Research On Microwave And Millimeter Wave Ultra-wideband Power Dividing And Combining Network And Their Application

Microwave and millimeter Power dividing network is a kind of important passive networks which are widely applied in power combining sources and various phased array systems.With the increase of the bandwidth and output power of various microwave and millimeter wave application systems such as radar and communications,the technical demand for microwave and millimeter wave ultra-wideband high-performance power dividing/ combining network is also increasing.Based on such background,an in-depth study has been carried in this paper on the design and realization of planar ultra-wideband multi-channel power dividing/combining network,waveguide-based ultra-wideband power dividing/combining network and related matching loads with high power in millimeter wave region.The main achievements are as follows:1.An eight-channel power diviging/combining network based on planar microstrip circuit has been developed for an ultra-wide band application over 6?14GHz.In order to meet the requirements of the ultra-wide working bandwidth and the isolation between channels,a design scheme is worked out for the ultra-wideband multi-channel power divider / combiner network,which is based on Wilkinson power divider with two-stage impedance transformation line as the basic unit of the eight-channel power divider network.A Simulation model has been established with Ansoft HFSS for the ultra-wideband 8-channel power divider / combiner network.Aiming at overcoming the influence of cavity resonance on the performance of power divider,the lowest resonant frequency is moved out of the working frequency band and the isolation between the output ports is strengthened by designing the shielding cavity in the form of channels.Based on the optimization results,a 6?14GHz ultra-wideband 8-channel Wilkinson power divider / combiner network is developed.The test results show that the return loss of each channel is better than 10 dB,the typical insertion loss of each channel is 10 dB,the amplitude inconsistency between the channels is better than 0.25 dB,the phase inconsistency is better than 2.5 °,and the isolation between the output ports is better than 20 dB in the frequency band of 6 ? 14 GHz.2.In order to realize the ultra-wideband,high-isolation and low-profile waveguide power divider / combiner network,the bandwidth expansion technology of waveguide quasi-coplanar magic T power divider / synthesizer network with microstrip probe absorption port is studied in depth.A prototype of the ultra-wideband quasi-coplanar waveguide power divider / synthesizer network with working frequency band of 25.0 ? 42.0 GHz is successfully developed.In order to achieve good isolation and port matching performance,a waveguide microstrip probe is inserted into the center of the E-plane in the traditional E-plane T-junction common waveguide.A matching load is loaded at the end of the microstrip line.The unbalanced energy in the waveguide T-junction is coupled to the microstrip line by the probe,and then transmitted to the matching load at the end to be absorbed.In this way,the function of isolation port of traditional magic T is realized.With the help of HFSS software,the influence of the error between the probe area window width and the resistance value on the port matching,insertion loss and isolation of the power divider is investigated.Based on the results of the optimized parameters,an ultra-wideband quasi-coplanar waveguide power divider / combiner network is fabricated.The test results show that the typical insertion loss is 3.34 dB(additional insertion loss is 0.34 dB)in the 25.0 ? 42.0 GHz band,the amplitude imbalance of the two channels is better than 0.1 dB,and the isolation between the output ports is better than 10 dB.The typical value of insertion loss is 1dB when two identical power divider samples are connected back to back.3.In order to realize the broadband,high isolation and good port matching waveguide power divider / combiner network,the high-isolation waveguide Y-type power divider and wideband and high-isolation three-way power divider are developed based on the TaN film and waveguide coupler respectively.In order to improve the isolation of the traditional waveguide Y-type power divider,an alumina ceramic substrate coated with the TaN film on both sides is inserted in the center of the common waveguide H-plane.In order to achieve the same amplitude and phase output of E-band three-channel power divider,the feed-through ends of two branch waveguide couplers with identical structure are combined in to one port,and a 90° wideband phase shifter is inserted in the common feed-through end.The experimental samples of the E-band high-isolation waveguide Y-type power divider and the E band high-isolation three-way power divider are fabricated and tested based on the analysis and iteration of key parameters.Measured results show that,for the E-band high-isolation waveguide Y-type power divider in the 71-78 GHz frequency band,the typical insertion loss is 3.5dB,the amplitude imbalance is better than 0.13 dB and the isolation is better than10 dB.For the E-band wideband high-solation three-way power divider,the typical values of insertion loss at coupling end and through end are 5dB and 5.45 dB respectively,the unbalance of amplitude is better than 0.75 dB and the unbalance of phase is better than 5 °,the isolation between the three output ports is more than 19 dB in the 70-78 GHz frequency band.4.In order to meet the test requirements of E-band high-power output solid-state power source,an E band high-power matching load has been developed based on TaN film.In order to meet the requirements of power capacity,the design scheme of improving the power absorption capacity of the absorber and power split is adopted,a 4-way waveguide Y-type power synthesis network is used to combine 4 improved waveguide matching loads into a high power matching load.The microwave performance and heat dissipation characteristics of the matched load have been modeled and analyzed with the Ansoft HFSS and Solid Works 2014 respectively.An experimental sample is processed and tested to verify performance of the E band matched load.The test results show that the return loss is below 20 dB,the VSWR is better than 1.3 during the operating frequency range and the power capacity is more than 5W under the condition of ambient temperature of room temperature and natural convection,which meets the index requirements.