testing 1 WATT transmitter

for 1watt , 1.3GHZ transmitter ,
last stage RF amplifiers then SMA then antenna...
if the antenna is not connected , can i power up the circuit to test otherstages ?

imean if the antenna is not connected will the sma connectors reflects the power back to the circuit when i power up the circuit (no antenna)?

Yes - if you power up the transmitter without the antenna, there is a possibility you will damage the RF output power amplifier.

In general, when testing a transmitter, you should load the PA with the proper impedance load. You can use a dummy load consisting of a resistor of value equal to the antenna impedance - just use one with a power rating high enough to keep it from destroying itself with heat.

There are passive resistive circuits built into cylinders with SMA (and other type) connectors. Some are 50 ohm terminations. Attenuators can also be used for a load. The return loss is twice the attenuation.

http://www.minicircuits.com/dg03-154A.pdf is an example of some low cost 2W attenuators.