µwave filter design (help needed)
 

hello,
i am a student and we got a hf task for a lab project. we have to
built a low pass filter (-3dB @ 500MHz, 3th order) in microstrip,
coupled lines and interdigital. the first two we have to build and
measure, the 3th one is to calculate only. i know the last two filters
are band pass, but we should design something with highest brakepoint
at 500MHz.

now my question:
we managed to calculate the microstrip filter so that one is done and
simulated. what botters us is that we didn't get ANY sort of a course
(we have to find anything on our own) and we have no clue about the
coupled lines and even less about the interdigital filter.
there is very very little useful information to find on the web so
please can someone help me here by giving some basic
methodology/formulas for coulpled lines or interdigital filters. maybe
someone has a few pdf's or other info on his harddisk he/she could
send me?

thanks in advance
lenx

Lenx wrote:
we managed to calculate the microstrip filter so that one is done and
simulated. what botters us is that we didn't get ANY sort of a course
(we have to find anything on our own) and we have no clue about the
coupled lines and even less about the interdigital filter.

What books does your course use? Pozar's "Microwave Electronics" book (or
perhaps "Microwave and RF Design of Wireless Systems" -- there's some
overlap between the two with the later typically being less theoretical and
more applications oriented) is the one that immediately comes to mind for
your problem.

---Joel Kolstad

Lenx wrote:
we managed to calculate the microstrip filter so that one is done and
simulated. what botters us is that we didn't get ANY sort of a course
(we have to find anything on our own) and we have no clue about the
coupled lines and even less about the interdigital filter.

What books does your course use? Pozar's "Microwave Electronics" book (or
perhaps "Microwave and RF Design of Wireless Systems" -- there's some
overlap between the two with the later typically being less theoretical and
more applications oriented) is the one that immediately comes to mind for
your problem.

---Joel Kolstad

Laura Halliday wrote:
Why are you only looking on the web? Does your school
not have a library?

He's probably looking because the web tends to be more efficient in its
searches than any library (i.e., Google searches the contents of web pages
themselves, whereas libraries are only able to search via titles or
sometimes summaries) and also because the web tends to be have its eye a
little more bent towards practical applications rather than strictly
theoretical concerns (something that libraries are filled with!). Of
course, I'd never suggest a library isn't a wonderful resource as well, just
giving you some insight from someone who's spent plenty of time in both.

There are zillions of papers on the subject out there.

Yes, but unless he uncovers one that's specifically meant to be a review of
well-known subjects or tutorial in nature (such papers do of course exist,
but they're few and far between given that most professional journals are
aimed at publishing new research), he'll be wasting his time since it's
clear he needs some pretty introductory material at this point.

Sorry if this sounds unkind, it's just that a lot of students I know have
wasted tons of time trying to understand journal articles when what they
really need is a good textbook.

I do like your suggestion to check out some of the trade magazines such as
RF Design, however!

---Joel Kolstad

Laura Halliday wrote:
Why are you only looking on the web? Does your school
not have a library?

He's probably looking because the web tends to be more efficient in its
searches than any library (i.e., Google searches the contents of web pages
themselves, whereas libraries are only able to search via titles or
sometimes summaries) and also because the web tends to be have its eye a
little more bent towards practical applications rather than strictly
theoretical concerns (something that libraries are filled with!). Of
course, I'd never suggest a library isn't a wonderful resource as well, just
giving you some insight from someone who's spent plenty of time in both.

There are zillions of papers on the subject out there.

Yes, but unless he uncovers one that's specifically meant to be a review of
well-known subjects or tutorial in nature (such papers do of course exist,
but they're few and far between given that most professional journals are
aimed at publishing new research), he'll be wasting his time since it's
clear he needs some pretty introductory material at this point.

Sorry if this sounds unkind, it's just that a lot of students I know have
wasted tons of time trying to understand journal articles when what they
really need is a good textbook.

I do like your suggestion to check out some of the trade magazines such as
RF Design, however!

