Hi Scott, Is there any documentation of a study which demonstrates this particular effect? Jeff Loyer -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Scott McMorrow Sent: Friday, May 10, 2013 11:59 AM To: orphanou@xxxxxxxxxxxx Cc: bradb@xxxxxxxxxxx; leeritchey@xxxxxxxxxxxxx; dennis.han@xxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: anti-resonance point when use Embedded Capacitance Material antonis Sure radiating edges are a problem. Ever seen a cable routed adjacent to the edge of a PCB in a chassis? Most radiation problems occur when external antennas (cable shields, metal patches, package metal lead frames and planes) couple resonances elsewhere. On Fri, May 10, 2013 at 2:39 PM, Antonis Orphanou <orphanou@xxxxxxxxxxxx>wrote: > Is edge fringing a real concern here? The dielectric to air interface > is highly reflective after all ..... > The first order radiation mechanism is image currents from resonating > planes (and patch antenna concepts as earlier mentioned). > An ideal capacitor array is like an EM wall that splits the power > plane into smaller sections hence shifting the radiated spectrum and > resonance frequencies higher up in spectrum. Can a realistic > capacitor and its inductance achieve that task? Judging from earlier > responses that sounds impossible.... > > > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx > [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of Bradley Brim > Sent: Friday, May 10, 2013 11:16 AM > To: leeritchey@xxxxxxxxxxxxx; dennis.han@xxxxxxxxx; > si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: anti-resonance point when use Embedded > Capacitance Material > > Hi Lee, > Plane pair cavity resonances contribute to emissions. The earliest > power integrity experts seem to have been EMC engineers concerned less > with PDN noise at devices and more concerned with reducing emissions from the > PDN. > One can even view the operation of a microstrip patch antenna as a > form of plane pair resonance and its sole purpose is to send/receive > radiated emissions. > > To address a topic of the original inquiry ... > Smaller plane separation implies less area of equivalent magnetic > current at the plane pair edge, or equivalently less local fringing > field volume, and therefore lower emissions for a given field > strength. However, the smaller the plane separation the higher the Q > of the cavity can be, implying a higher field strength at the plane pair > edges. > > At frequencies where the sum of mounting inductance and ESL for the > cap do not combine to make them exceedingly high impedance they will > certainly affect plane resonances, whether or not placed in a uniform > or grid pattern. EMC engineers typically guide for a uniform/grid > placement with spacing based on a fraction of the wavelength in the > cavity material at the highest frequency of concern. I observe PI > experts with access to simulation tools approach the issue by > visualizing PDN cavity resonances and placing caps near > voltage/impedance maxima. This may not eliminate all resonances and > can serve to shift the resonances to other frequencies. An iterative > process of analyzing and cap placement is pursued. I've seen cases > where this can yield as many or more caps than a uniform/grid > placement. A procedure to consider simultaneous placement of all > required "emicaps" (rather than the iterative process that does not > reexamine selection/placement from previous iterations) can yield > significantly fewer caps for the same level of emissions. > > Best regards, > -Brad > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx > [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of Lee > Sent: Friday, May 10, 2013 9:16 AM > To: dennis.han@xxxxxxxxx; si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: anti-resonance point when use Embedded > Capacitance Material > > I have seen no evidence that plane resonances contribute to EMI or > that distributing capacitors evenly over a plane has much effect on > resonances. > I do this so that there is an even distribution of "ground" vias > across the planes as has been recommended by Istvan. > > -----Original Message----- > From: Dennis > Sent: Friday, May 10, 2013 7:09 AM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: anti-resonance point when use Embedded > Capacitance Material > > There are also free spreadsheet calculators from Altera, Xilinx, and > Terry Fox & Associates. KEMET Spice can be used for that purpose to some > extent. > > Dennis > > --- In si-list@xxxxxxxxxxxxxxx, Ken Wyatt <ken@...