Planar Antenna Dual-band And Dual-polarized

Planar antenna, which can meet the requirements of modern wireless communication system for its low mass, small volume and easy integration with others, has been getting more and more application now. According to the demands of modern communication, an important direction of antenna research is multi-function, which means multi-band, multi-polarization and multi-purpose. So, researching on the dual band dual polarized planar antenna makes sense.From the feeding point of view, planar antenna can be divided into two parts: printed antenna and slotted-waveguide antenna. Printed antenna is widely used for its low profile, small volume, light weight and planar structure. But when operating in the high frequency, it has high dielectric loss and low radiating efficiency. Slotted-waveguide antenna is a better choice in this condition. To meet the need of the project, in this paper, a dual polarized slotted-waveguide antenna is designed in the Ku band and a dual band dual polarized microstrip antenna is implemented in the L and C bands.In the first pat of this thesis, the aim and meaning of the paper are introduced. Then, the current research and tendency in the field of dual polarized slotted-waveguide antenna and dual-frequency microstrip antenna are indicated, especially the research points and difficulties. After a brief introduction of the foundational parameters of the antenna, the basic theory of the slotted-waveguide antenna and the microstrip antenna are proposed.The third chapter of the paper takes an emphasis on the dual polarized slotted-waveguide antenna design. The process of the radiating element, linear array and planar array is presented in detail. An 8*8 equally fed slotted-waveguide array has been simulated with the aid of the finite element method tool, Ansoft'HFSS, which gives a high aperture efficiency of 70%, higher than others. Then the 10*10 array, excited by 20-dB linear Taylor aperture distribution, is successfully designed and simulated. The antenna structure has many attractive features, such as low-profile, light-weight, high-efficiency and balanced, simultaneous dual-polarization and so on. It is an ideal one for dual-frequency dual-polarization waveguide slotted antenna design.The last part of the paper proposed a multilayer dual band dual polarized (DBDP) antenna operating at L and C bands with a shared aperture. The center frequencies are about 1.25GHz and 5.3GHz, respectively. The L-band elements are selected as perforated patches to enable the placement of C-band elements within them. A subarray with one L-band element and sixteen C-band elements is fabricated and tested. The measured results indicated a reflection bandwidth about 100M based on VSWR<2. The antenna proposed here has good performance on both bands and be capable of being scaled to a large radiating aperture. It has large value in engineering application.