Guest
Hi,
I am running a pss simulation on a few transistors which should act as
a PA.
Ive defined 2 ports at the input and output.
Pin is the power out defined in port 1 under Amplitude (dBm), and the
input wave is a sine at 1 frequency. there are no other tones defined
in the port or anywhere else.
The pss simulation is defined as 1 pss 2.4G 3 -40 0 Large Port1
I am sweeping the input power(Pin) out of port 1 over a some range so,
when i plot the power out of port 1 vs the swept variable it should be
a straight line with a slope of 1.
BUT...
The output power of port 1 is at least 5 dBm higher than the input
power and it has spectral components. I assumed that it might be
modeling spectral regrowth which takes care of the spectral components
but not the higher power.
Also the output power changes if i choose terminal or port (fixed
(R)). The higher output occurs if i choose port (fixed (R)) but i get
a lower output if I choose terminal. but this only occurs at the input
port, the output ports power is the same if i choose either of the 2
above.
If i change the simulation variable to lets say the width of some
transistor and fix the input power Pin to be constant. Then if I plot
the power out of port 1 vs the width it changes again as a function of
the width when it should be constant. I am really confused on how the
power out of the port is defined and how it can change.
so when i plot the 1dB compression point i am wondering if the input
power is 5dBm higher or is it Pin.
Secondly is the input power 1/2 VxI* like it is at the output or does
it assume equal impedances for the source and the input so something
like Pav= V^2/(4*Rport)? I ask this because ideally i would like to
provide pulse input and i need to be able to accurately measure the
power out of the port.
An Aside,
I am using a MOS transistors and the S11 of the device seems
outrageous for my device size (pretty large, W/L = 320 and a few
fingers).
gamma is about 0.95 at about and the angle is -30 approximately but i
dont think that Cgs is that small at 2.4GHz.
Has anyone else seen results like this?
Any help with this will be greatly appreciated
Thanks
Travis
I am running a pss simulation on a few transistors which should act as
a PA.
Ive defined 2 ports at the input and output.
Pin is the power out defined in port 1 under Amplitude (dBm), and the
input wave is a sine at 1 frequency. there are no other tones defined
in the port or anywhere else.
The pss simulation is defined as 1 pss 2.4G 3 -40 0 Large Port1
I am sweeping the input power(Pin) out of port 1 over a some range so,
when i plot the power out of port 1 vs the swept variable it should be
a straight line with a slope of 1.
BUT...
The output power of port 1 is at least 5 dBm higher than the input
power and it has spectral components. I assumed that it might be
modeling spectral regrowth which takes care of the spectral components
but not the higher power.
Also the output power changes if i choose terminal or port (fixed
(R)). The higher output occurs if i choose port (fixed (R)) but i get
a lower output if I choose terminal. but this only occurs at the input
port, the output ports power is the same if i choose either of the 2
above.
If i change the simulation variable to lets say the width of some
transistor and fix the input power Pin to be constant. Then if I plot
the power out of port 1 vs the width it changes again as a function of
the width when it should be constant. I am really confused on how the
power out of the port is defined and how it can change.
so when i plot the 1dB compression point i am wondering if the input
power is 5dBm higher or is it Pin.
Secondly is the input power 1/2 VxI* like it is at the output or does
it assume equal impedances for the source and the input so something
like Pav= V^2/(4*Rport)? I ask this because ideally i would like to
provide pulse input and i need to be able to accurately measure the
power out of the port.
An Aside,
I am using a MOS transistors and the S11 of the device seems
outrageous for my device size (pretty large, W/L = 320 and a few
fingers).
gamma is about 0.95 at about and the angle is -30 approximately but i
dont think that Cgs is that small at 2.4GHz.
Has anyone else seen results like this?
Any help with this will be greatly appreciated
Thanks
Travis