berger.h
Member level 5
I have about 100W RF PA with MOSFET about class E, and I would like to understand how such a thing is proposed.
I looked into books like this or this
frankly, more I understand from this
Thing simpler and for beginnings i will ignore everything before G MOSFET see in picture.
Frequency of PA is 13,56MHz and all power (sin) go to 50Ohm load.
RF Choke L1?
If I understand correctly
L1 must form a resonant circuit with the capacitor in MOSFET Coos.
Her I have first problem.
IXFH12N50F have Coss 290pF , but this is for Vds 25V And I have more. How do I find a Coss for 50V?
In any case, L1 is 10 turn on any white coated ferrite OD 24mm and I measure 10uH on 100kHz
And this have resonant frequency about 3MHz?
What can't I see where the problem is?
Impednce Matching networks.
This convert low output impedance of MOSFET Zin to other Zou I thing 50Ohm.
I understand that, but I don't know how to calculate impedance of MOSFET amplifier?
Or if possible how I measure this impedance without expensive instruments like network analyzer?
That's enough for a start.
I looked into books like this or this
frankly, more I understand from this
Thing simpler and for beginnings i will ignore everything before G MOSFET see in picture.
Frequency of PA is 13,56MHz and all power (sin) go to 50Ohm load.
RF Choke L1?
If I understand correctly
L1 must form a resonant circuit with the capacitor in MOSFET Coos.
Her I have first problem.
IXFH12N50F have Coss 290pF , but this is for Vds 25V And I have more. How do I find a Coss for 50V?
In any case, L1 is 10 turn on any white coated ferrite OD 24mm and I measure 10uH on 100kHz
And this have resonant frequency about 3MHz?
What can't I see where the problem is?
Impednce Matching networks.
This convert low output impedance of MOSFET Zin to other Zou I thing 50Ohm.
I understand that, but I don't know how to calculate impedance of MOSFET amplifier?
Or if possible how I measure this impedance without expensive instruments like network analyzer?
That's enough for a start.