Research On Broadband Conformal Antenna

Because of the advantages of low profile, light weight and easy integration, the conformal antenna has been widely used in the fields of aeronautics, astronautics and guided navigation. Without destroying the mechanical structure and mechanical strength of the aircraft surface, the conformal antenna usually attached to the aircraft surface can achieve the goal of wide-angle scanning and omni-directional coverage. So the aircraft with the conformal antenna can still maintain good aerodynamic performance when high flying speed. Because of these merits, the conformal antenna has become a hot research topic. Based on the existing research achievements, much work has been done in this thesis. Several kinds of broadband conformal antennas with good performance are proposed, which have some practical value.The main achievement of this thesis is summarized as follows:1. Research status of conformal antenna is summarized. The basic theory of conformal antenna is introduced. Some crucial problems of conformal antenna are discussed. The wideband enhancement technology of low-profile microstrip antenna is introduced.2. A practical broadband conformal parasitic patch antenna is proposed and designed. It covers aviation radio navigation frequency band (5GHz～5.15GHz,5.15GHz～5.25GHz and 5.35GHz～5.46GHz). On this basis, by changing the location of the parasitic patches, another new kind of antenna is proposed. It has a smaller size (about 70% of the first structure) and improved radiation pattern. The two kinds of antennas are fabricated and measured. The measured results are in well agreement with the simulated results.3. An electromagnetic coupling conformal microstrip log-periodic antenna is designed. Its frequency band ranges from 4.4GHz to 10GHz. This antenna is fabricated and measured. The measured results are consistent with the simulated results.4. Considering the above conformal microstrip log-periodic antenna has a bad radiation pattern at high frequency (above 10GHz), a trapezoidal conformal microstrip log-periodic antenna is proposed and simulated. The simulated results show that this antenna improves the high-frequency radiation characteristics and has a wider bandwidth (4.4GHz～12GHz).