The Design Of Cavity Sector Antenna

Point-to-multipoint microwave communication system is one of the main application scenarios of sector antenna.Compared with the communication antenna of terminal station,HUB station has higher requirements on the antenna it used,especially on its radiation pattern,which is closely related to the network planning and anti-interference requirements.The technical standard of sector antenna specifies the minimum gain,HPBW,RPE and other parameters.By analyzing these parameters,the design index of sector antenna is formulated.Based on the basic principle of horn antenna and the near-far field transformation theory of sector antenna,this paper designs two wide-beam sector antennas with central frequency of 27 GHz and 10 GHz respectively,as well as two narrow-beam sector antennas with the same frequency.The wide beam sector antenna is composed of two main components,radiating cavity and special-shaped choke slots.The radiating cavity is redesigned to realize the fan-shaped beam with the beam-width of 90° through the research and calculation of the optimal basic size of it.In order to effectively improve the RPE,F/B Ratio and other key indicators of the antenna,based on the idea of derived radiation generated by the surface current of the special-shaped choke slots,the choke slots are added on both sides of the radiating cavity aperture,so that the design of the sector antenna can meet the design indexes.The design of narrow beam sector antenna is slightly different from the wide beam one.Because the design of wide beam radiating cavity cannot achieve narrow beam directly,the antenna uses the design method of two combined shaped horn with different angles.The horizontal beam width is initially reduced to 40°-60°by the first section called radiating cavity structure.Inner wall shaping grooves are used in the second section called shaped horn structure to improve the side and back lobe level of antenna pattern,and the horizontal beam width is adjusted to 30° to meet the ETSI SS1 RPE level required by the design index.In this paper,the validation of 27 GHz wide beam and narrow beam antennas with higher frequency and higher precision are carried out,and the feasibility of this design method is verified.The main research work of this paper is as follows: 1.Research the technical standard of sector antenna and make the design index;2.The theoretical basis of fan-shaped beam antenna is introduced;3.Research and validation of wide beam sector antenna;4.Research and validation of narrow beam sector antenna.