Could some electronics suru here clarify this a bit ? A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S parameter estimation.

# SPICE S parameter for frequency dependent circuit components question

Started by ●November 19, 2021

Reply by ●November 19, 20212021-11-19

On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee <dakupoto@gmail.com> wrote:>Could some electronics suru here clarify this a bit ? >A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? >At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S >parameter estimation.Like these? https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 I've smoked these in a pulse application, at way below rated RMS current. Skin loss! I had to wind my own, which I hate to do. https://www.dropbox.com/s/o2hz6oi08agzdy8/T850_Inductor.JPG?raw=1 Certainly an s-param table should account for changes in losses vs frequency. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.

Reply by ●November 19, 20212021-11-19

jlarkin@highlandsniptechnology.com wrote:> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee > <dakupoto@gmail.com> wrote: > >> Could some electronics suru here clarify this a bit ? >> A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? >> At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S >> parameter estimation. > > Like these? > > https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 > > I've smoked these in a pulse application, at way below rated RMS > current. Skin loss! I had to wind my own, which I hate to do. > > https://www.dropbox.com/s/o2hz6oi08agzdy8/T850_Inductor.JPG?raw=1 > > Certainly an s-param table should account for changes in losses vs > frequency.Calculating the skin effect losses to put _into_ the S parameters needs an EM solver, though, assuming that is what the OP needs. Spice doesn't do that. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com

Reply by ●November 19, 20212021-11-19

Am 19.11.21 um 19:08 schrieb Phil Hobbs:> jlarkin@highlandsniptechnology.com wrote: >> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee >> <dakupoto@gmail.com> wrote: >> >>> Could some electronics suru here clarify this a bit ? >>> A planar inductor has a frequency dependent resistance(skin, >>> proximity effecrs). Can the small signal S parameters for such an >>> inductor be measured using stabdard SPICE small signal(.AC) analysis ? >>> At each frequency in a specified frequency range, the series >>> resistance is different. Does this new resistance at each frequency >>> have effect on the S >>> parameter estimation. >> >> Like these?Probably really flat, like etched on a PCB or on SiO2 etc.>> https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 >> >> I've smoked these in a pulse application, at way below rated RMS >> current. Skin loss! I had to wind my own, which I hate to do. >> >> https://www.dropbox.com/s/o2hz6oi08agzdy8/T850_Inductor.JPG?raw=1 >> >> Certainly an s-param table should account for changes in losses vs >> frequency. > > Calculating the skin effect losses to put _into_ the S parameters needs > an EM solver, though, assuming that is what the OP needs. Spice > doesn't do that.< https://en.wikipedia.org/wiki/Comparison_of_EM_simulation_software > A few are missing, like Keysight EMPRO or https://www.sonnetsoftware.com/ Spice is also not the first choice for S-parameter handling. --------- Now that I'm at it, I have made a test board on JLCPCB's 7628 4 layer process. < https://www.flickr.com/photos/137684711@N07/51691780129/in/dateposted-public/ > Somewhere I've written down that 50 Ohm on the top level should be 11.55 mil. My test line is 12 mil wide as drawn in Altium. I don't have any idea how much they correct for underetching etc. < https://www.flickr.com/photos/137684711@N07/51691101706/in/dateposted-public/ > It hits quite closely, somewhat more closer to 11 mil would probably be exact. My SMA-decals are much too fat for the 4 layer process. From x=0.5 to 3.5 divisions is the internal 50 Ohm line in the 54754A TDR plug in. Around division 4 is the SMA of the test board. It is a capacitive load. Divisions 4.5 to 7.5 is the 12 mil line on the multilayer. There is no real difference to the plug-in-internal 50 Ohm line. Then follows the smaller dip of the unpopulated SMA-connector and then the full reflection at the open end. The LMX2594 10 MHz-15 GHz synthesizer worked immediately :-) The USB-to-SPI dongle board cannot tell the difference between the eval board and the test board. I have not yet written a single line of software. Cheers, Gerhard

