Research And Design Of Multi-port Filter Power Division Circuit Based On SIW

As an important part of modern wireless communication systems,the power divider is an indispensable device for signal power division and combination.In modern wireless and mobile communication systems,the miniaturization of RF microwave circuits are in great demands,which requires us to integrate different functions into the power divider to effectively reduce the circuit size and the noise caused by multi-device connection.In traditional RF circuits,power dividers and filters are usually designed and manufactured separately.The filtering power divider is widely used in power division networks and feeding systems because of its combination of filtering characteristic and power distribution.In feeding systems,in order to improve the polarization purity of circularly polarized antennas,sequential-phase feeding networks are widely used in addition to the conventional power divider feeding network.In this paper,the substrate integrated waveguide（SIW）resonator structure is used to study and design the filtering power divider with isolation performance and sequential-phase feeding network.The main research work is as follows:1.A Ka-band filtering power divider with high-isolation based on SIW:The design method for Ka-band filtering power dividers with extremely high isolation is proposed.In order to improve the isolation of the outputs,the resonant cavities of two outputs are coupled to the same resonant cavity which works at mode TE₂₀₁,and the high isolation function is realized by the cancellation of the electromagnetic characteristics of the TE₂₀₁mode.2.A unequal SIW filtering power divider based on Wilkinson structure:A design method for SIW filtering unequal power dividers based on Wilkinson power divider structure is proposed.The multi-stage half-mode substrate integrated waveguide（HMSIW）coupled filter is used as the load of the Wilkinson unequal power divider,which not only realizes the impedance transformer,but also improves the circuit selection characteristics.Isolation of the output ports is achieved by using an isolation resistor connected between the HMISW resonators.3.A sequential-phase feeding network based on SIW:A design method for sequential-phase feeding network based on SIW is proposed,which consists of SIW resonators and two quarter-wavelength SIW transmission lines.The resonant mode TE₂₀₁ provides 180°phase difference and the quarter-wavelength SIW transmission line achieves 90°phase difference.The designed feeding network has four output ports with equal amplitudes and phases of 0°,90°,180°,and 270° respectively.