[SI-LIST] Re: [SI-LIST]modelling of wire as w element transmission line

Dear Tetsuhisa,
              You are correct in both points. After getting reply from you and 
Ray I looked into the file and found that the width of the strip was beg enough 
to overlap for model1. While I tried to run it again using hspice 2000.4 in 
solaris, it gave error that strip conductor is not supported. I will try the 
rectangle one and see.
Thank you.
Jayanta
>To: jxc9551@xxxxxxxxxxxxxxxxxx
>Cc: "si list" <si-list@xxxxxxxxxxxxx>
>Subject: Re: [SI-LIST] modelling of wire as w-element transmission line
>Mime-Version: 1.0
>Content-Transfer-Encoding: 7bit
>Date: Tue, 25 Jun 2002 12:22:23 -0700 (PDT)
>From: Ted Mido <Tetsuhisa.Mido@xxxxxxxxxxxx>
>X-Dispatcher: imput version 20000228(IM140)
>X-Keywords: 
>
>
>Dear Jayanta,
>
>I had a quick look at your field solver structure.
>
>One thing which is not clear to me is, the model statement
>of 'mymodel1.'
>
>.MODEL mymodel1 W MODELTYPE=FieldSolver LAYERSTACK=mystack FSOPTIONS=myoption 
>+ RLGCFILE=test4.rlgc OUTPUTFORMAT=RLGCFILE CONDUCTOR=( SHAPE=myshape1, 
>+ ORIGIN=(1000, 3000), MATERIAL=mymetal), ( SHAPE=myshape2, ORIGIN=(1050, 
3000), MATERIAL=mymetal)
>
>If I look at the 'W1' statement this model statement
>for 2 conductors should be
>
>.MODEL mymodel1 W MODELTYPE=FieldSolver LAYERSTACK=mystack FSOPTIONS=myoption
>+ RLGCFILE=test4.rlgc OUTPUTFORMAT=RLGCFILE
>+ CONDUCTOR=( SHAPE=myshape1, ORIGIN=(1000, 3000), MATERIAL=mymetal)
>+ CONDUCTOR=( SHAPE=myshape2, ORIGIN=(1050, 3000), MATERIAL=mymetal)
>
>but still, these 2 conductors are overlapped together.
>It seems that the metal conflict is causing a problem in
>the solver.
>
>
>In addition to this, here are some comments on it.
>
>1. It would be better to use 'rectangle' instead of strip with 
>adding height of the conductor? Skin effect solver doesn't support
>'strip' shape since we cannot define 2D mesh structure from it.
>
>2. It would be better to begin the exam with smaller number 
>of mesh (N or NH/NW). I believe N=20-30 should be able to give 
>you relatively good result for this structure. 
>
>3. It would be better to use 2001.2 or later with specifying 
>copper reference plane in the layer stack? I believe this way takes
>the return current distribution better.
>
>best regards,
>
>
>       ted@synopsys
>
>
>
>From: Jayanta Choudhury <jxc9551@xxxxxxxxxxxxxxxxxx>
>Subject: [SI-LIST] modelling of wire as w-element transmission line
>Date: Tue, 25 Jun 2002 11:56:10 -0500 (CDT)
>
>> Hi,
>>     I want to model a wire or metal, used in the metal layers of semi 
conductor 
>> substrate preferably CMOS or GaAs high-speed circuits, in hspice 2000.4. The 
>> purpose  to study signal corruption and distortion during the signal 
propagation 
>> thru the interconnects. I am using the W-element transmission line model for 
>> this and FSModel with SHAPE of metal as "strip". I want to see the waveforms 
in 
>> the situation described below.
>>   1. Two transmission lines with multiple conductor passing accross each 
other.
>>   2. Two transmission lines are at different heights 
>>   3. Both of them has same reference ground for near-end and far-end 
terminals,
>>      which is the bottom of the substrate.
>>   the top view is some what similar to what is shown below.
>>   
>>   
>>              |       |
>>   --------------|-------|---------------------
>>              |       |
>>   --------------|-------|---------------------
>>              |       |
>>              |       |
>>              
>> If I model the longer lines with z-axix along their length, y-axis along 
their 
>> height and width along the x-axis I cannot model two conductors of the 
>> transmission line with shorter conductors. I can have only one conductor of 
that 
>> by having its width eqaul to the size of the actual length of the shorter 
>> conductor in strip SHAPE statement and length equal to actual width. But the 
>> spice file keeps running in an infinite loop.
