| As a vertical interconnect channel, through-hole plays an important role in multi-layer PCBs and IC packages. With scale miniaturization and function highly integrated, the total layers of microwave/RF circuits are increasing dramatically, through-hole via is one of the most important and indispensable components; and with the increase of device operating frequency, the performance of via to the impact of the circuit can no longer be ignored.Based on theoritical analysis, experimental verification and software simulation, this thesis studies the effects of board boundary conditions, physical parameters and structural variation on EM characterization and signal transmission performance.Through hole is modeled mathmatically and solved by Piecewise Sinusoidal (PWS) basis function based matrix-penciled Moment Method. Network theory is used to splite the multilayer via structure into exterior problem and interior problem, and matrix-penciled Moment Method is deployed to solve the exterior problem theoretically, and the effect of via radius, height and effictive dielectric constant of substrate material on via performance can be calculated, the mode conversion caused by via discontinuities is analyzed. Mixed programming between MATLAB source code and VC user interface control by Component Object Modal (COM) technology, is used to compose computational software with GUI which provides convenience for professional staffs.And then, based on experiments and combined with three-dimensional full-wave electromagnetic simulation software, the frequency domain and time domain performance of the through-hole via is analyzed. A series of test boards are designed and measured, the actual measurement frequency bands ranges from the baseband to 20GHz, and the frequency characteristics is obtained. The variable physical parameters of test board include through-hole radius, pad radius and thickness of the outer substrate. And also the effects of combonation of the connector and the fixture on the measurement results are analyzed.Finally, researches on performance optimization of through hole are conducted. The improving method of through hole performance by increasing return path, impedance controlled, and eliminating stub is discussed, the capacitive and inductive discontinuity of through hole is analyzed, and verified by eye diagram. |
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