> wrote: > > > > Thanks Chas, > > I remember those days...things have progressed greatly. > > > > Do you, or the group, know of affordable simulation S/W (Ansoft, > > maybe?) that would simulate plane resonances? My limited budget > > won't support multi-G$ S/W, unfortunately. That would be pretty cool > > to be able to simulate that. I saw a recent demo of HyperLynx that was > > impressive. > > > > I know Istvan has several Excel calculators that will model PDN > > impedances. > > > > You coming to the Denver symposium this year? > > > > Cheers, Ken > > ___________________ > > Kenneth Wyatt > > Wyatt Technical Services LLC > > Woodland Park, CO > > ken@... > > Web Newsletter > > Connect with me on LinkedIn! > > > > On May 9, 2013, at 2:22 PM, Grasso, Charles wrote: > > > > > Hello Ken, > > > > > > When faced with large areas of pwb that have little or no > > > components, > it > > > used common practice for EMI guys to add lossy caps (the lossier > > > the > > > better) > > > to the planes in a regular pattern to minimize the effects of > > > plane resonance. With modern simulation tools, the resonant modes > > > of the planes can be simulated and caps added (in just the right > > > spot!) to reduce the effect. > > > > > > Chas > > > > > > -----Original Message----- > > > From: si-list-bounce@... [mailto:si-list-bounce@...] On Behalf Of > Istvan > > > Novak > > > Sent: Thursday, May 09, 2013 7:23 AM > > > To: Ken Wyatt > > > Cc: bruce@...; si-list@... > > > Subject: [SI-LIST] Re: anti-resonance point when use Embedded > > > Capacitance Material > > > > > > Ken, > > > Bypass capacitors with more lossy dielectrics do help somewhat, > > > but the dielectric loss shows up strongly in the ESR only at > > > frequencies much lower than the series resonance frequency, where > > > we usually dont need the higher ESR. Very lossy (and sloppy) > > > dielectrics, such as Z5U and Y5V are good for cheap consumer > > > electronics, but for professional circuits there are many > > > drawbacks and it is not the best thing to use them. Ceramic > > > capacitors with user-defined ESR are available from two of the > > > major capacitor vendors, so they can be used when we need the highest > > > performance and can afford the higher cost for these parts. > > > > > > Regards, > > > > > > Istvan Novak > > > Oracle > > > > > > > > > > > > > > > On 5/9/2013 9:00 AM, Ken Wyatt wrote: > > >> Hi Group & Bruce, > > >> > > >> I'm kind of a "newby" when it comes to SI, but am reading Lee > > >> Richey's books on the subject. > > >> > > >> One thing he recommends for PDN designs is the use of bypass > > >> capacitors with a more lossy dielectric (higher ESR), such as > > >> X5R, Z5U or Y5V, to dampen the anti-resonance. Would this be a > > >> reasonable thing to try? > > >> > > >> Ken > > >> ___________________ > > >> Kenneth Wyatt > > >> Wyatt Technical Services LLC > > >> Woodland Park, CO > > >> ken@... <mailto:ken@...> Web > > >> <http://www.emc-seminars.com> Newsletter > > >> <http://emc-seminars.us1.list-manage.com/subscribe?u?7f203d1f64dd > > >> 89f 06b0c3f5&id 0f29a904> Connect with me on LinkedIn > > >> <http://www.linkedin.com/in/kennethwyatt>! > > >> > > >> On May 9, 2013, at 5:16 AM, Istvan Novak wrote: > > >> > > >>> Hi Bruce, > > >>> > > >>> The anti-resonance between the static capacitance of planes and > > >>> inductance of bypass capacitors will always be present unless > > >>> you either match the plane impedance with the ESRs of capacitors > > >>> or overwhelm the antiresonance with MANY low-inductance bypass > > >>> capacitors. The antiresonance is present with any laminate > > >>> material, thin or thick. > > >>> When you use thin laminates (Embedded Capacitance Material), the > > >>> resonance magnitude and frequency both get lower with respect to > > >>> a thicker laminate. First you have to determine whether the > > >>> resonance causes a problem for power, signal integrity and EMI. > > >>> If you dont excite the resonance, you dont need to care. > > >>> > > >>> Regards, > > >>> > > >>> Istvan Novak > > >>> Oracle > > >>> > > >>> > > >>> > > >>> > > >>> On 5/9/2013 2:26 AM, Bruce wrote: > > >>>> Hi Expert > > >>>> > > >>>> > > >>>> We use Embedded Capacitance Material for better PDN and less > > >>>> capacitor component. According to PDN Simulation. We notice > > >>>> that is an anti-resonance point between capacitor and Plane. > > >>>> > > >>>> > > >>>> > > >>>> We can find that when use Embedded Capacitance Material. There > > >>>> are much better in most frequency but near anti-resonance point. > > >>>> > > >>>> > > >>>> > > >>>> In this case. We have to solution. > > >>>> > > >>>> 1. Try to reduce the anti-resonance point. We need many high > > >>>> frequency > > >>>> capacitor component. That is not good because we want to reduce > > >>>> the number of capacitor component. Our purpose is reduce 70% > > >>>> number of capacitor component. > > >>>> > > >>>> 2. Keep this anti-resonance point. That maybe have a risk if > > >>>> there is > > >>>> some noise by chance in this frequency > > >>>> > > >>>> > > >>>> > > >>>> How about your suggestion? Please let me know if my question is > > >>>> not clear enough. > > >>>> > > >>>> Thanks > > >>>> > > >>>> > > >>>> > > >>>> Best Regards, > > >>>> > > >>>> Bruce Wu > > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > List forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > List forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > -- Scott McMorrow Teraspeed Consulting Group LLC 16 Stormy Brook Road Falmouth, ME 04105 (401) 284-1827 Business http://www.teraspeed.com Teraspeed(r) is the registered service mark of Teraspeed Consulting Group LLC ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu