VIA COUPLING ON MULTILAYER PCB

kevinwjs

1. Introduction 13
1.1. Background 13
1.2. Purpose of the study 14
1.3.Contribution 15
1.4.Contents of the thesis 16
2. Resonant cavities and via coupling inside multilayer PCB’s 17
2.1. Introduction to the multilayer PCB’s 17
2.1.1. Description of multilayer PCB’s 17
2.1.2. Description of the via types 18
2.1.3. EMI view to the multilayer boards and vias 19
2.2. Description of the PCB cavity as a short circuited waveguide 20
2.2.1. Description of ground via configurations and related boundary conditions 20
2.2.2.Waveguide types for different boundary conditions 22
2.2.3. Simplification to the two-dimensional waveguide problem 22
3. Descriptions of the structures to be studied 23
3.1. Structures on multilayer boards 23
3.1.1. Isolated cavities 23
3.1.2. Stacked cavities 25
3.1.3.Transitions between shielded sections 25
3.1.4.Coupling between opposite open ended blind vias 27
3.2. Simplified cavities on two-layer boards 28
3.2.1. Isolated cavities 28
3.2.2. Coupled cavities 30
4.Modelling 31
4.1. Purpose of modelling in this study 31
4.2.Analytical models 31
4.2.1.Approximation of resonant frequencies and fields 31
4.2.2.Approximation of Q-values 35
4.2.3.Coupling between opposite open ended blind vias 37
4.3.Numerical models 40
4.3.1.Two-dimensional modelling of PCB cavities in the frequency domain 40
4.3.2.Approximation of unloaded Q-values 45
4.3.3.Three-dimensional modelling of PCB cavities in the time domain 46
4.3.4. Quasi static modelling of a coaxial via 48
5. Measured results 52
5.1. Description of the measurement methods 52
5.1.1.Coupling measurements 52
5.1.2. Q-value measurements 53
5.2. Measurements on multilayer boards 53
5.2.1. Isolated cavities 53
5.2.2. Stacked cavities 55
5.2.3.Transitions between shielded sections 56
5.2.4.Coupling between opposite open ended blind vias 56
5.3. Measurements on two-layer boards 59
5.3.1. Isolated cavities 59
5.3.2. Coupled cavities 73
6. Discussion 78
6.1. Measurement accuracy 78
6.2. Modelling accuracy 78
6.3.Comments on measured and modelled results 79
6.4.Improvement of isolation

cxjding

thanks

stevelu1966

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lemondavid

XIEXIE

yangbangbang

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nwu345

Good information

philipzhou

Useful books!

freezing616

恩，不错。