Design Of Monopulse Antenna Loaded With Artificial Electromagnetic Structur

Monopulse technology,also known as simultaneous multi-beam technology,is widely used in precision measurement,radar satellite tracking and other systems because of its advantages of fast acquisition and error signal and strong antiinterference ability.On the other hand,the artificial electromagnetic structure is widely used because of their unique electromagnetic characteristics.Combining it with monopulse feed can not only effectively reduce the antenna size,but also realize the high gain of monopulse antenna,further improve the aperture efficiency of monopulse antenna and greatly reduce the production cost of antenna.Based on the feed of microstrip monopulse antenna,the monopulse antenna loaded with artificial electromagnetic structure is studied deeply in this paper.The main work contents are as follows:1.An X-band monopulse antenna is proposed and designed.The microstrip slot coupled antenna is used as the radiation patch unit.After the simulation design,the absolute bandwidth of the antenna is 1.2GHz,and the relative bandwidth is 12%.We use the microstrip cross and difference network to combine the radiation patch with the feed and difference network to form a monopulse antenna.After testing,the monopulse antenna’s sum-differential port standing wave ratio is lower than 1.5,the sumdifferential port maximum gain is 10.8d Bi,the sum-differential port side lobe is lower than-15 d B,the zero-depth of sum-differential port is lower than-23 d B,a peak level of sum-differential port is less than 0.5d B,which meets the design requirements.2.Based on the monopulse feed,the artificial electromagnetic surface coating is loaded to combine the two to form a Fabry-Perot resonator.The reflection modulus value of cladding unit is 0.533.After machining and testing,the voltage standing wave ratio of the antenna is less than 2,the peak gain of the port is 14.8d Bi,and the sidelobe is less than-13 d B.The peak gain of the differential port is 12.9d Bi and 11.7d Bi respectively,the sidelobe is lower than-13 d B,the zero-depth is lower than-20 d B,and the aperture efficiency of the antenna reaches 46%.The antenna is 70mm×70mm in size and features a compact structure,small size and lightweight.3.Based on the monopulse feed,a monopulse antenna loaded with the transmission array is designed.The transmission phase shift of the designed transmission unit reaches 336.8o,and the transmission amplitude of the unit is above-1.6d B.The sum beam gain of the antenna is 21.2d Bi,and the port sidelobe is lower than-20 d B.The aperture efficiency reaches 42.1%.