ADL5243

I am using ADL5243 VGA,for amplification and I designed the circuit as mention in the datasheet,using the loop configuration at 2.63 GHz, and for e.g.,if we apply the input power -10dBm,2.6GHz signal from  RF generator,the output should be amplified,but we are getting  the output -35dBm.Where is the problem?I have designed the 4 layer PCB.