Reply by ●November 19, 20212021-11-19

On Friday, November 19, 2021 at 3:59:43 AM UTC-8, daku...@gmail.com wrote:> Could some electronics suru here clarify this a bit ? > A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ?Yes. You'll need to use LAPLACE = {something}. LAPLACE does not have the troubles in .AC that it does for transient simulation. I have to say that I don't bother messing with this for the non-ferrous core coils anymore. I mean the "chip surface mount RF coils." About 15 years ago I was playing with it, and had a test file for a CCI 1008HQ_R10_ coil testing different LAPLACE usage, because I was not sure I understood it. As follows: ============================================= *1008HQ_R10_multi.mod *Used to test various models of the 100nH 1008HQ inductor *ABS(s) 1008HQ_R10_abss Upper * R1 R2 Limit * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 .SUBCKT 1008HQ_R10_abss 1 4 R1 3 4 14.00 R2 1 2 0.1600 C1 2 3 0.210E-12 L1 5 4 100.00E-9 GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( abs(s)/(2*pi) ) ) ) R99 2 5 1G .ENDS *--------------------- * Upper * R1 R2 Limit * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 .SUBCKT 1008HQ_R10 1 4 R1 3 4 14.00 R2 1 2 0.1600 C1 2 3 0.210E-12 L1 5 4 100.00E-9 GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) R99 2 5 1G .ENDS *--------------------- * -j 1008HQ_R10_negj Upper * R1 R2 Limit * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 .SUBCKT 1008HQ_R10_negj 1 4 R1 3 4 14.00 R2 1 2 0.1600 C1 2 3 0.210E-12 L1 5 4 100.00E-9 GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) R99 2 5 1G .ENDS *--------------------- *skinEff 1008HQ_R10_skinEff Upper * R1 R2 Limit * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 .SUBCKT 1008HQ_R10_skinEff 1 4 R1 3 4 14.00 R2 1 2 0.1600 C1 2 3 0.210E-12 L1 5 4 100.00E-9 GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( s/(2*pi) ) ) ) R99 2 5 1G .ENDS *--------------------- *skinEffSqrt2 1008HQ_R10_skinEffSqrt2 Upper * R1 R2 Limit * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 .SUBCKT 1008HQ_R10_skinEffSqrt2 1 4 R1 3 4 14.00 R2 1 2 0.1600 C1 2 3 0.210E-12 L1 5 4 100.00E-9 GLAP 2 5 2 5 LAPLACE = ( 1/( sqrt(2)*1.31E-004*sqrt( s/(2*pi) ) ) ) R99 2 5 1G .ENDS *--------------------- I think I ended up using GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) The quantity 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) looks strange, but I think it makes it real in the end, which we want for a resistor. In the end I had generated a bunch of entire CCI chip inductor family libraries. I haven't used them for many years because I just use AWR and Modelithics, and I didn't end up thinking it bought me much.> At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S > parameter estimation.Yes, strictly and in principle. But the weight of importance may or may not matter depending on what you're doing. An example library is the following available from CCI: * SPICE MODEL SUBCIRCUIT DATA SOURCE: 026011F-spice0.txt * AUTO-GENERATED DATE: 29-Mar-2020 11:59:00 * Coilcraft Inductor (CCI) Family: 026011 * Dummy header part .SUBCKT 026011F-___ 1 4 R1 1 4 1E-12 .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-270 1 1000 1440 0.11 0.3 7.8e-005 0.05 0.018 0.0017 5e-010 .SUBCKT 026011F_270 1 4 .param R1 1440 .param R2 0.11 .param C1 3e-013 .param k1 7.8e-005 .param k2 0.05 .param k3 0.018 .param k4 0.0017 .param k5 5e-010 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-720 1 1000 1080 0.4 0.22 0.000152 0.078 0.077 0.0035 5e-007 .SUBCKT 026011F_720 1 4 .param R1 1080 .param R2 0.4 .param C1 2.2e-013 .param k1 0.000152 .param k2 0.078 .param k3 0.077 .param k4 0.0035 .param k5 5e-007 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-151 1 1000 1480 0.6 0.088 0.000106 0.11 0.163 0.0067 5e-007 .SUBCKT 026011F_151 1 4 .param R1 1480 .param R2 0.6 .param C1 8.8e-014 .param k1 0.000106 .param k2 0.11 .param k3 0.163 .param k4 0.0067 .param k5 5e-007 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-271 1 1000 2200 1.15 0.027 7.6e-005 0.158 0.282 0.0106 5e-007 .SUBCKT 026011F_271 1 4 .param R1 2200 .param R2 1.15 .param C1 2.7e-014 .param k1 7.6e-005 .param k2 0.158 .param k3 0.282 .param k4 0.0106 .param k5 5e-007 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-431 1 1000 1380 1.85 0.028 0.00015 0.254 0.437 0.014 5e-007 .SUBCKT 026011F_431 1 4 .param R1 1380 .param R2 1.85 .param C1 2.8e-014 .param k1 0.00015 .param k2 0.254 .param k3 0.437 .param k4 0.014 .param k5 5e-007 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS * Lower Upper * Limit Limit *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 * 026011F-561 1 1000 690 2.8 0.022 0.0001 0.239 0.584 0.0172 5e-007 .SUBCKT 026011F_561 1 4 .param R1 690 .param R2 2.8 .param C1 2.2e-014 .param k1 0.0001 .param k2 0.239 .param k3 0.584 .param k4 0.0172 .param k5 5e-007 R2 1 2 {R2} R1 3 4 {R1} C1 2 3 {C1} Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } R98 2 5 1G GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } R99 5 4 1G Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } .ENDS

