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Microstrip Filter Design - RF Cafe Forums

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Rising_Phoenix
Post subject: Microstrip Filter Design Posted: Wed Jul 11, 2007 6:05 am

Lieutenant


Joined: Wed Jul 11, 2007 5:54 am
Posts: 3
Hello everyone. I am trying to learn how to design a microstrip filter. I have already made a simple lumped-element design of a band pass filter and I am trying to transform it into a microstrip filter. I have no idea where to start from. I am not an RF engineer but I am doing some research on my own and have learned the basics of electromagnetics and using the Smith Chart to calculate line impedances. I also have a couple of calculators to design microstrip widths and lengths in order to get a microstrip with a certain characteristic impedance. Can anyone please direct me to some tutorials on how to replace a lumped capacitor, for instance, with a microstrip, and the things I need to take into consideration in order to connect the capacitors and inductors together and have them matched. I would rather start with basic techniques of drawing microstrip PCBs then move to interdigital filters and comb line ones.

Your assistance is much appreciated.


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Jeanalmira
Post subject: Posted: Thu Jul 12, 2007 12:00 am

General


Joined: Tue Mar 15, 2005 11:43 pm
Posts: 65
Location: Singapore
Hi Rising_Phoenix,

Realizing microstrip element from lumped elements is not that hard, with the help of software. I am not sure what software you are using. For example, Microwave Office AWR has a tool called "TX Line" which enable you to convert any impedance to microstrip line.
and I believe there's a freeware from HP called AppCAD :
http://www.hp.woodshot.com/

First thing you have to do is, calculate the impedance of each element at your frequency range (for example, in mag / angle), then put the value in the software and angle to the electrical length).

and fill the substrate parameters, such as dielectric constant, tangent loss, substrate thickness, etc.

I believe you'll be able to convert to the microstrip line parameters, such as length and width (on the specified substrate).

Just to take note that, impedance magnitude will refer to width of mstrip line, while length will refer to the angle.

I hope it helps.

Regards,
Jean Almira
Wavestream Corp
Singapore


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imodelit_moderator
Post subject: Microstrip Filter DesignPosted: Sat Jul 14, 2007 12:55 pm

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear Rising_Phoenix,

Check these online tools. http://imodelit.com/ViewProducts.aspx?CID=98

Best Regards,
imodelit Moderator


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karthik
Post subject: Posted: Sun Jul 15, 2007 3:37 pm

Colonel

Joined: Tue Apr 11, 2006 8:13 pm
Posts: 34
Hi,

The book by Pozar, Microwave Engineering, has a detailed design approach to go from lumped element to a microstrip filter


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nubbage
Post subject: Posted: Mon Jul 16, 2007 8:37 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
imodelit failed to run the applet for me.
Does it work for youz all?
I have this effect on technology 8:(


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imodelit_moderator
Post subject: Posted: Tue Jul 17, 2007 1:58 am

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear nubbage,

Could you please give me more details about why the applets did not run? As a first trial, please check that you have updated the JVM on your PC. The applets have to run on any platform.

Waiting to hear from you soon. Thanks.

Best Regards,
imodelit Moderator


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nubbage
Post subject: Posted: Tue Jul 17, 2007 3:29 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
JVM?
The front-end reaches the RUN stage and when I click on RUN, it just gives me a grey screen, with a red X at the top left hand corner. I guess the Java Runtime Environment s/w needs a tweak or an update?
IE version is at least 6.0
The terminal I use is connected on a corporate network, so software downloads are a no-no, blocked by the IT dept.
I clicked "yes" to the "Trust?" query page, but as I say, the Run does not even crawl.


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imodelit_moderator
Post subject: Posted: Wed Jul 18, 2007 10:21 pm

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear nubbage,

Kindly, check the JVM version. The applets need at least version 1.5. Waiting for reply. Thanks.

Best Regards,
imodelit Moderator


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nubbage
Post subject: Posted: Thu Jul 19, 2007 3:48 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
JVM??


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imodelit_moderator
Post subject: Posted: Thu Jul 19, 2007 7:38 am

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear nubbage,

Please, re-identify your problem? Have you updated the JVM?

Best Regards,
imodelit Moderator


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nubbage
Post subject: Posted: Thu Jul 19, 2007 8:54 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
Hi imodelit
My biggest problem is I do not have a clue what a JVM is.
When I know that, I don't know what I need to do to update it.
I have a company terminal here, super-wizzard-latest TOTR, but the IT dept do not allow random downloads etc.
For my symptoms, please see previous posting - the RUN button does nothing.
Thanks
nubbage


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karthik
Post subject: Posted: Thu Jul 19, 2007 3:40 pm

Colonel

Joined: Tue Apr 11, 2006 8:13 pm
Posts: 34
Hi Nubbage,

Java Runtime Environment and JVM (Java Virtual Machine) are pretty much the same......


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karthik
Post subject: Posted: Thu Jul 19, 2007 3:42 pm

Colonel

Joined: Tue Apr 11, 2006 8:13 pm
Posts: 34
I take it back...they arent exactly the same...but JRE is a specific implementation of JVM

Karthik


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imodelit_moderator
Post subject: How to get JREPosted: Fri Jul 20, 2007 1:43 pm

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear nubbage
You can get it for free from http://java.com/en/download/index.jsp

If the problem persists, please don't hesitate to contact us at customer.support@imodelit.com. We are at your disposal.

Regards
imodelit moderator


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Rising_Phoenix
Post subject: Posted: Sat Jul 21, 2007 5:25 am

Lieutenant


Joined: Wed Jul 11, 2007 5:54 am
Posts: 3
Hello. Thanks a lot for the help but the applets are refusing to run! I keep getting a Java error although I had it installed. What should I do? And do you know of any other similar applets? Thanks a lot.


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imodelit_moderator
Post subject: Posted: Sat Jul 21, 2007 9:31 am

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear Rising_Phoenix,

Could you please send me snapshot of the error you get? Thanks.

Best Regards,
imodelit Moderator


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Rising_Phoenix
Post subject: Posted: Sat Jul 21, 2007 1:14 pm

Lieutenant


Joined: Wed Jul 11, 2007 5:54 am
Posts: 3
Well yeah sure except I'm not sure how to attach the image using '[img]'.%20Could%20you%20please%20tell%20me?%20%20[/img]


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imodelit_moderator
Post subject: Posted: Sat Jul 21, 2007 3:38 pm

Captain


Joined: Wed Jun 20, 2007 3:01 am
Posts: 22
Dear Rising_Phoenix,

Could you please send it directly on this email, customer.support@imodelit.com ? Thanks.

Best Regards,
imodelit Moderator


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Antonio
Post subject: Posted: Mon Jul 23, 2007 3:19 am

Captain


Joined: Sat Jun 16, 2007 12:26 am
Posts: 12
Hi all,
If Rising_Pheonix is going to design a bandpass filter using coupled lines in microstrip then I think that AppCAD will not help him to find the dimensions of the lines and spacing between the lines. For this he has to use some other software.






Posted  11/12/2012
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