毫米波固态功率合成技术研究

【作者】 陈昌明；

【导师】 徐军；

【作者基本信息】 电子科技大学 ， 无线电物理， 2006， 硕士

【摘要】 高功率放大器是微波和毫米波频段发射机必不可少的关键部件。特别是在毫米波频段,鉴于单个单片集成电路可能提供的功率有限,要提高系统的输出功率就需要采用功率合成技术。为此,宽带并具有良好散热特性的高功率合成器的研制就成为毫米波发射系统的基本问题。本文在分析和研究各种固态功率合成技术的基础上,采用波导基的空间功率合成器结构方案,立足于国内的装配工艺,对毫米波功率合成电路作了探索性研究。主要内容为:1.研究和对比了各种固态功率合成技术的特点,详细地分析了波导基空间功率合成器的工作原理,提出了一种基于双对极鳍线-微带过渡的2×2路毫米波功率合成器结构,借助三维场仿真软件CST对该无源网络进行了优化设计。在整个Ka频段内实测的背对背插损均小于1.0dB,回波损耗优于10.0dB。2.设计了Ka频段鳍线-微带的过渡,并将其运用于功率驱动级放大器之中。在驱动级放大器的工作频率范围内实测的功率增益不平坦度小于1.18dB,获得的最大输出功率(1.37W)带宽优于1.5GHz。3.研制了Ka频段5W功率合成放大器,设计了紧凑的偏置电路和MMICs功率单片的电源保护电路。该功率合成放大器在低于MMICs功率单片额定工作值的情况下获得了1.7 GHz带宽的最大饱和输出功率5.94W(连续波);整个带内合成效率估计平均为82%,最大合成效率达87%,功率相加效率(PAE)约为13.6%;若电源达到MMICs单片的额定值,估计最大输出射频功率将会达到7W。4.通过采用特殊的高导热材料,利用ANSYS软件构建了功放的热模型,进行了热仿真和优化设计。在放大器自然散热的情况下,最终达到热平衡状态的腔体外壳温度为55℃,此时测试的最大输出功率几近维持在5.7W,显示出了该放大器良好的散热特性。5.展望了该功率合成器在毫米波系统中的良好应用前景以及这些技术将有可能在未来的毫米波领域起到极为关键的作用。更多还原

【Abstract】 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更多还原