【作者】 熊莹霞；

【导师】 尹秋艳；

【作者基本信息】 华东师范大学 ， 无线电物理， 2005， 硕士

【摘要】 本文所研究的可调谐振腔带通滤波器是光频率梳系统中一个重要部件,它具有带宽小、通带插损小,阻带抑制度高、频率调谐范围内带宽和滤波曲线保持不变、结构小型化、制作重复性高等特点。其在系统中的作用是将频率非常高的光学振动频率调制到较低的微波频率上,使该频率能够被电子系统记录,达到和已有的原子钟微波频率标准相连接,研制出比目前最好的原子喷泉钟精度更高的光钟系统的目的。在整个研究的过程中,概括起来主要做了以下几个方面的工作:从滤波器的网络设计理论入手,在耦合谐振腔带通滤波器的理论基础上,研究了从低通原型滤波器到耦合谐振腔可调带通滤波器的设计过程,包括电路变换采用的K、J变换器的实现方法、耦合谐振腔滤波器的网络电路实现方法、物理结构上滤波器输入、输出矩形耦合环的设计方法、腔间耦合圆孔的设计方法。针对可调滤波器的设计,研究分析了可调滤波器频率变化和滤波器性能参数之间的关系,得出实际设计时这些参数和滤波器结构的设计公式。滤波器的设计是工作的重点,包括基本结构的计算设计、利用HFSS仿真软件进行的优化设计和滤波器的调试工作三部分。前两部分工作主要是在理论设计的基础上,实际计算并利用软件得出实际加工滤波器的各个部件更精确的尺寸大小。针对所设计可调谐振腔带通滤波器的特点,在仿真过程中采用了一些特殊的处理方法,例如可调电容片的设计。第三部分的工作主要是对加工好的滤波器进行调试,包括输入、输出耦合环结构的调整,以及对补偿电容片的调整,使滤波器的各个谐振腔能够谐振在相同的频率上,且保证在不同的中心频率上滤波器的特性曲线和绝对带宽不变。测量制成的成品滤波器的性能,并分析了滤波器某些性能不能完全满足要求存在的原因,为进一步的改进提供了指导的方向。更多还原

【Abstract】 The tunable bandpass cavity filter presented here is an essential part of the optical-frequency-comb system. The filter enjoys such merits: narrow bandwidth, low insert-loss in the passband, and high attenuation in the stopband, wide stopband and changeless bandwidth and filter characteristics. And besides, its structure is compact and easily to be manufactured. The introduced filter is used to modulate the optical vibration-frequency to microwave-frequency. To do so is because the value of the former is much higher than that of the later. Then the electrical devices can record the modulated frequency. Equipped with this tunable bandpass cavity filter, the optical-frequency-comb system, which has the optical-frequency standard, is offered a way to connect with the atom-clock microwave-frequency one. So it will contribute to design an optical-clock with higher precision than the atom-clock. During the course of the research, the focuses are put on the followings: On the base of the theories of the network design and coupling-cavity filters design, we study the processes from the lowpass filter prototypes to the tunable bandpass coupling-cavity filters, including the design method of the K/J inventor, network prototype circuits of the coupling-cavity bandpass filters, design formulas of the input/output rectangular coupling loop and the coupling hole between the cavities. About the tunable filters, we analyze the relation between the variable center frequency and the filter’s parameters, and design formulas are presented. The emphases of the work are to design the filter, including simulation process with the help of the HFSS software, and the adjustment process. The first part is to obtain the exacter dimensions of the filter on the base of the former analysis. For unique characters of our filter, we adapt some special methods to simulate, such as the way to design the tunable capacitance patch. The second part is to adjust the filter. That means to adjust the position and area of the input/output coupling loop, as well as the compensation capacitance patch, in order to make the five cavities resonate on the same frequency, and remain the constant absolute bandwidth and filter characteristics. To measure the performances of the finished filter, and to analyze the reasons of dissatisfactory indexes.更多还原