[SI-LIST] Re: [SI-LIST]modelling of wire as w element transmission line
- From: Jayanta Choudhury <jxc9551@xxxxxxxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Wed, 26 Jun 2002 10:37:43 -0500 (CDT)
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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