Summing of RF signals prior to antenna?

Hi all,

I'm relatively new to electronics and very new to RF design. The circuit I'm working on now has two VCOs, the second operating at roughly twice the frequency of the first. I need to transmit the output of both concurrently, after amplification. I've sourced an antenna that's suitable for both frequencies, but what's my best tactic for summing the two outputs? Is it a case of sourcing a high-power, very high-bandwidth op amp?

Thanks in advance.

Your solution is: Diplexer Filters
Diplexer Filters http://en.wikipedia.org/wiki/Diplexer
I think, the German Wiki has a better description: http://de.wikipedia.org/wiki/Diplexer
"A diplexer is usually thought of as a set of filters, again with a common feed point, that is used to combine or split signals travelling to or from an antenna, respectively, while providing isolation between the two independent paths."
RF / Microwave Filters, Diplexers & Duplexers: http://www.rfcafe.com/vendors/components/filters.htm
K.

You should explain your application in detail. The two VCOs can interact in very odd ways that may make your system fail, or make your government spectrum agency very unhappy.