Research On Planar Microwave Power Synthesis Technology

In the field of radio frequency and microwave,power dividers,also known as power splitters,have played an important role for many years.The main function of a power divider is to split a given input signal into two or more signals according to the needs of the circuit/system.A typical application for a power divider is to distribute the signal to multiple low power amplifiers,amplify the power with the amplifiers and then recombine the signal that comes from each amplifiers into a high power output signal.Although the ideal(matched,isolated,lossless)power divider is not physically achievable,however,better results can be obtained by optimising the design of the circuit.With the development of microwave technology,power dividers with high withstand power,low reflection loss,low transmission loss and high isolation have promising prospects,which can be used in electronic reconnaissance equipment or electronic interference equipment,also in broadband test equipment such as civil/military EMC laboratories,military RCS laboratories or antenna darkrooms,and in radio frequency equipment of radio and television stations and satellite earth stations.The planar power combining circuit is easy to integrate with other circuits,the manufacturing process is simple,and it is easier to implement,but the disadvantage is that the parameter index is slightly lower than that of other structures,which limits its use in engineering.In order to better study the application of power dividers,the following results were made in this paper.(1)Aiming at the engineering application of the 500MHz-6GHz frequency band,a multi-layer board structure with a wide-bandwidth high-power low-loss 3d B 90° bridge is proposed,design based on the combination of the structural characteristics of the embedded3 d B 90° bridge and the chip-type 3d B 90° bridge.It has a 4-layer PCB structure,including the upper,middle and lower 3 PCBs and 2-layer prepregs,input ports,isolation ports,pass-through ports,exchange ports and 3d B changeovers are all on the middle PCB,and all4 ports are integrated in the same plane by drilling and plating.Broadband,high-power,low-loss 3d B 90° electric bridge has the advantages of large withstand power and low loss.The operating frequency is at 800MHz?6GHz,the withstand power is above 300 W,the port standing wave ratio is less than 1.4,the isolation is greater than 18.5d B,back-to-back measured one-side insertion loss is less than or equal to 1d B,which meets the needs of the two-way synthesis of the power amplifier.(2)Aiming at the shortcomings of poor matching of conventional multi-sections,matching fan-shaped appointments is coordinated,and a high-index multi-branch electric bridge is proposed.Based on the traditional design method of multi-branch electric bridge,the study focus on the influence of fan-shaped matching branch on the multi-branch electric bridge.On the final designed three-branch electric bridge,the measured port standing wave ratio is less than 1.25,and the isolation is greater than 15 d B.This three-branch electric bridge has the characteristics of wide frequency band and low loss,and the output port is on the same side of the device,which can be integrated with other subsequent semiconductor devices to form an integrated circuit.(3)Aiming at the shortcomings of traditional microstrip line structure and waveguide structure power divider of large size,difficult to integrate,and poor power processing capability,a Gysel power divider based on ridge waveguide is proposed.In the situation of the malfunction caused by the power imbalance between the inputs,the terminal load of the Gysel circuit can withstand greater errors.The working frequency of the power splitter is at1.4 GHz-4.2 GHz,the return loss of the input and output ports is below-20 d B,and the fluctuation is small,and the isolation of the whole frequency band is below-21 d B,considering the processing error and uneven materials in the actual production,each indicator has a certain margin range,and subsequent physical production is more feasible.