10GHz high power amplifiers

10 GHz high power amplifiers
EME Conference Orebro 2015
Goran Popovic AD6IW
Available technologies
• TWT
• GaN transistors
• GaAs transistors
• Very efficient, bulky,
high voltage, x-ray
• High power density,
gain, very expensive
• Low voltage and
efficiency devices,
surplus available
GaN Transistors
• Triquint TGA2312 910GHz, 48dBm 13dB
38% eff.
• Cree CMPA601C025F
6-12GHz 46.2dBm 33dB
28V 33% eff.
Sumitomo elect. SGK10112A, 10dB, 33% eff.
Toshiba TGI0910-50. 31%
9dB
GaAs FET’s
• Fujitsu, Eudyna,
Sumitomo Electric
FLM0910, FLM1011
series, 3-25W 10V
• Toshiba TIM0910,
TIM1011 series
Surplus
• Alcatel
• Three stages x band
amplifier
• Fujitsu FLM1011
• 3W, 8W, 12W GaAs
Fet’s. In some units
15W final device
• Can be used as driver
for high power amp.
Amplifier line ups
7.5dB 8W
6dB 12W
7.5dB 15W
7.5 dB 3W
RF OUT
RF IN 23-25 dBm
Driver amplifier
7.5dB 8W
6dB 12W
7.5dB 15W
7dB 25W
RF IN
RF OUT
90 deg. 3dB splitter
3dB higher Power and
Linearity
90 deg. 3dB combiner
Balanced configuration
amplifier, two amp’s
RF IN
7.5dB 8W
6dB 12W
7.5dB 15W
7dB 25W
6dB higher Power and
Linearity
RF OUT
Driver amplifier design and
simulations
Final amplifiers
50W Balanced amplifier
• 2 x FLM0910_25F
• 8dB gain
• Idq 12.8A at 10V
GaAs fet’s bias circuits
200 Ohms @ -2.94V
300 Ohms @ -1.8V
Typically, Tc of Pot is 200300ppm Variation of gate
voltage is 100-150mV over
temperature change
500 Ohms
Common bias circuits
published in ham radio
magazines
330 Ohms
TIM0910-8
-5V from ICL7660
10mA with 0.5V output
drop !
DC
470 Ohms
Forward Gate current
32mA
Reverse Gate current
-4.1mA
Suggested Rg 100 Ohms
Rg
Issue
Low drive level the gate
current Igs is negative and
constant, but with high
level drive Igs is possitive
and can be large up to
hundreds of mA !
Rint.
DC
I>0
No forward current
Igs
Rp< =-Vpmax/2Igsmax
Rg
For FLM0910-25F
Rp=25Ohms
I>0
DC
Approx. Rp = 400 / Psat
Forward Gate current
64mA, Reverse Gate
current -11.2mA
Rp
Rp power dissipation (2x)
Rp=Vpmin.sqr/Rp
Rp diss = -0.5V sqr / 25
10mW use 1/4W res.
Rg
DC
DC
Rail to Rail Op amp
Totem pole configuration,
Very low output
impedance, drive
capacitive loads, and
provide GaAs FET with
forward and reverse Gate
currents
Control board schematics
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Four bias voltages
50mS sequencing
3W DC/DC converter
Isolated switch
T/R control
Implemenation and results
• 23dB gain
• 23dBm in 46.5dBm
45W Out
• PAE > 20%
• 13.5V 18A
• Unconditional stable
• Switching high side
mosfet Rds_on issue
Testing
Future developments
• Balanced amplifier with pair of
CMPA601C025 Cree GaN MMIC
• 25W each, 28V > 30dB Gain
• Multi ports power splitter-combiner
Wave guide Combiner
Questions ?
• Thank You
• Goran@ad6iw.com