Research On Shaped Printed Arrays And Meteor Burst Communication Antennas

Printed antennas have been applied widely in many areas such as Radar and communication because of their own advantages. To meet different and practical needs, antennas are required to realize different shaped beams, at the same time, the compact structure and light weight of the array are also desired. Consequently, the research on compact and light shaped array antennas with hign performances are of great importance.In addition, as a guarantee means of emergency communication, the Meteor Burst Communication (MBC) are attached more and more importance because it can provide the final communication guarantee. The research on the appropriate antenna is the basis of founding the independent MBC system.Being associated with three research projects, this dissertation makes deeply insight to the printed array antennas and the MBC antennas. The author's major contributions are as follows:1.The synthesis method which is suitable for the low side-lobe and shaped printed array antenna is given. The Taylor synthesis and the Method of Least Squares are separately applied in the design of the azimuth low side-lobe pattern and the elevation csc 2θshaped beam. The main parameters of antenna such as the element number and space can be determined, which is the basis of the precise beam design.2. The iterative Taylor synthesis based on the amplitude and phase errors model is studied, which is appropriate for the design of the low side-lobe beam. This method premeditates effects of the errors on the sidelobe level of the pattern on the basis of the statistic characteristics of errors. Consequently, the application of this method ensure that the sidelobe level satisfy the requirement on the condition of the practical fabrication and installation.3. The symmetrically and implicitly constrained nonlinear optimization method of the shaped beam is presented, which is suitable for the design of csc 2θshaped beam. On the condition of satisfying the object beam, the symmetric and implicit constraint on the amplitude of current can not only halve the design of feeding network, but also decrease the amplitude ratio of adjacent elements. Consequently make it simple to be printed and increase the power capacity of the network. Furthermore, the implicitly constrained method transforms the constrained optimization to the non-constrained, therefore the optimization difficulty decreases and the efficiency is improved.4. A new microstrip/strip hybrid feeding network with double layers is given. In the former stage of this network, the air strip with double layers is used in the advantages of its low loss, great power capacity and compact structure, etc. In the latter stage, the microstrip line is adopted mainly because it can be integrated with the radiation dipoles easily. Thus, the hybrid network in this paper is not only easy to integrated, but also compact and light, which is of great importance in the miniaturization design of the antenna feeding system.5. The cascaded analysis method of scattering matrix suitable for large and complicate feeding system is studied. After dividing the whole network into several sub-networks, its performances can be obtained by cascading the partial scattering matrix. Moreover, the hybrid structure of radiation elements and network can be analyzed. Therefore, this method breaks through the limit of computer resources, and improves the computer efficiency and precision. The measured results show that the printed antenna meets all the requirements such as VSWR, low side-lobe and shaped beam.6. A printed dipole array antenna with series feed for the UHF vehicle loaded mobile communication is presented, which can satisfy the requirement of omni-directional pattern in the azimuth plane and the shaped pattern in the elevation plane. Moreover, the miniaturization of the antenna is obtained because the application of series feed of parallel strip. The rapid optimization method of the elevation shaped beam which using the GA and MoM is given and the effects of the element space on the radiation pattern are analyzed. The measured results show the validity of the design.7. Based on the research of the MBC mechanism, the optimization method of the Yagi-Uda antenna fit for the MBC is studied. The parameter design and multi-objective optimization process of the VHF Yagi-Uda antenna are given. The experimental antenna is integrated with the MBC system and the link communication experiment is successfully made between Xi'an and Bazhou.8.According to the MBC requirement of antenna pattern, the design and optimization method of improved Yagi-Uda antenna and Yagi-Uda array antenna is given. The wide-band Yagi-Uda antenna with an x-shape driven dipole is presented and the measured results are given. The vertically stacked Yagi-Uda antenna array and the multi-receiver/multi-beam antenna system are studied to improve the antenna gain on the condition that keeping the wide horizontal HPBW. The simulated results show that the antenna gain can improve 2.6dB and 5.2dB respectively. The research of the wide-band Yagi-Uda antenna for the MBC can provide important reference to the improvement of the system performance.