Wire antenna problem

Hello all,
I decided to use λ/4 whipe antenna for my Tx/Rx at 100MHz, what's the input impedance of these antennas to consider while matching?
Thanks in advance,
Ahmad,

Quoted from:
http://www.electronics-tutorials.com...nna-basics.htm

Regards,
IanP

Hello IanP :)
Thanks for reply...
I have anothre question, how can i model the infinite ground plane,although the PCB diminsions is very small compared to antenna length?
Also, what are effects of increasing/decreasing the length more than λ/4?

Thanks alot in advance,
Ahmad,