a two-port printed dipole antenna working in the same band has been designed and miniaturized, using techniques such as matching branches of open circuit. Two prototypes have been fabricated and the measured results show that all requirements are satisfied such as the VSWR, un-roundness in the horizontal plane and horizontal gain. The measured results are in good agreement with the simulated results. 4. Research on VHF anti-jamming array. The VHF broadband array antenna is studied in three parts. The element of the array has been studied firstly. After comparing electrical performance among low profile antenna, biconical antenna, and sleeve antenna, a dual-sleeve antenna is finally selected to be an element of the array, and it has been optimized to achieve miniaturization further. Secondly, the effects of mutual coupling between the elements on radiation pattern and VSWR features have been studied in the array. Finally, using Genetic algorithm to shape the beam for the loop array, the array antenna achieves 360°beam coverage in the horizontal plane, over 9 d B of gain for the main beam, and less than-11 d B of sidelobe. For requirement of anti-jamming, zero algorithm of anti-jamming is investigated to shape depression of pattern on condition that the main beam points to the direction of the desired user signal.
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