I have a 2.4 Ghz transceiver circuit that is used in a mobile wireless
application. The application runs from a watch battery so power is
crucial. The device will only need to transmit up to 4 or 5 meters to
its receiver. I need to know what kind of antenna to use. I read that a
dipole is typical. My question a

1 - what is the minimum length that this antenna can be?
2 - what is the minimum diameter that the antenna can be?
3 - can the antenna be etched on one side of a PCB (to avoid attaching
a physical cable)?
4 - does the length / diameter of the antenna affect the power output?
5 - any manufacturers you know of that sell very small antennas for
this application?

What I need is the smallest antenna possible!

Thank you for your insight.
Johann Blake