摘要：采用0.18μm工艺设计1个用于UWB接收端的4阶切比雪夫有源RC带通滤波器。给出1种有损积分器直流增益补偿策略,从而减小滤波器对运算放大器直流增益的要求。同时,采用1种数控电阻的方式实现通带增益的调节。仿真结果表明:所设计的滤波器在通带增益为0 dB时,通带纹波增益为0.112 dB,下3 dB频率为156 kHz,上3 dB频率为259 MHz,带宽为258.844 MHz;频率为500 MHz处的信号衰减为28.25 dB,频率为792 MHz处的信号衰减为45.16 dB,完全符合UWB接收端对带通滤波器的性能指标要求。

摘要：Metal organic chemical vapor deposition(MOCVD) is a key equipment in the manufacturing of semiconductor optoelectronic devices and microwave devices in industry. Heating system is a vital part of MOCVD. Specific heating device and thermal control technology are needed for each new reactor design. By using resistance-wire heating MOCVD reaction chamber model, thermal analysis and structure optimization of the reactor were developed from the vertical position and the distance between coils of the resistance-wire heater. It is indicated that, within a certain range, the average temperature of the graphite susceptor varies linearly with the vertical distance of heater to susceptor, and with the changed distances between the coils; furthermore, single resistance-wire heater should be placed loosely in the internal and tightly in the external. The modulate accuracy of the temperature field approximately equals the change of the average temperature corresponding to the change of the coil position.