>> 
>> The spice file is attached.
>> 
>> If any one has any clue to this please help me.
>> Thank you.
>> Jayanta Choudhury
>> 
>> 
>> -- Attached file included as plaintext by Ecartis --
>> -- File: across_lines.spice
>> -- Desc: across_lines.spice
>> 
>> *example. for observing two transmission lines lengths spreading accross 
>> each 
other
>> 
>> .OPTION scale=0.1u
>> .OPTION POST
>> 
>> **a piece wise linear input waveform is used to model a step input
>> v1 in1 GND pwl 5n 0v 5.06n sp, 14.94n sp, 15.0n 0v
>> **V1 in1 gnd PULSE (0 5 2NS 0NS 0NS 50NS 100NS)
>> **V1 in1 gnd SIN (0 5 1MEG)
>> 
>> **W type transmission line state ment with driver side in1 and gnd and 
reciever side
>> ** out1 and ground, Field Solver(FSmodel) model is defined below, number of 
conductors
>> ** is N=2 length of the strip is l=25*scale(0.1um)
>> W1 out00 out01 gnd in00 in01 gnd FSmodel=mymodel1 N=2 l=25000
>> W2 out10 gnd in10 gnd FSmodel=mymodel2 N=1 l=500
>> 
>> **Output Capacitance
>> C1 out00 gnd 10fF
>> c2 out01 gnd 10fF
>> C3 out10 gnd 10fF
>> 
>> 
>> 
>> 
>> .PARAM sp=3.3v 
>> 
>> **Model for solving equations and calculating RLGC values and writing them 
>> in 
RLGC 
>> **file specified by OUTPUTFORMAT, RLGCFILE is the file name ORIGIN is the 
co-ordinates 
>> **of strip MATERIAL is the metal for the conductor
>> .MODEL mymodel1 W MODELTYPE=FieldSolver LAYERSTACK=mystack 
>> FSOPTIONS=myoption 
>> + RLGCFILE=test4.rlgc OUTPUTFORMAT=RLGCFILE CONDUCTOR=( SHAPE=myshape1, 
>> + ORIGIN=(1000, 3000), MATERIAL=mymetal), ( SHAPE=myshape2, ORIGIN=(1050, 
3000), MATERIAL=mymetal)
>> 
>> **Model for solving equations and calculating RLGC values and writing them 
>> in 
RLGC 
>> **file specified by OUTPUTFORMAT, RLGCFILE is the file name ORIGIN is the 
co-ordinates 
>> **of strip MATERIAL is the metal for the conductor
>> .MODEL mymodel2 W MODELTYPE=FieldSolver LAYERSTACK=mystack 
>> FSOPTIONS=myoption 
>> + RLGCFILE=test5.rlgc OUTPUTFORMAT=RLGCFILE CONDUCTOR=( SHAPE=myshape2, 
>> + ORIGIN=(0, 5000), MATERIAL=mymetal)
>> 
>> 
>> **mymetal has the characteristics of copper
>> .MATERIAL mymetal METAL CONDUCTIVITY=57.6meg
>> 
>> **dielectric has the characteristic of some example dielectric from manual
>> .MATERIAL mydiel DIELECTRIC LOSSTANGENT=1.2e-3
>> 
>> **Shape is Strip with width 1 micron and N=100 is number of discretization
>> .SHAPE myshape1 STRIP WIDTH=500 N=100
>> 
>> .SHAPE myshape2 STRIP WIDTH=25000 N=5000
>> 
>> **LAYERSTACK is the stack of dielectric or metal layers associated with 
transmission 
>> **line, here it is a stack of default type metal named PEC and a dielectric 
>> ** specified by Material is background and thickness of PEC is 5um
>> .LAYERSTACK mystack BACKGROUND=mydiel LAYER=(PEC, 5), LAYER=(mydiel, 5095)
>> 
>> **Options for Field Solver model is defined GRIDFACTOR, which is multipled 
with 
>> **number of discretization specified in shape, PRINTDATA to print the datas
>> **COMPUTEGD to calculate the conductance matrix Gd for rotation of dipoles 
under
>> **the influence of alternating electric field, COMPUTERS computes skin 
>> effect 
>> **Resistance matrix Rs
>> .FSOPTIONS myoption ACCURACY=HIGH GRIDFACTOR=1 PRINTDATA=YES COMPUTEGD=YES 
>> + COMPUTERS=YES
>> 
>> 
>> .TRAN 0.01n 1000n
>> .end
>> 
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