Research On Multi - Channel Broadband Millimeter Wave Space Power Synthesizer Based On Waveguide

With the rapid development of radars and communication technology, great power,wide passband and high frequency characteristics are requested for power amplifiers. But inthe high-frequency, the output power of single amplifier chip is not enough for industryapplication. In order to solve this problem effectively, power combination techniques arewidely used. There are two kinds of millimeter wave spatial power combiners presented inthis context. The simulation and measurement proves that these two structures are feasible.The major achievements are list as the followings:(1)A novel twenty-way radial waveguide spatial power combiner is designed. Firstly,the distribution of the electromagnetic field inside the radial waveguide is analyzed. Then,the transition structure of radial waveguide and waveguide-microstrip probe are simulated.Finally, thermal design and processing technology are developed. Measured results showthat output power reaches40dBm, gain is above13dB, meeting the requirements.(2)In order to improve the performance of the structure, a new structure of gradualridge is applied in each branch circuit of radial waveguide. Simulation results show that theS-parameters of the combiner have been greatly improved after adding the gradual ridge.And the passband has been effectively widened.(3)A sixteen-way chain waveguide spatial power combiner is designed. First thestructure is divided into two parts from a standard waveguide, each branch waveguide istransformed gradually to become standard waveguide port, and then they are dividedequally by chain waveguide, at last the16-way combiner structure is formed. Due to thehigh frequency, small size and relatively complex structure of the combiner, there are sometechnical difficulties needed to be solved during the design and fabrication. Such as: theisolation between each branch is relatively poor because of multi-way, it can effectivelyenhance the isolation between each branch by setting the film resistors. Due to the smallsize of the combiner, the rather deep cavities of the waveguide, the traditional processing technology can not achieve the process of cavities, it is necessary to use wire cuttingprocessing manner.