Darshan, An excellent book on field solvers is: Daniel Swanson, Wolfgang Hoefer: Microwave Circuit Modeling using Electromagnetic Field Simulation. Artech House, 2003. Regards, Istvan Novak SUN Microsystems Darshan Mehta wrote: >Steve, > > > >Now I understood why calculation does not give correct answer and field >solvers are used for Impedance calculation. > > > >Could you please tell me which book I should refer to know more about “How the >field Solver works”, I am really keen to know about field solvers. > > > >Thanks, > >Darshan Mehta > > >steve weir <weirsi@xxxxxxxxxx> wrote: >Darshan, please read Dr. Bogatin's book thoroughly. He demonstrates: > >1. That all closed form formulas for wave guide impedance are approximations >with limited accuracy over finite ranges. >2. Line to line coupling for several configurations. >3. That to get a really accurate answer you need to use a field solver. > >Steve. >At 12:24 AM 8/5/2005 -0700, Darshan Mehta wrote: > >Steve and Abhijit,<?xml:namespace prefix = o ns = >"urn:schemas-microsoft-com:office:office" /> > > > >Once again Thanks for clarifying my doubts. > > > >The formula for Capacitance calculation for Stripline configuration is as >follows (pF/inch); > > > >C = 1.4 * Er / ln [ 2.4 * (b / w)] > > > >Where b = total height of Dielectric between the Plane Layer and w is the >width of Trace. > > >Generally we take the height between the Plane layers (return current path) as >the b in the capacitance calculation. But as per your mail if the nearby >conductors also act as a return current, what dielectric height I should >consider while calculating the Capacitance. > >Thanks, > >Darshan Mehta > > > > >steve weir <weirsi@xxxxxxxxxx> wrote: > Darshan, Abhijit, I find Dr. Bogatin's book "Signal Integrity Simplified" > is an excellent text that presents the material clearly without losing > technical accuracy. It belongs right up there with other excellent books > such as those by Dr. Johnson, Dally & Poulton, Young, and Hall. And I am > not just saying that because it features Teraspeed's development of "Final > Inch" for Samtec. > > > Abhijit is correct. Any conductor is a better wave guide than > dielectric. Either provide conductors to supply the return path by > intention, or your signals will find other conductors on their own. > > > Steve. > At 11:53 PM 8/4/2005 -0700, Abhijit Mahajan wrote: > >Darshan > > > >Nearby signals traces can also act as return path. One possible way to > >improve return path situation (on two layer boards) is to use coplanar > >waveguide configuration. It can be useful for two layer boards having = > >high > >speed traces, and also when the board thickness is on the higher side.=20 > > > >BTW, I haven't read this book but it certainly sounds like a good one = > >since > >it got you thinking so much on return currents! > > > >Abhijit. > >=20 > > > >-----Original Message----- > >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = > >On > >Behalf Of Darshan Mehta > >Sent: Friday, August 05, 2005 11:35 AM > >To: steve weir; si-list@xxxxxxxxxxxxx > >Subject: [SI-LIST] Re: Return Path > > > >Steve, > > > >=20 > > > >Thanks for the reply.=20 > > > >=20 > > > >So you mean to say that if we don't have Plane Layer, the Electric and > >Magnetic field will be coupled to the nearby conductor. If we have a = > >Plane > >layer also present on the board, does the nearby conductor act as a = > >Return > >path? My basic question is, on what basis we should think that this = > >conductor > >will act as a return path for given signal. If the Plane shape is = > >present on > >the board, does the Plane as well as the nearby conductors will act as a > >return current or only the Plane shape will act like return current = > >path.=20 > > > >=20 > > > >Thanks, > > > >Darshan Mehta > > > > > >steve weir wrote: > >Darshan, if you have a board with no dedicated plane, then the fields = > >will > >just spread out, coupling the signal into multiple conductors. A field = > >solver > >can determine the coupling on each line for a given configuration. > > > >Steve. > >At 10:31 PM 8/4/2005 -0700, Darshan Mehta wrote: > > >Hello Experts, > > > > > > > > > > > >I have a question on return current. I was going through the book=20 > > >"Signal Integrity Simplified" and came to know that return current path > = > > > > >can be a Power Plane or Ground Plane. I am still confused about > return=20 > > >path. Let me describe what I understood. > > > > > > > > > > > >The Signal Path is the active path and the Electric field from Signal=20 > > >will terminate in the return path. The Magnetic field will form a=20 > > >circular loop around the signal and it will be coupled with return path > = > > > > >so that equal and opposite current will flow in return path. Normally=20 > > >if we have Power Plane or Ground place, the return path will be easy to > = > > > > >find out. Let's assume, if we have a 2 layer board with no copper shape > = > > > > >drawn on it, how to find the return path for the signal? Please help me > >understanding this. > > > > > > > > > > > >Thanks, > > > > > >Darshan Mehta > > > > > ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu