Coaxial Waveguide-based Millimeter-wave Spatial Power Combining Technology

High power Millimeter wave source is the Key component of the Millimeter wave radar, Communication, Disturb machine, accurate missile guided system's transmitter front-end. Solid - state device are taken much count of its low Direct Current Voltage, high Reliability, well Shock resistance, compact circuit Structure, small Dimension, Light Weight. However,as the increase of frequency, the output power from an individual solid-state device rapidly decreased, which can not meet the requirements of application. The power combine technique which combining the output power of much number of correlation solid-state device or separate device are the efficiency method to enhance the output power of the millimeter wave system, is wildly used.Conventional hybrid-type power-combining circuits, such as the Wilkson power divider, Lange coupler, and branch-line coupler, suffer from low power-combining efficiency and narrow bandwidth at microwave and millimeter frequencies. To meet these requirements, various techniques, such as quasi-optical and waveguide-based spatial power-combining approaches, have been proposed at these frequencies. These techniques are preferred over traditional corporate combiners because of their low insertion loss, and their high power-combining efficiency. The rectangle waveguide-based, coaxial waveguide-based, substrate integrated waveguide-based millimeter wave spatial power combining techniques and solid-state power amplifier technology are deeply investigated in this project by theory analysis, design and simulation and experimental study. The gained research achievements in this project are as the following.1. A novel four way power divider/combiner based on rectangle waveguide is presented, a four way power combining amplifier is designed by the one to four power divider/combiner. The combiner sums the power of the four devices directly in one step without having to proceed through several combining stages. So this power combiner has low insertion loss and high power-combining efficiency which is a wideband, high efficiency power combiner. 2. By research of the waveguide–antipodal fin line - micro strip transitions, a novel wideband, fabricated easily, wideband transitions is presented。A 16-way coaxial waveguide-based Ka-band millimeter wave spatial power combiner with pile structure has been designed. The optimal results shown that the insert loss is less than 0.3dB and return loss less than -15dB in the frequency range from 25GHz to 42GHz based on back to back structure.3. A novel wideband transition between rectangle waveguide and substrate integrated waveguide is presented. Measured results show that a good agreement with simulation and an insertion loss less than 1.5 dB at 26.5–40 GHz are obtained for a back-to-back structure.A high efficiency 16-way coaxial waveguide-based Ka-band millimeter wave spatial power combiner with pile structure has been designed and deeply investigated by performance simulation secondly. The optimal results of 16 - way coaxial waveguide– based Ka-band back to back power combiner performance shown that the insertion loss less than 0.6dB in the frequency range from 26.5GHz to 40GHz.