Reply by ●November 19, 20212021-11-19

Jan Panteltje wrote:> On a sunny day (Fri, 19 Nov 2021 13:08:52 -0500) it happened Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote in > <ab395e8b-34ff-5f54-6c4d-fb3e9842b1d2@electrooptical.net>: > >> jlarkin@highlandsniptechnology.com wrote: >>> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee >>> <dakupoto@gmail.com> wrote: >>> >>>> Could some electronics suru here clarify this a bit ? >>>> A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such >>>> an inductor be measured using stabdard SPICE small signal(.AC) analysis ? >>>> At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each >>>> frequency have effect on the S >>>> parameter estimation. >>> >>> Like these? >>> >>> https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 >>> >>> I've smoked these in a pulse application, at way below rated RMS >>> current. Skin loss! I had to wind my own, which I hate to do. > > I am sure you know ohmic losses are i^2 * R. > So if you have a 1 Ohm resistor, and have 1A during 1 second you dissipate 1 Watt during that second. > 1^2 * 1 * 1 = 1 > > But if you have, in same resistor, 2A during half a second and zero A during the other half, > then you have dissipated 2 Watt during that second, while the average current is still 1 A. > 2^2 * 1 * .5 = 2 > > If you have in same resistor, 4A during 1/4 second and zero A during the rest of that second, > then you have, in same resistor, dissipated 4W during that second while the average current is still 1A. > 4^2 * 1 * .25 = 4W > > etc. > Pulses, beware! > > > >> >>> https://www.dropbox.com/s/o2hz6oi08agzdy8/T850_Inductor.JPG?raw=1 >>> >>> Certainly an s-param table should account for changes in losses vs >>> frequency. > > > pfffff >As some random Dutchman noted in another thread, you should get your quoting right--I didn't write that. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com

Reply by ●November 20, 20212021-11-20

On Fri, 19 Nov 2021 18:36:50 GMT, Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> wrote:>On a sunny day (Fri, 19 Nov 2021 13:08:52 -0500) it happened Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote in ><ab395e8b-34ff-5f54-6c4d-fb3e9842b1d2@electrooptical.net>: > >>jlarkin@highlandsniptechnology.com wrote: >>> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee >>> <dakupoto@gmail.com> wrote: >>> >>>> Could some electronics suru here clarify this a bit ? >>>> A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such >>>> an inductor be measured using stabdard SPICE small signal(.AC) analysis ? >>>> At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each >>>> frequency have effect on the S >>>> parameter estimation. >>> >>> Like these? >>> >>> https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 >>> >>> I've smoked these in a pulse application, at way below rated RMS >>> current. Skin loss! I had to wind my own, which I hate to do. > >I am sure you know ohmic losses are i^2 * R. >So if you have a 1 Ohm resistor, and have 1A during 1 second you dissipate 1 Watt during that second. >1^2 * 1 * 1 = 1 > >But if you have, in same resistor, 2A during half a second and zero A during the other half, >then you have dissipated 2 Watt during that second, while the average current is still 1 A. >2^2 * 1 * .5 = 2 > >If you have in same resistor, 4A during 1/4 second and zero A during the rest of that second, >then you have, in same resistor, dissipated 4W during that second while the average current is still 1A. >4^2 * 1 * .25 = 4W > >etc. >Pulses, beware! > >That inductor fried at an RMS current way below specified max. It was skin loss. My home-made inductor was OK: less proximity effect, more air cooling, and the gap-pad. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.

Reply by ●November 20, 20212021-11-20

On Friday, November 19, 2021 at 7:16:58 AM UTC-8, jla...@highlandsniptechnology.com wrote:> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee > <daku...@gmail.com> wrote: > > >Could some electronics suru here clarify this a bit ? > >A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? > >At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S > >parameter estimation.> Like these? > > https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 > > I've smoked these in a pulse application, at way below rated RMS > current. Skin loss! I had to wind my own, which I hate to do.Oh, that's just the tip of the iceberg. In pulse applications, there's mechanical stress to consider. as well. This little item, for instance, had a mechanical stress event <http://www.capturedlightning.com/frames/gallery/coins6.jpg> and no amount of SPICE expertise can model that issue.

