0
\$\begingroup\$

I am new to antenna theory, and I have been reading up on antenna properties to create my own antenna.

I want to use a piece of copper wire, maybe around 18 gauge, as a monopole antenna, but it will also be electrically short, at least less than lambda/10.

Furthermore, the antenna will be designed for a single frequency.

Other than the fact that electrically short antennas have a high input reactance, I can't find any information on how to calculate the radiation resistance of a straight, round wire without using a network analyzer. Does anybody know of any information or software I could use to calculate this radiation resistance for impedance matching? Thanks!

\$\endgroup\$
  • \$\begingroup\$ This is beyond my own expertise, but I know that the ARRL Antenna Book (my copy is ancient) has not just a lot of theory, but also a lot of practical information on how to match impedances, check SWR, etc. arrl.org/shop/ARRL-Antenna-Book-22nd-Edition \$\endgroup\$ – mickeyf_supports_Monica Sep 15 '12 at 3:32
  • \$\begingroup\$ @mickeyf Thanks, I saw that the latest edition has chapters on space limited antennas and portable antennas. \$\endgroup\$ – Ag565 Sep 15 '12 at 5:42
  • \$\begingroup\$ Do you have to use a monopole for this? There are much better approaches for electrically-short scenarios (all of which are basically clever ways of being less "short" in the same volume). For example, the Folded Unipole Antenna (FUA). If you only need narrow-band operation then you have lots of awesome options. What frequency (just curious)? \$\endgroup\$ – DrFriedParts Mar 29 '13 at 5:51
1
\$\begingroup\$

A monopole antenna have a varying radiation resistance according to the ground plane size. You can use a series coil to eat up the capacitive parts of a short monopole and you would get a pretty good match with a 50ohm receiver front-end.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.