Wide-band horn antennas of low profile

With the rapid development of ultra-wideband technology and with the advantages of high capacity, large bandwidth, and high speed, ultra-wideband antennas have been widely used in fields such as electromagnetic compatibility, electromagnetic measurement, and ultra-wideband radar. Horn antennas have been used in many ultra-wideband systems due to their good gain, directivity, and simple structure. To solve the disadvantages of traditional horn antennas such as high profile, and to enable the horn antenna to obtain a wider operating bandwidth, a ridged horn antenna formed by adding a ridge structure inside the traditional horn antenna was proposed. The capacitive effect caused by the existence of the ridge expands the single-mode operating bandwidth of the horn antenna. This thesis first discusses the development of ultra-wideband antennas and introduces the basic theories of antennas and ridge waveguides. Second, an ultra-wideband ridged horn antenna is designed on this basis. Simulated results show that the designed antenna has good radiation characteristics over the frequency band from 1 to 5 GHz. Its VSWR is less than 2.5 and its gain is acceptable in the frequency band. Based on the designed horn antenna, a low-profile H-plane ridged horn antenna placed on a metallic surface is finally described. This H-plane horn antenna can be used in practical applications such as UAV.Master of Science (Communications Engineering