tailieunhanh - Three-Dimensional Integration and Modeling Part 7

Tham khảo tài liệu 'three-dimensional integration and modeling part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CAVITY-TYPE INTEGRATED PASSIVES 51 External Slot Length SL ụm FIGURE External quality factor Qext evaluated as a function of external slot length SL . at port 2. The vertical transition consists of five stacked signal vias penetrating through circular apertures see Fig. a on the ground planes metals 2 3 4 and 5 and connecting an embedded microstrip line on metal 6 to a CPW measurement pads on metal 1. In order to match to the 50 Í2 feedlines the diameter of the circular apertures is optimized to be mm for a signal via diameter of 130 m while the width of the microstrip line tapers out as it approaches the overlying CPW. Also eight shielding vias two connecting metals 1 CPW ground planes to 5 six connecting metals 2 to 5 are positioned around the apertures to achieve an optimum coaxial effect 69 . The number of shielding vias is determined with regard to the LTCC design rules. The filters including CPW pads and a vertical transition were fabricated in LTCC. And measured on a HP8510C Vector Network Analyzer using SOLT calibration. Figure a depicts the 3D overview of the complete structure that was simulated. The Wincal software gives us the ability to de-embed capacitance effects of CPW open pads and inductive effects of short pads from the measured S-parameters so that the loading shift effect could be negligible. Figure b shows the photograph of the fabricated filter with CPW pads and a transition whose size is X X 1 mm3. The cavity size is determined to be X X mm3 L X WX Hin Fig. . Figure a shows a comparison between the simulated and the measured S-parameters of the three-pole vertically stacked bandpass filter. The filter exhibits an insertion loss dB which is higher than the simulated value of dB. The main source of this discrepancy might be caused by the radiation loss from the thru line that could not be de-embedded because of the 52 THREE-DIMENSIONAL INTEGRATION a Frequency GHz b Intenal .