impedance matching of power amplifier

How can we drive up the gain at high freq band? If the gain is monotone falling from 2110MHz to 2170MHz.

Due to gain-bandwidth product limitation for any amplifier it is usually easier to reduce gain in lower frequencies than increase it on high frequency end in order to get flat response. Different measures can be used: smaller series capacitor(s) at input and output circuits, adjusting biasing inductor(s), designing high-pass matching circuit etc. Designer must chose the best way in each individual case, there is no universal solution. First of all check the layout for parasitic components. Often it may help the most. After that you may tune the circuit components keeping in mind their SRF.

Best regards