Design And Optimization Of Ltcc Bandpass Filter Exploiting Tuning Space Mapping

The miniaturization of equipment pushes the modularization and miniaturization of electric components. As an indispensable component in communication system, the miniaturization of filter design has drawn significant attention. LTCC(Low Temperature Co-fired Ceramic) technology is able to miniaturize the components effectively. Currently, the components based on LTCC technology are industrialized such as intelligent antenna and balun filter. The dimension of those devices is developed to be millimeter or even sub-millimeter level. Various passive components are buried in ceramic substrate in LTCC technology. By co-firing, the planar structure turns into3D structure which leads to a smaller volume. However, the electromagnetic coupling between layers in LTCC multi-layered structure is complicated. Thus, normal optimization methods costs more time and have uncertain optimization goals. Space mapping algorithm is able to solve this problem well.In this thesis, a LTCC multi-layered filter is designed by filter lumped-circuit theory and transmission line theory. In order to solve the problem of time consuming and goal’s uncertainty in electromagnetic simulation optimization, tuning space mapping is exploited to optimize the filter structure. A LTCC multi-layered bandpass filter is designed with central frequency of2.5GHz and bandpass width of200MHz. The main work and contribution of this paper is listed below:1. According to the filter design theory, the bandpass filter is designed using frequency conversion and components conversion. Then turn the filter into the LTCC structure with J/K convertor. Finally, a four-layered bandpass filter is designed combing the design before and the transmission zero theory and the transmission line theory;2. Do research into space mapping algorithm. Choose tuning space mapping as the optimization algorithm in this paper. Exploiting tuning space mapping to design and optimize a asymmetric coupler. The simulation result verifies the effectiveness;3. Exploiting tuning space mapping in optimization of multi-layered filter. Utilizing surrogate model constructed by SNP component in ADS and the fine model constructed in HFSS. Exploiting tuning space mapping algorithm to optimize the filter iteratively. The optimized filter is obtained meeting the design specifications. The overall size is2.5mm×2.0mm×0.9mm. Its central frequency is2.5GHz, with the bandwidth of200MHz. The result verifies the feasibility and correctness of tuning space mapping. Compared with parameter sweep and implicit space mapping, tuning space mapping has a faster optimization process.