13.56MHz 10watt Power Amplifier

Hello so attached is my power amplifier that suppose to prove 10 watts into a dummy load using a frequency of 13.56MHz.

THE PROBLEM IS THAT IM ONLY GETTING 3 WATTS ON A WATT METER. Im driving 26.4dbm(little over 1/4 watt) into the base of my transistor. The transistor im using is the 2SC1969 BJT. Attached is the data sheet. I use a PI network to match 50 ohm to 5.6 ohm at the base. The PI NETWORK formula is as followed.
Q =√(��1/��2−1)
Xc1 = ��1/��
Xc2 = R2 √((��1/��2)/(��^2+1 −��1/��2))
XL = R1[(��+��2/����2)/(��^2+1)].

Then for 10watts of power a load resistance of 7.2 ohm is presented at the collector using the following formula.

Load Resistance = Vcc2/2*Pout


I then use a L-C-C network to match the 7.2 to the 50 ohm dummy load using the following formula.
XL = QRs
XC2 = RL√[Rs (Q2 + 1)/RL ? 1]
XC1 = Rs (Q2 + 1)/Q[QRL/(QRL ? XC2)]
L= XL/2πf ,C = 1/2πfXC.

Note:( i could of just used another PI network here)

The Q have have chosen for both networks is 3.

I cant seem to understand why im only getting 3 watts on the watt meter unless the watt meter isn't calibrated right cause i feel all my calculations and values are correct.

I think you will need more input power because the gain is not sufficient.

Sorry, your non-ascii characters do not show up properly (on my computer anyway). Recommend a different font. Or, if you go to Advanced Mode, you'll see Greek letters that may serve as stand-ins.

Would like 1 watt be sufficient?



I'm sorry about that should be

sqrt((R1/R2)-1)

I really did not compute but the answer is probably yes.



Right; computer languages are universally readable.

and I'm guessing you assuming this using the power gain equation and cause the data sheet says Gpe >= 12db

Sorry, it was shortsighted of me for not quoting all four lines where little squares appear where they should be characters. Guess we need your translation of the four lines below.



Interesting, I used the 'Reply with quote' this time. The non-ascii characters came out as diamonds containing little question marks.

I have attached two images that should clear this up. The L-C-C and PI network impedance matching

Whats C15 doing?, what is C12 doing?. Pi matching circuit is series L with a C down to earth at each end. Or series C with an L at each end going to earth.
In the .PDF for the transistor, the variable C in series with the L in the PI network is simply to tune (vary) the effective reactance of the series L.
Frank