RF Detector Circuit Analysis

[Avinash Akotkar]

Here I am working on RF Detector, Here is my circuit and simulation results (input power with Output Voltage)
But Output voltage in uV, I am not sure if its correct one

Request to guide me on same, I have seen few papers , they were getting in mV

 

[vfone]

Actually to have a useful detector its output should be in volts.

https://www.jfwindustries.com/wp-content/uploads/2016/11/JFW-RF-Detector-Output-Voltage.jpg

 

[Avinash Akotkar]

Actually to have a useful detector its output should be in volts.

https://www.jfwindustries.com/wp-content/uploads/2016/11/JFW-RF-Detector-Output-Voltage.jpg

Thanks for update.
Do you have any paper or reference circuit which I can execute for same , this would be more helpful

 

[BradtheRad]

Looking at receiver listings, notice 'sensitivity' often is quoted as 1µV. You might get a few µV from a strong signal. Power level is small and hard to read on ordinary instruments. Your amplifier must not draw overmuch current from the antenna.

This means your amplifier should have very high input impedance.

Your amplifier must apply massive gain. Even so, the result might not be greater than 1mV (or 1,000 µV). And the result might look like noise anyway. RF broadcasts at every frequency come at us from all directions. Do you wish to pluck a particular station out of the mix?

Consider building an old-fashioned 'crystal' radio by which you can verify what you hear with what you see on measuring equipment. I hooked up my oscilloscope to a simple AM detector and was astounded to see local radio stations produce a carrier wave (say 830 kHz) bulging wider and narrower at audio frequencies as I listened.

 

[D.A.(Tony)Stewart]

RF spans at least 7 decades for broadcast.
Can you focus your question with purpose , Gain, BW, wide range, narrow , then what ?
Or is this an E-field (field strength) meter?

 

[BigBoss]

I cannot see any detector circuit here. There is just a differential amplifier and an output stage with a RC filter
RF Power detectors consist logarithmic amplifiers in cascade configuration and summing node.
It doesn't sense to me.

 

[Avinash Akotkar]

Looking at receiver listings, notice 'sensitivity' often is quoted as 1µV. You might get a few µV from a strong signal. Power level is small and hard to read on ordinary instruments. Your amplifier must not draw overmuch current from the antenna.

This means your amplifier should have very high input impedance.

Your amplifier must apply massive gain. Even so, the result might not be greater than 1mV (or 1,000 µV). And the result might look like noise anyway. RF broadcasts at every frequency come at us from all directions. Do you wish to pluck a particular station out of the mix?

Consider building an old-fashioned 'crystal' radio by which you can verify what you hear with what you see on measuring equipment. I hooked up my oscilloscope to a simple AM detector and was astounded to see local radio stations produce a carrier wave (say 830 kHz) bulging wider and narrower at audio frequencies as I listened.

thanks for giving more insights. Actually I am working Receiver chain. LNA+Mixer+IF+VGA, VGA gain will controlled by (RMS Peak Detector + Comparator). Below Diagram shows Feedback loop.

--- Updated Wednesday at 4:46 PM ---

RF spans at least 7 decades for broadcast.
Can you focus your question with purpose , Gain, BW, wide range, narrow , then what ?
Or is this an E-field (field strength) meter?

Thanks for response, I am working Receiver chain. LNA+Mixer+IF+VGA, VGA gain will controlled by (RMS Peak Detector + Comparator) .
A control voltage signal indicates whether the gain of the AGC should be adjusted higher or lower to maintain a constant output amplitude.

 

[D.A.(Tony)Stewart]

that does not answer my question on BW

 

[Avinash Akotkar]

I cannot see any detector circuit here. There is just a differential amplifier and an output stage with a RC filter
RF Power detectors consist logarithmic amplifiers in cascade configuration and summing node.
It doesn't sense to me.

Thanks for update. I am referring this IEEE paper for RMS power Detector. https://ieeexplore.ieee.org/document/4606329
Below circuit reparents same.

Please let me know, if I am doing something wrong

 

[Avinash Akotkar]

Hello Team,

I need your support here.
With same setup, I did transient analysis with 1mV as input amplitude and pd_output is 38mV output

Request to suggest me here if I am doing correct. And If its wrong then can anyone share IEEE paper for same for reference or any other link for same