Study On Ridge Substrate Integrated Waveguide Slot Array Antenna And Feed Network

With the development of communication system to microwave and millimeter wave band,the traditional metal waveguide is difficult to connect with other planar structures due to its large size and high processing cost.Therefore,the planarization of waveguide has become the focus of many scholars.Substrate integrated waveguides(SIW)have been widely used for their advantages of combining traditional rectangular waveguides and planar circuits.After that,the ridge substrate integrated waveguide(RSIW)structure was proposed.In comparison,it has wider single-mode operating bandwidth,smaller equivalent impedance and smaller size with the same frequency.The research of passive devices and antennas based on RSIW structure has become one of the hot spots nowadays.In this thesis,a broadband RSIW structure has been designed by comparing the single-mode bandwidth among different ridges,which is suitable for processing.Meanwhile,the transition from RSIW to micro-strip has been designed for X-band,including the measurement framework.After that,an 8-way unequal power divider,a linear polarization slot array antenna and a circular polarization slot array antenna are designed based on RSIW for low sidelobe and cross-polarization.The detailed research as follows:1? The theory and analysis of RSIW basis on ridge waveguide and SIW,including its measurement framework and balun to micro-strip.Then,a design process of RSIW has been designed by comparing different ridge,which is broadband and suitable for processing.Meanwhile,the balun to micro-strip is been designed for integrated with other planar circuits.Finally,a measurement framework of coaxial-microstrip-structure microstrip-coaxial is designed,which is easy to be measured uniformly.2? The design of 8-way unequal power divider based on RSIW.In this section,the waveguide branch of H-T and right angle are applied to the design of power divider and some modifications were adopted.The specific power ratio is achieved by adding inductive metal post at different positions of the branches and adjusting the matching of input port.At the same time,a phase-shifting segment is added to the branch with backward phase to ensure that the output ports is in the same phase.Then,the 2-way,4-way and 8-way unequal power dividers were designed as 9GHz in the x-band respectively,and the output amplitude of 8-way power dividers varied according to the amplitude distribution obtained by the low sidelobe synthesis.3? Low sidelobe linear polarization slot array antenna.In this section,the admittance characteristics of a single longitudinal slot on the broad wall of the RSIW are studied to verify its consistency with the waveguide slot.Then,in the design of slot array antenna based on RSIW,the experimental simulation method is used to estimate the coupling between the slots.Finally,8-element linear array and 8×8 plane array are designed respectively in the x-frequency band,with the center frequency of 9GHz.The low sidelobe characteristics are realized simultaneously on plane E and plane H by using the feed network of the previously designed 8-way unequal division power divider.4? Low sidelobe circular polarization slot array antenna.In this section,the circular polarization radiation is realized by loading a planar parasitic dipole on a linear slot array antenna with low sidelobe.In order to take the influence of coupling among the elements into account,the position and size of the parasitic dipole are determined by considering coupling.Then,an 8-element circular polarization linear array based on RSIW is presented.The simulation results show that the axial ratio of the antenna meets the requirements,and the low sidelobe characteristics are realized in the plane where the maximum radiation direction and array direction are located.