Q3D Training.pdf

ANSOFT Q3D TRANING Introduction HFSS 3D EM Analysis S-parameter Q3D R/L/C/G Extraction Model 0 1 2 3 4 5 6 7 8 9 10 Frequency [GHz] -35 -30 -25 -20 -15 -10 -5 0 m a g n it u d e [ d B ] S11 S21 Quasi-static or full-wave techniques ? Measure the size of the interconnect in units of wavelength! ? Size λ/10, use quasi-static solvers. Output circuit model in RLGC. ? Size λ/10, and/or radiation important, use full-wave solvers. Output S, Y, and Z parameters and fields. Wavelength issues νp= λ × f ? low frequencies (lump model) : λ/10 wavelengths wire length Q3D Extractor Arbitrary 3D structure 1. 3D Fast Quasi-static EM solver 2. 2D Fast R/L/C/G EM solver Capacitance matrix ? The equation relating the total charge on a capacitor with the potential difference relative to a ground at zero volts is : Q=CV ? In a three-conductor system, matrix notation is used: 1 11 12 13 1 2 21 22 23 2 3 31 32 33 3 Q C C C V Q C C C V Q C C C V ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? The off diagonals are always negative, which accounts for the sign of the charge on each of the conductors. Q3D and circuit capacitance 11 12 21 22 1 1 2 2 s s s s C CQ V C CQ V ? ?? ? ? ? ? ? ?? ? ? ? ? ? ? ?? ? Q3D solution: circuit solution: ? ? ? ? 11 12 21 22 1 1 1 2 2 2 1 2 k k k k Q C V C V V Q C V V C V ? ? ? ? ? ? 11 11 12 12 12 s k k s k C C C C C ? ? ? ? Self-inductance Mutual-inductance ? A voltage is induced across a conductor when the number of field lines around it changes. a b s ab dI dI V L L dt dt ? ? Partial inductance ? Partial self inductance: number of field lines per amp around just the conductor segment. ? Partial mutual inductance: number of field lines per amp around both the conductor segment. Partial inductance matrix ? Defined for any collection of conductors k j jk k dI V L dt ?? 1 2 3 4 1