Research Of Novel Radial Power Combining Technology Based On Time-symmetric Mode

As one of the key technologies for the development of high mm-wave region,power-combining technique has found important value not only in traditional military and civil applications,but also in high-speed broadband wireless communication,high resolution imaging and other roaring new applications.The combining efficient of radial-line power-combining will not obviously decrease with the increasing of combining ports number.With this characteristic,radial-line combining technique has been extensively concerned,especially in high mm-wave region.However,the radial-line combining schemes at home and abroad still follow the conventional thought in microwave band,which results in only a few available spatially symmetric modes.Therefore,the higher the operation frequency is,the more difficult in structural realization,isolation of interference mode and combining efficiency are.To address the above problem,a principle of radial time-symmetry which can solve the current situation that traditional radial power combining can only use individual spatial symmetry modes,is proposed for the first time.The mainly achievements are described as follows:Based on this principle,techniques of mode superposition are proposed to increase the available mode types in radial-line mode sets,and improve the interference mode suppression and synthesis efficiency of radial-line combiner.Then,a means of voltage vector transfer matrix analysis is proposed to accurately analyse the exciting condition of operating mode,as well as the type and isolation of interference modes.Research on novel mode conversion technique with characteristics of broadband,low loss,high power capacity,high mode purity,and strong structure realization has been carried out.In the millimeter wave band,the feasibility of the above theory,method and technology is verified.Based on the principle of radial time-symmetry,the topology of a new balanced mode transducer is researched to achieve high efficiency and high purity conversion from a standard rectangular waveguide TE₁₀ mode to a circular waveguide circularly polarized TE₁₁ mode.Then the novel balanced mode transducer is designed and verified.The back-to-back measurement results show that in the band of 88 to 102 GHz,the return loss of the mode transducer is better than 15 dB with the insertion loss less than 1.25 dB,the conversion efficiency is greater than 75%;Based on the above research results,a novel12-way power divider based on circularly polarized TE₁₁ mode is designed and simulated.The back-to-back simulation results show that from 88 to 102 GHz the return loss of the radial power combiner is better than 15 dB,the insertion loss is less than 0.5 dB,and the loss of a single combiner is less than 0.25 dB,that is,the synthesis efficiency of the combiner is greater than 94%.Finally,an E-band?71-86 GHz?12-way power combining amplifier was developed.Each branch uses a GaAs monolithic chip as a power amplifier unit,and each amplifier has a saturated output of 23.5 dBm.The measurement results show that from 71 GHz to 86 GHz,the maximum output power is greater than 33 dBm,and the maximum synthesis efficiency is greater than 80%,which realizes the characteristics of multi-way and high combining efficiency.Research results of this project have great applied value in the development of radial-line power combining theory and technique,as well as in the development and application of high frequency system.