Research On Radiation And Scattering Characteristics Of Microstrip Antenna

With the rapid development and maturation of wireless communication technology,the degree of integration and miniaturization of communication systems is getting higher and higher.Microstrip antennas are commonly used on high-speed aircraft because of their light weight and small size,as well as their easy conformity and integration.For the sake of system integration and miniaturization,the problem of harmonic suppression of microstrip antennas needs to be studied to prevent electromagnetic interference;on the other hand,for the sake of radar stealth of aircrafts,the problem of radar cross section reduction of microstrip antennas also should be studied,which enhances the stealth characteristics while ensuring the radiation and reception of the antenna.This thesis focuses on the study of harmonic suppression and scattering reduction for microstrip antennas,the main work is as follows:1.Two kinds of complementary split ring resonator(CSRR)structures are combined in a particular way and the combined structure is loaded onto the ground under the feedline of the microstrip patch antenna,which the higher harmonics of the microstrip antenna can be suppressed.The two CSRR structures have different stop bands,and the combination of the two structures can also lead to a new stop band.The above stop band correspond to the harmonics of the antenna and multi-band harmonic suppression is achieved.The introduction of the CSRR structure does not substantially affect the operating frequency band of the antenna.2.A polarization conversion unit with a quasi-fractal structure is proposed.The unit has a high polarization conversion rate.Using the reflection mechanism of the polarization conversion metamaterial,the unit and the mirror unit are combined to construct a low radar cross section(RCS)of the checkerboard structure.The proposed meta-surface has a scattering reduction of 5 dB and above in the 24GHz-30GHz and 41GHz-60GHz frequency bands compared to the perfect electrical conductor.3.The designed polarization conversion meta-surface is loaded around the radiating patch of the microstrip antenna to realize the reduction of the RCS of the microstrip antenna in the high frequency band.The frequency band of RCS reduction is 20GHz-60 GHz,and the radiation performance of the antenna is kept well.