Study On Beam-Scanning And Sidelobe Suppressed Array Antenna Based On Corporate-Fed Waveguide Network

Antenna operate as an important front-end device.Its quality directly affects the overall performance of the radio system.In the past three years,the data transmission rate of wireless transmission system has doubled every 18 months.In this trend,wireless networks will reach or even exceed the capacity of wired networks.Low-frequency spectrum resources are already very crowded and seem to have reached its highest rate.Therefore,it is necessary to develop and utilize higher frequency band resources,which is also the core problem need to be solved in the new generation of wireless communications.However,due to the high loss of high frequency electromagnetic wave in transmission,high gain and broadband antenna will be the key link to achieve high transmission rate using high frequency resources.Waveguide is one of the most coimmonly used and earliest discovered microwave transmission lines,and one of the most important guided-wave structures.The waveguide slot antenna actually based on this structure,and its characteristics are very prominent,such as minimal transmission loss,large power capacity and high aperture efficiency.These characteristics make waveguide slot arrays widely used in high frequency and high gain antennas.In this paper,the design of waveguide slot array and the application of SIW structure in waveguide slot array are studied.The main work is as follows:By discussing the recent research and development trend on the antenna field,the author illustrates the potential value of waveguide slot array antenna,beam scanning antenna and sidelobe suppressed antenna in high frequency and high gain applications.In chapter 2,firstly,the electromagnetic propagation mode in rectangular waveguide is introduced here,and the expression of the field distribution inside the waveguide and the current distribution on the surface of the waveguide are deduced.Thus we can determine the excitation forms of the slots in different positions on the surface of waveguide.Secondly,the radiation characteristics and analysis method of single waveguide slot antenna are given.Finally,array antenna theory,the design principle and general design steps of beam-scanning and sidelobe suppressed antenna are descripted.The design method of beam-scanning antenna including the beam-scanning array arrangement and the feed network design is proposed.W-band beam-scanning array antenna is designed to achieve beam scanning angles range from positive 30 degree to negative 30 degree.The radiation slot placed at the end of the waveguide is selected as element antenna for array arrangement compactness.The design method of sidelobe suppressed antenna including both array excitation determination and weighted feeding network design.Because of the limitation of air rectangular waveguide,pair excitation distribution is used instead of discrete Taylor excitation distribution.A Ku-band sidelobe suppressed antenna is simulated here to show the ability of suppressing sidelobe less than-16dB.A single-layer corporate-fed substrate integrated slot array is proposed to achieve low profile and wideband characteristics of high gain and high efficiency antenna.The full-corporate-fed circuit is realized by selecting proper dielectric substrate to narrow the width of waveguide.The 16 × 16-element slot antenna array is fabricated by the standard 3D print technology.An air-cavity layer is adopted on the top of radiating slots to boarder the reflection bandwidth.The measured results demonstrate that the proposed antenna possesses 16.2%of reflection coefficient bandwidth.Summarize the work in the paper and prospect the higher performance of full-corporate high gain broadband array antenna based on single-layer substrate integrated waveguide in the later design.