Reply by ●November 20, 20212021-11-20

On Saturday, November 20, 2021 at 3:35:48 AM UTC+5:30, Simon S Aysdie wrote:> On Friday, November 19, 2021 at 3:59:43 AM UTC-8, daku...@gmail.com wrote: > > Could some electronics suru here clarify this a bit ? > > A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? > Yes. You'll need to use LAPLACE = {something}. LAPLACE does not have the troubles in .AC that it does for transient simulation. I have to say that I don't bother messing with this for the non-ferrous core coils anymore. I mean the "chip surface mount RF coils." > > About 15 years ago I was playing with it, and had a test file for a CCI 1008HQ_R10_ coil testing different LAPLACE usage, because I was not sure I understood it. As follows: > ============================================= > *1008HQ_R10_multi.mod > *Used to test various models of the 100nH 1008HQ inductor > > *ABS(s) 1008HQ_R10_abss Upper > * R1 R2 Limit > * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) > * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 > .SUBCKT 1008HQ_R10_abss 1 4 > R1 3 4 14.00 > R2 1 2 0.1600 > C1 2 3 0.210E-12 > L1 5 4 100.00E-9 > GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( abs(s)/(2*pi) ) ) ) > R99 2 5 1G > .ENDS > *--------------------- > * Upper > * R1 R2 Limit > * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) > * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 > .SUBCKT 1008HQ_R10 1 4 > R1 3 4 14.00 > R2 1 2 0.1600 > C1 2 3 0.210E-12 > L1 5 4 100.00E-9 > GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) > R99 2 5 1G > .ENDS > *--------------------- > * -j 1008HQ_R10_negj Upper > * R1 R2 Limit > * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) > * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 > .SUBCKT 1008HQ_R10_negj 1 4 > R1 3 4 14.00 > R2 1 2 0.1600 > C1 2 3 0.210E-12 > L1 5 4 100.00E-9 > GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) > R99 2 5 1G > .ENDS > *--------------------- > *skinEff 1008HQ_R10_skinEff Upper > * R1 R2 Limit > * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) > * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 > .SUBCKT 1008HQ_R10_skinEff 1 4 > R1 3 4 14.00 > R2 1 2 0.1600 > C1 2 3 0.210E-12 > L1 5 4 100.00E-9 > GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( s/(2*pi) ) ) ) > R99 2 5 1G > .ENDS > *--------------------- > *skinEffSqrt2 1008HQ_R10_skinEffSqrt2 Upper > * R1 R2 Limit > * PartNumber (OHM) (OHM) C(pF) L(_H) k (MHz) > * 1008HQ-R10 14.0 0.160 0.210 100.00 1.31E-004 1400 > .SUBCKT 1008HQ_R10_skinEffSqrt2 1 4 > R1 3 4 14.00 > R2 1 2 0.1600 > C1 2 3 0.210E-12 > L1 5 4 100.00E-9 > GLAP 2 5 2 5 LAPLACE = ( 1/( sqrt(2)*1.31E-004*sqrt( s/(2*pi) ) ) ) > R99 2 5 1G > .ENDS > *--------------------- > I think I ended up using > > GLAP 2 5 2 5 LAPLACE = ( 1/( 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) ) ) > > The quantity 1.31E-004*sqrt( -1*sqrt(-1)*s/(2*pi) ) looks strange, but I think it makes it real in the end, which we want for a resistor. > > In the end I had generated a bunch of entire CCI chip inductor family libraries. I haven't used them for many years because I just use AWR and Modelithics, and I didn't end up thinking it bought me much. > > At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S > > parameter estimation. > Yes, strictly and in principle. But the weight of importance may or may not matter depending on what you're doing. > > > An example library is the following available from CCI: > > * SPICE MODEL SUBCIRCUIT DATA SOURCE: 026011F-spice0.txt > * AUTO-GENERATED DATE: 29-Mar-2020 11:59:00 > * Coilcraft Inductor (CCI) Family: 026011 > > * Dummy header part > .SUBCKT 026011F-___ 1 4 > R1 1 4 1E-12 > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-270 1 1000 1440 0.11 0.3 7.8e-005 0.05 0.018 0.0017 5e-010 > .SUBCKT 026011F_270 1 4 > .param R1 1440 > .param R2 0.11 > .param C1 3e-013 > .param k1 7.8e-005 > .param k2 0.05 > .param k3 0.018 > .param k4 0.0017 > .param k5 5e-010 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-720 1 1000 1080 0.4 0.22 0.000152 0.078 0.077 0.0035 5e-007 > .SUBCKT 026011F_720 1 4 > .param R1 1080 > .param R2 0.4 > .param C1 2.2e-013 > .param k1 0.000152 > .param k2 0.078 > .param k3 0.077 > .param k4 0.0035 > .param k5 5e-007 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-151 1 1000 1480 0.6 0.088 0.000106 0.11 0.163 0.0067 5e-007 > .SUBCKT 026011F_151 1 4 > .param R1 1480 > .param R2 0.6 > .param C1 8.8e-014 > .param k1 0.000106 > .param k2 0.11 > .param k3 0.163 > .param k4 0.0067 > .param k5 5e-007 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-271 1 1000 2200 1.15 0.027 7.6e-005 0.158 0.282 0.0106 5e-007 > .SUBCKT 026011F_271 1 4 > .param R1 2200 > .param R2 1.15 > .param C1 2.7e-014 > .param k1 7.6e-005 > .param k2 0.158 > .param k3 0.282 > .param k4 0.0106 > .param k5 5e-007 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-431 1 1000 1380 1.85 0.028 0.00015 0.254 0.437 0.014 5e-007 > .SUBCKT 026011F_431 1 4 > .param R1 1380 > .param R2 1.85 > .param C1 2.8e-014 > .param k1 0.00015 > .param k2 0.254 > .param k3 0.437 > .param k4 0.014 > .param k5 5e-007 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDS > > * Lower Upper > * Limit Limit > *PartNumber MHz MHz R1 R2 CpF k1 k2 k3 k4 k5 > * 026011F-561 1 1000 690 2.8 0.022 0.0001 0.239 0.584 0.0172 5e-007 > .SUBCKT 026011F_561 1 4 > .param R1 690 > .param R2 2.8 > .param C1 2.2e-014 > .param k1 0.0001 > .param k2 0.239 > .param k3 0.584 > .param k4 0.0172 > .param k5 5e-007 > R2 1 2 {R2} > R1 3 4 {R1} > C1 2 3 {C1} > Grv1 2 5 2 5 LAPLACE={1/(k1*sqrt(1 + s/(2*pi))) } > R98 2 5 1G > GLv1 5 4 5 4 LAPLACE={1/(1e-3 + s*1e-6*(k3 - (k4*LOG(k5*(s/(2*pi)))))) } > R99 5 4 1G > Grv2 2 4 2 4 LAPLACE={1/(k2*sqrt(1 + s/(2*pi))) } > .ENDSThanks to each of you for clarifying my doubts and reinforcing my own ideas on this very interesting topic. I agree that SPICE small signal(.AC) feature is good only for S parameters measurement at start up, and that too when pesky things like frequency dependent resistors. Also, my inductors are etched on a PCB, or on SiO2.

