How to decide power for local oscillator in mixer
Is there any criteria which will decide how much power required for oscillator
in mixer application.
L.O is of frequency 10GHz & 20 GHz.
please tell me how much minimum & maximum power is needed in downconversion(i.e to IF) application
First you need to decide upon the mixer topology, that will be the greatest determinant of how much drive you will need.
You will also need to consider the power levels you are mixing and what dynamic range requirements you have. That will affect the answer to the above.
There are a lot of system level questions you are going to have to consider before worrying about LO level.
If it is just for a college project question use a double balanced diode mixer and drive it with +10dBm.
Peter
hi
I am taking signal from 120 elements of antenna(patch)
so the local oscillator power required to be distributed for IF conversion is large.
as u sugested 10 dbm, is it sufficiet?
& its not college project!.
Hi Abhishekabs
When you are mixing a signal directly froma a patch-antenna I suggest that you need low conversion-loss in your mixer. Dynamic range and harmonic distortion would be in a second place, right?
What also has a high effect in LO power is the diode type (low-barrier, medium barrier or high barrier). The higher the diode barrier voltage the more LO power is needed. Take a look in the diode datasheet, normally they give the LO power range needed for this particular diode type.
If you use a medium or low-barrier diode at the given frequency in a double balanced mixer design, a LO power of 10dBm is surely a good starting value.
Regards
> am taking signal from 120 elements of antenna(patch)
>so the local oscillator power required to be distributed for IF conversion is large.
Does this mean that you are going to have a low noise amplifier and mixer asociated with each element in the array?
Local oscillator will be one feeding power to 120 elements
& LNA's are 120.
Patch antenna will be followed by LNA on same substrate.
Hi G4BCH,
i m using Gilbert Mixer topology, what should be the approx. driving power to mixer. i m assuming prf = -20dBm