Thanks, Harrison and Gene,
Actually this product is going to be deployed in about three months
time in one of our public sectors. And it really gives me and my boss
nightmare every night. For small company like us, there is no choice
but to grab everything we could to deliver.
The original prototype is well designed and tested. the frequency is
433 m. Therefore quarter wave length would be about 17.2 cm, which
would be too long for a commercial handheld product.
Our task is to re-package it and produce. And that is why i need to
modify the antenna. I tested quite a few antennas including loop,
semiloop, modified dipole and microstrip antenna as given in
http://www.rfm.com/corp/appdata/antenna.pdf
I am using copper fold to make the antenna plane and the groundplane.
However, the results is far from satisfactory.
For the above mentioned antennas, i did not changed the matching
network given in the transferred design which caters for 17.2 cm
antenna. Do i need to do so? Thanks.
Sigma montoya

Sigma

Yageo sells a $2.00 ceramic antenna for circuit board mount for 433 that
you probably already know about. Contact me if you want any info about how
to get that antenna.

Jerry


"Montoya" wrote in message
om...
Thanks, Harrison and Gene,
Actually this product is going to be deployed in about three months
time in one of our public sectors. And it really gives me and my boss
nightmare every night. For small company like us, there is no choice
but to grab everything we could to deliver.
The original prototype is well designed and tested. the frequency is
433 m. Therefore quarter wave length would be about 17.2 cm, which
would be too long for a commercial handheld product.
Our task is to re-package it and produce. And that is why i need to
modify the antenna. I tested quite a few antennas including loop,
semiloop, modified dipole and microstrip antenna as given in
http://www.rfm.com/corp/appdata/antenna.pdf
I am using copper fold to make the antenna plane and the groundplane.
However, the results is far from satisfactory.
For the above mentioned antennas, i did not changed the matching
network given in the transferred design which caters for 17.2 cm
antenna. Do i need to do so? Thanks.
Sigma montoya

Thanks, Jerry.
How can make a 50 ohm semi-loop antenna as stated in the link
http://www.rfm.com/corp/appdata/antenna.pdf

"Montoya" wrote in message
om...
Thanks, Jerry.
How can make a 50 ohm semi-loop antenna as stated in the link
http://www.rfm.com/corp/appdata/antenna.pdf

Sigma

Although I am confidant that I could design and build an antenna from the
above sited antenna concept, I have way too litle knowledge of your
restrictions. If you did want to get some help with this antenna maybe you
could write a more difinitive description of your needs and restrictions for
the really good antenna guys who read this antenna news group.
If your "specs" are realistic, I'd bet money that even I could design a
satisfactory "semi-loop", and I might be one of the least prepared antenna
designers who frequent this site.

Jerry