Millimeter-wave Solid-state Power Combining Technology Research

High-power amplifiers are a necessary component of wireless transmitters at microwave and millimeter-wave frequencies. Especially at millimeter-wave frequencies, power available from each monolithic microwave integrated circuit (MMIC) is limited, and subsequent power combining is required to achieve the desired output power. High-efficiency power combiners with broad bandwidth and good thermal property are essential for this purpose.In this thesis, various solid-state power-combining techniques have been studied and analyzed. Then waveguide-based millimeter-wave power combining structures are explored and implemented according to domestic assembly techniques. The main results are as follows:1. The characteristics of various solid-state power-combining techniques and the principles of the waveguide-based power combining structure are compared and analyzed in detail. The power combiner is based on a double antipodal finline-to-microstrip transition structure. The proposed 2×2 combining structure is optimized by using 3-D fields simulation tools CST. The measured back-to-back insertion loss is less than 1.0dB and return loss is better than 10.0dB within the entire Ka-band.2. Finline-to-microstrip transitions are designed and used in the power-driver at Ka-band. The power driver yields output power with a gain variation less than±1.18dB and a maximum of 1.37-W output power within the entire band of interest. The large-signal bandwidth of this power-driver is 1.5GHz.3. A 5-W millimeter-wave power-combining amplifier is implemented and fabricated. The compact bias circuits and power-protection circuits for MMICs is designed. At the operating voltage and current less than rated values, the amplifier provides a maximum of 5.94-W(continuous wave)output power when driven into saturation. The average combining efficiency over the operating band was estimated at 82%. The maximum combining-efficiency and the overall power-added efficiency (PAE) is 87% and 13.6%, respectively. It maybe provides output RF power of 7.0W by...