Research On Spatial Power Combining Network Based On Waveguide

With the rapid development of modern electronic technologies, there are increasing demands forsystems of miniaturized and high-power communication, electronic counter measures (ECM) andradar due to the fact that high output power means better communication quality, stronger interferenceand anti interference capacity, further radar range. The output power of an individual solid-statedevice is rather limited in Ka and higher band which can not satisfy the demands of high frequencyand high power system. So, power combination techniques are usually used to obtain higher outputpower in engineering. And for miniaturization purposes, it is necessary to design a kind of powercombining network, applying for monolithic microwave integrated circuit (MMIC) powercombination.This paper has discussed the power combination theory and the main influence factors on outputpower and combining efficiency. A Ka-band power dividing/combining network based on waveguideto microstrip dual-probe structure has been discussed and analyzed which can be used in MMICpower combination. And the network has been improved to get better output power and combiningefficiency using odd-even mode theory. The main work in this thesis can be summarized as follows:A Ka-band four-way spatial power dividing/combining network based on waveguide is proposed torealize equal power division between the four microstrip lines and a rectangular waveguide. The lossof the combining network is0.4dB-0.8dB while the combining efficiency of the network is83.18%.An improved four-way spatial power dividing/combining network is proposed and analyzed. Theisolation resistance has been introduced between the microstrip lines. And the equivalent circuit of theimproved network is analyzed in details using the odd-even mode theory. The improved network hashigher isolation and smaller reflection which results in reduced insertion loss of the combiningnetwork and improved output power of the combining network. The loss of the spatial powercombining network is0.3dB-0.5dB and the combining efficiency of the network is89.13%.A Ka-band four-way spatial power combining amplifier is proposed and analyzed. Based on theresearch and experiments, the four-way power combining amplifier which is consisted of two spatialpower combining network connected with4TGA4505MMIC power amplifiers (PAs), can provideoutput power more than39.01dBm(7.96W) from28GHz to31GHz, and the highest power with40.22dBm(10.52W) at28GHz. The combining efficiency from28GHz to32GHz is better than74.8%.