Reply by ●November 20, 20212021-11-20

On Fri, 19 Nov 2021 22:21:27 -0800 (PST), whit3rd <whit3rd@gmail.com> wrote:>On Friday, November 19, 2021 at 7:16:58 AM UTC-8, jla...@highlandsniptechnology.com wrote: >> On Fri, 19 Nov 2021 03:59:40 -0800 (PST), amal banerjee >> <daku...@gmail.com> wrote: >> >> >Could some electronics suru here clarify this a bit ? >> >A planar inductor has a frequency dependent resistance(skin, proximity effecrs). Can the small signal S parameters for such an inductor be measured using stabdard SPICE small signal(.AC) analysis ? >> >At each frequency in a specified frequency range, the series resistance is different. Does this new resistance at each frequency have effect on the S >> >parameter estimation. > >> Like these? >> >> https://www.dropbox.com/s/u4yiv4p0ho2ktu4/1010VS_pair.JPG?raw=1 >> >> I've smoked these in a pulse application, at way below rated RMS >> current. Skin loss! I had to wind my own, which I hate to do. > >Oh, that's just the tip of the iceberg. In pulse applications, there's >mechanical stress to consider. as well. This little item, for instance, >had a mechanical stress event > ><http://www.capturedlightning.com/frames/gallery/coins6.jpg> > >and no amount of SPICE expertise can model that issue.That inductor sees 7 ns 1400 v pulses at up to 5 MHz. So there are no mechanical effects. Or no audible ones! -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.