antenna-theory.com

[gkkashyap]

Hello everyone!

I have successfully designed PIFA antenna for mobile phone size resulting an omni-directional pattern.But if i integrate the same in CAD tool with mobile phone casing,battery,PCB etc., the radiation pattern is no more omni.

Need help on how to reduce the effect?

Also,i have seen so many mobile phones have antennas stitched/attached to a special plastic piece inside mobile.How to design such antennas?

[bigSteve]

Why do you care if the pattern is omnidirecitonal? You should only worry about the efficiency.

For the printed antennas, they are often IFAs (INverted-F Antennas):
http://www.antenna-theory.com/antennas/aperture/ifa.php

[gkkashyap]

Thanks Mr.steve. That was informative.But for the mobile phones,the required radiation pattern is omni-directional,i believe so that mobile can pick signal from any direction?And yes,efficiency is also important parameter.

The IFA antennas,in the example of palm pre - How is the connection of the feed and shorting pin with the Mobile phone PCB?Is there an RF connector between this Yellow strip and PCB or any other contact pins,50 ohm microstrip trace contact etc?

Also,i believe this yellow strip was pasted onto the black plastic of mobile phone?How can this scenario be realize in antenna design CAD tool during the design stage?

[bigSteve]

Don't waste time making a phone antenna omnidirectional. The phone's size at 850 MHz is about a half-wavelength so the pattern will be roughly omnidirectional anyway (i.e. you couldn't make it with a high directivity if you wanted to). This criteria is a waste of time.

The connection on the palm pre is just a thin copper flex connection from the circuit board (with the radio, transmission line and impedance matching) up to the arms of hte IFA. This is not complicated.

For antenna design cad tools: I don't care.