---Joel Kolstad

"Joel Kolstad" wrote in message ...
Laura Halliday wrote:
Why are you only looking on the web? Does your school
not have a library?

He's probably looking because the web tends to be more efficient in its
searches than any library (i.e., Google searches the contents of web pages
themselves, whereas libraries are only able to search via titles or
sometimes summaries) and also because the web tends to be have its eye a
little more bent towards practical applications rather than strictly
theoretical concerns (something that libraries are filled with!). Of
course, I'd never suggest a library isn't a wonderful resource as well, just
giving you some insight from someone who's spent plenty of time in both.

Thanks for the words-of-one-syllable-or-less explanation.
If the information isn't on the web, no search engine is
going to find it.

There are zillions of papers on the subject out there.

Yes, but unless he uncovers one that's specifically meant to be a review of
well-known subjects or tutorial in nature (such papers do of course exist,
but they're few and far between given that most professional journals are
aimed at publishing new research), he'll be wasting his time since it's
clear he needs some pretty introductory material at this point.

Sorry if this sounds unkind, it's just that a lot of students I know have
wasted tons of time trying to understand journal articles when what they
really need is a good textbook.

The ARRL and RSGB have published numerous books on
microwave stuff. Not only does the material tend to be
at a very practical nuts and bolts level, the references
tend to be pretty good. There are lots of others,
thugh the specialist journals like VHF Communications/
UKW-Berichte and DUBUS tend to be hard to come by.

What makes you think I don't know what being a student
is like? I'd hate to think I wasted such an obscene
amount of money on my B.Sc. and M.A.Sc. degrees. I
completed the latter in 2000, and the Internet was an
important tool. But it wasn't my *only* tool. Anybody
who thinks it is is either naive or stupid.

Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte

"Joel Kolstad" wrote in message ...
Laura Halliday wrote:
Why are you only looking on the web? Does your school
not have a library?

He's probably looking because the web tends to be more efficient in its
searches than any library (i.e., Google searches the contents of web pages
themselves, whereas libraries are only able to search via titles or
sometimes summaries) and also because the web tends to be have its eye a
little more bent towards practical applications rather than strictly
theoretical concerns (something that libraries are filled with!). Of
course, I'd never suggest a library isn't a wonderful resource as well, just
giving you some insight from someone who's spent plenty of time in both.

Thanks for the words-of-one-syllable-or-less explanation.
If the information isn't on the web, no search engine is
going to find it.

There are zillions of papers on the subject out there.

Yes, but unless he uncovers one that's specifically meant to be a review of
well-known subjects or tutorial in nature (such papers do of course exist,
but they're few and far between given that most professional journals are
aimed at publishing new research), he'll be wasting his time since it's
clear he needs some pretty introductory material at this point.

Sorry if this sounds unkind, it's just that a lot of students I know have
wasted tons of time trying to understand journal articles when what they
really need is a good textbook.

The ARRL and RSGB have published numerous books on
microwave stuff. Not only does the material tend to be
at a very practical nuts and bolts level, the references
tend to be pretty good. There are lots of others,
thugh the specialist journals like VHF Communications/
UKW-Berichte and DUBUS tend to be hard to come by.

What makes you think I don't know what being a student
is like? I'd hate to think I wasted such an obscene
amount of money on my B.Sc. and M.A.Sc. degrees. I
completed the latter in 2000, and the Internet was an
important tool. But it wasn't my *only* tool. Anybody
who thinks it is is either naive or stupid.

Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte

Laura Halliday wrote:


What makes you think I don't know what being a student
is like? I'd hate to think I wasted such an obscene
amount of money on my B.Sc. and M.A.Sc. degrees. I
completed the latter in 2000, and the Internet was an
important tool. But it wasn't my *only* tool. Anybody
who thinks it is is either naive or stupid.

Laura Halliday

I agree with you. That's why I have a library of reference and data
books that fills a small bedroom in my house. A couple thousand books,
the list time I tried to get a full count. ;-)
--
25 days!


Michael A. Terrell
Central Florida