| With the rapid development of communication industry, various intellectual and small terminal products spring up continuously. Smart phones, tablet computers and other electronic products are improving people's life. The continuously increasing requirements of people for electronic products promote the continuous development of micro electronic industry directly and the integrated circuit package technologies have continued to be innovated as well. Among that, low temperature co-fired ceramic(LTCC) technology is widely applied in fields such as Bluetooth and WLAN for its excellent high-frequency performance, extremely high integration level and relatively low costs. In the technology, vertical via are generally applied to connect line on different dielectric substrates and since transmission characteristics of via have direct influence on transmission quality of signals, adequate research on influence factors of transmission characteristic of via must be made.In this paper, systematic research on vertical interconnection structures in LTCC is made and equivalent circuit model of vertical via is established; computational formula of parasitic parameters elicited with the application of quasi-static analysis method and Gauss theorem, etc.; input the formula elicited into MATLAB for numerical calculation and then compare it with computed results from Q3 D, which shows that the difference between computed result from formula with simulation result is smaller than 10%. And then S parameter simulation is made for equivalent circuit model in ADS and compared with HFSS simulation result of via, the result of which indicates that precision of equivalent circuit model in the paper in low frequency points and frequency pints deviating from the resonance is relatively high.Three-dimensional electromagnetic simulation model of via is established with the application of HFSS, and it has analyzed the influence of size of via(including radius of via, radius of pad, radius of anti-pad and length of via), connecting angle of transmission lines and existence of shielding via on microwave transmission characteristics of vertical interconnection structures. The simulation results show that transmission characteristics of via can be fine tuning by changing the size of via; the closer the connecting angle is to 180 degrees, the better the transmission characteristics is; the existence of shielding via can play a large role in adjustment of first resonant frequency of interconnection structures andcan make a smoother tendency of S parameter curve and increases bandwidth of interconnection structures to some extent. The special role of resonant frequency of interconnection structures playing in improvement of microwave transmission characteristics of transmission line is also studied in the thesis.Impedance matching design of vertical interconnection structures is made in ADS on the basis of impedance matching technology and the designed transmission line structure is modeled and simulated optimization in HFSS. In the paper, impedance matching of interconnection structures at 20 GHz and 50 GHz are made and the matching results show that both paralleling single branch matching and quarter-wave transformer can improve microwave transmission characteristics of via at working frequency or so and the quarter-wave transformer matches wider bandwidth with smaller area well. Besides, inspired by impedance matching design thoughts, methods of oval anti-pad and impedance control section are applied in the paper for fine adjustment of circuit impedance, which improves the microwave transmission characteristics of via to some extent. |
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