Design Of Passive Filter Based On LTCC Technology

In recent years, filter has attracted much attention as it plays a very important role both in the communication system and EMI field. With the development of communication technology, the small-size, integrated, high performance and low-cost RF and microwave devices are the current trend. LTCC (Low Temperature Co-fired Ceramic) has achieved more and more application. This paper will present the design method of filters based on LTCC technology for two different applications.In the three major elements of LTCC technology---- material, process and design, this paper focuses on the design and researches of the LTCC devices based on the current processing qualification. It introduces the general method and flow of the design of LTCC devices. Meanwhile,it has a detailed introduction with the elementary component used in LTCC.Filter is the most commonly used device in the communication system. The LTCC bandpass filters achieved in this paper are based on the theory of lumped element circuit, and discussed focus on the coupled characteristic between resonators, and achieved good performance by electric coupling. Then it introduce two transmission zeros by making use of the parasitical effects.Common mode filter is widely used in the EMI fields. This paper presents the normal knowledge of the common-mode devices, and analyses the advantages and disadvantages of different kinds. Then it introduced LTCC common mode filter structures and design methods. And it introduces the advanced testing methods -- mixed mode S-parameter test. Then it presents the normal design method of LTCC common mode filter. Finally, it introduces my innovative design structure, and the predictions of its future.