Cone Beam Antenna Design

Conical beam antennas (CBAs)are one of the best choice for satellite mobile communication and wireless local area network. However, it is very difficult to realize a large beam inclination and a high gain, meanwhile the feed networks are usually complicated. In this thesis, two kinds of CBAs are investigated at different operating frequency to achieve a large beam angle. The first one is quasi-planar conical beam antenna consisting a circular waveguide with polycyclic slot structure to controlling circular waveguide modes, which has the advantages of simple feed, low loss, and band width. Another is a coaxial CTS array with conical beam, which has the advantages of broad band width, high gain, simple feed, and ease of fabrication.Firstly, the definition and application background of CBAs is interpreted. Research progress at domestic and overseas are summarized for planar conical beam antennas and CTS antennas with conical beams.Secondly, the design principle of quasi-planar conical beam antenna with polycyclic slot structure to controlling circular waveguide modes is given in the paper, and through the selection of circular waveguide modes, determines incentive model, and optimizes the overall antenna through model matching method and electromagnetic simulation software; and designs a quasi-planar conical beam antenna operating at35GHz to realize the40degrees beam angle. By simulation we can know, a impedance bandwidth of20%in terms of reflection less than-10dB, a gain of7.2dBi at operating frequency, and3dB beam width is27degrees,and the side lobe level is less than-10dB.Finally, through an in-depth study on the radiation characteristics of coaxial CTS element; introduces coaxial CTS element simulation model with periodic boundary in the paper, and performs a parametric study on element structure, and gives optimization and design basis of coaxial CTS elements of different radiation energy, and gives elements cascaded analysis and array spacing formula of linear array, and designs coaxial CTS conical beam antenna operating at12.5GHz to realize55degrees beam angle in the paper,。 By measurement we can know, the impedance bandwidth of26%in terms of reflection less than-10dB, a gain of9.4dBi at the central frequency12.5GHz, and3dB beam width is13.8degrees, and the side lobe level is less than-10dB, and the measured results and simulation results are in good agreement.In the paper, the two kinds of conical beam antennas can realize big beam angle and high gain, and have great value in engineering application.