声表面波谐振式滤波器的理论分析与实验研究-梯形滤波器、梯形加纵向耦合滤波器及带阻滤波器
文献类型：学位论文
| 作者 | 刘久玲 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 中国科学院声学研究所 |
| 关键词 | 声表面波（SAW） 谐振器 梯形滤波器 纵向耦合 带阻 |
| 其他题名 | Resonator Type Surface Acoustics Wave (SAW) Filter-Ladder-Type SAW Filter, SAW Filter of Ladder-Type Coupled with Longitudinally Coupled Resonator and SAW Bandstop Filter |
| 中文摘要 | 随着移动通信的发展，低损耗、小体积SAW滤波器日益成为人们关注的焦点。而谐振式结构是设计低损耗声表面波滤波器最常采用的结构之一。本文以藕合模理论模型为理论基础，结合网络理论，分析了声表面波梯形谐振式滤波器、梯形加纵向祸合谐振式滤波器及声表面波带阻滤波器、梯形加声表面波带阻滤波器等多种声表面波谐振式滤波器。针对梯形滤波器多级级联后通带低端出现下陷的问题，本文从级联时阻抗失配的角度进行了分析，采用在级间加单端对谐振器进行阻抗补偿的措施来改善级联后的通带特性，并进行了理论模拟。为了消除纵向祸合谐振式滤波器高端带外邻近通带处的肩膀，本文将梯形结构与纵向招合相结合，用来改善纵向棍合滤波器的近阻带抑制，并从理论上进行了分析和模拟。为了解决集群移动通信系统（工作在300一400 MHz）中双工器高收发隔离度、过渡带陡、低插入损耗、小体积的要求，本文采用了声表面波带阻滤波器结构，该结构综合了SAW器件频率选择性好、LC网络插损低的特点，将之与梯形滤波器结合，实现了通带低插损，而对特定频段（如双工器的接收频段）的高抑制。论文最后在36°YX-LiTaO3压电基片和41°YX-LiNbO3压电基片上制作了相应的器件，实验结果和理论模拟基本一致：四级梯形结构加级间补偿后，通带特性得到明显改善，ldB带宽增加14％，带外抑制也提高到32dB以上，比不加补偿时增加5dB以上。纵向祸合结构加梯形滤波器后整个器件频响的矩形系数小于2，带外抑制均达到5OdB以上。梯形加带阻结构实现了通带插损2.5dB，而对特定频段的抑制达5OdB以上。 |
| 英文摘要 | As mobile telecommunication develops rapidly, the wideband, low-loss and small size SAW filter has aroused more and more attention. Resonator type SAW filter is one of the structures we often use to achieve the low-loss. Coupled-of-Modes (COM) model is used as basic theory to analyze ladder-type SAW filter, SAW filter of ladder-type coupled with longitudinally coupled resonator and SAW bandstop filter in this paper. The cascade of ladder-type SAW filter would cause the characteristic degradation in the lower side of the filter passband. By a careful impedance analysis of each stage of the filter, it is found that the above degradation is due to inter-stage impedance mismatching. Therefore, we explore the method of inter-stage compensation by adding one port SAW resonator to inter stage so as to reduce the impedance mismatching. And the theoretic simulation and the results of the experiment are given. To suppress the 'shoulder' in longitudinally coupled resonator (LCR) filter, we used SAW filter of ladder-type coupled with longitudinally coupled resonator filter. And the theoretic simulation is given. The Trunking Communication System working in 300-400 MHz requires an antenna duplexer with low insertion loss, sharp-cutoff frequency characteristics, reactive characteristic in the mutual frequency bands and small size. In order to meet all these requirements, we have proposed SAW bandstop filter, which colligate the merit of SAW filter and that of the LC circuit. By coupling it with ladder-type SAW filter we can obtain a filter with low insertion loss and high attenuation in receiving frequency band. The experimental devices are fabricated on the piezoelectric crystal 36°YX-LiTaO3 and 41°YX- LiNbO3. The experiment results are approximately coincident with the theory simulation. The characteristic of four-stage ladder-type filter with inter-stage compensation has been obviously improved in passband. The bandwidth of ldB has been increased by 14% and out-of-band rejection is more than 32dB, which increases more than 5dB compared with the filter without inter-stage compensation. The shape factor of SAW filter of ladder-type coupled with longitudinally coupled resonator filter is less than 2. And the out-of-band rejection of it is more than 50dB. Ladder-type SAW filter coupled with SAW bandstop filter achieved insertion loss less than 2.5dB and attenuation in given frequency band more than 50dB. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 75 |
| 源URL | [http://159.226.59.140/handle/311008/852]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 刘久玲. 声表面波谐振式滤波器的理论分析与实验研究-梯形滤波器、梯形加纵向耦合滤波器及带阻滤波器[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2004. |
入库方式： OAI收割
来源：声学研究所
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