Analysis and Design of New Single-to-Balanced Multicoupled Line Bandpass Filters Using Low-Temperature Co-Fired Ceramic Technology
Analysis and Design of New Single-to-Balanced Multicoupled Line Bandpass Filters Using Low-Temperature Co-Fired Ceramic Technology
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DOI：
10.1109/tmtt.2008.2007186
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发表时间：
2008-11
影响因子：
4.3
通讯作者：
Chin-Lung Tsai;Yo-Shen Lin
中科院分区：
文献类型：
--
作者：
Chin-Lung Tsai;Yo-Shen Lin
本文介绍了一种新型单平衡多耦合线路带通滤波器结构的设计过程和性能。所提出的滤波器由电气长度远短于 lambda/8 的多耦合线以及加载在适当位置的并联电容器组成。通过正确设计多耦合线路的接地终端，所提出的滤波器同时配备了带通滤波器、巴伦和阻抗变压器的功能。带通特性可以轻松发展到更高阶以获得更好的选择性。采用图形变换方法进行耦合线分析，使设计过程高效、直观。为了验证所提出的移动应用滤波器的设计过程和可行性，使用低温共烧陶瓷技术在芯片类型中实现了具有不同滤波器阶数、阻抗变换比、分数带宽和中心频率的两个设计实例。二阶设计在2012的芯片尺寸中实现，三阶设计在2612的芯片尺寸中实现。此外，通过调整外部印刷电路板布局，可以在上阻带中实现和灵活控制额外的传输零，对通带性能的影响最小。这些设计的制造和测量表明，可以获得紧凑的尺寸以及测量结果和模拟结果之间的良好一致性，这证明了它们在现代移动通信应用中的适用性。
This paper presents the design procedure and performance of a new single-to-balanced multicoupled line bandpass filter structure. The proposed filter is composed of a multicoupled line of electric length much shorter than lambda/8 along with shunt capacitors loaded at suitable positions. By a proper design of ground terminations for the multicoupled line, the proposed filter is simultaneously equipped with the functionality of a bandpass filter, a balun, and an impedance transformer. The bandpass characteristic can be easily developed to higher order for better selectivity. The graph-transformation method for coupled-line analysis is adopted to make the design procedure efficient and intuitive. To validate the design procedure and feasibility of proposed filter for mobile applications, two design examples with different filter order, impedance transformation ratio, fractional bandwidth and center frequency have been implemented in chip type by using the low temperature co-fired ceramic technology. The second-order design is realized in a chip size of 2012, while the third-order one is realized in a chip size of 2612. Moreover, an additional transmission zero in the upper stopband can be achieved and controlled flexibly by adjusting the outer printed circuit board layout with minimum effect on passband performance. Fabrication and measurement of these designs show that compact sizes and good agreements between measured and simulated results can be obtained, which demonstrate their suitability in modern mobile communication applications.