13.56MHz Signal Phase Shift by 90 Degrees

AI Thread Summary
A 13.56MHz signal requires a +90 degree phase shift for use in a power sensor with an AD8302 detector. The discussion emphasizes avoiding transistors due to their temperature-dependent β variations. Suggestions include using passive components like transformers, inductors, capacitors, and resistors to achieve the phase shift while maintaining a 50 Ohm impedance. An op-amp buffer is also proposed as a potential solution for impedance matching. Various passive network configurations, such as high-pass and low-pass T or Pi networks, are discussed for achieving the desired phase shift.
stickman!
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Homework Statement



I have a 13.56MHz signal to be used in a power sensor. However, in order for it to go through the RF/IF Phase and Gain Detector [AD8302], I need to shift the phase of this 13.56MHz signal by +90 degrees.

I want to avoid using Transistors, due to the variation in β of the component in higher temperature, and inconsistency overall.

Hope to hear from you guys soon.

-peace
stickman!
 
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Transistor amplifier stage gains do not have to rely on a particular value of β; they can be set by feedback in their bias networks.
 
Could you suggest me a way I could balance the 50 Ohm load and get a 90 degree phase change using transformer/inductor/capacitor/resistor?

-peace
stickman!
 
stickman! said:
Could you suggest me a way I could balance the 50 Ohm load and get a 90 degree phase change using transformer/inductor/capacitor/resistor?

-peace
stickman!

I think you'd have to have details about the load impedance and the source impedance to design something passive. When in doubt, an op-amp buffer is a possibility (high input impedance, very low output impedance).
 
gneill said:
I think you'd have to have details about the load impedance and the source impedance to design something passive. When in doubt, an op-amp buffer is a possibility (high input impedance, very low output impedance).

It'll be used in a Matching Box, so I want the Output Impedance and Input Impedance to be equal to 50Ω.

-peace
stickman!
 
I know you want a passive design but I will give you this as a blackbox device that should meet your requirement.

http://www.minicircuits.com/MCLStore/ModelInfoDisplay?13313152880980.24693377665622407

Adjust the control voltage to the needed shift.
 
Last edited by a moderator:
A passive network with 50 ohms in and 50 ohms out at 13.56 MHz which will give a 90 deg. phase shift can be any of the following. In every instance the two outer elements are the same, capacitors or inductors, and the inner one is the opposite. -Xc = Xl = 50 ohms. For 13.56 MHz, L = 590 nH, C = 233 pF.

High pass T network
Low pass T network
High pass Pi network
Low pass Pi network
 
nsaspook said:
I know you want a passive design but I will give you this as a blackbox device that should meet your requirement.

http://www.minicircuits.com/MCLStore/ModelInfoDisplay?13313152880980.24693377665622407

Adjust the control voltage to the needed shift.

That link isn't working for me, and I wasn't able to find a MiniCircuits phase shifter that works in the range of 13MHz. Do they have one?
 
Last edited by a moderator:
They do. check this - http://www.minicircuits.com/pdfs/SPH-16+.pdf

You could also use a RC phase shifter -
you have 2 signals, one with 0 phase shift and other with 180 phase shift. Feed the 0 phase shift to R and 180 phase shift to C. Vary the R, you can get phase shift from 0 to 180.
 
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