13.56MHz Signal Phase Shift by 90 Degrees

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Discussion Overview

The discussion revolves around the challenge of achieving a 90-degree phase shift for a 13.56MHz signal intended for use in a power sensor, specifically addressing methods to accomplish this without using transistors due to concerns about temperature variation and inconsistency.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses the need for a 90-degree phase shift for a 13.56MHz signal and seeks alternatives to transistors.
  • Another participant suggests that transistor amplifier stage gains can be set by feedback in their bias networks, implying that reliance on β may not be necessary.
  • A participant requests suggestions for balancing a 50 Ohm load while achieving the desired phase shift using passive components like transformers, inductors, capacitors, or resistors.
  • It is noted that details about load and source impedance are crucial for designing a passive solution, and an op-amp buffer is proposed as a potential alternative.
  • A suggestion is made to consider a blackbox device that could meet the phase shift requirement, along with a link to a specific product.
  • Another participant lists various passive network configurations that could achieve a 90-degree phase shift, providing specific values for inductance and capacitance at 13.56 MHz.
  • Concerns are raised about the functionality of the provided link to a phase shifter, with a request for confirmation of availability for the 13MHz range.
  • A participant confirms the existence of a suitable MiniCircuits phase shifter and introduces the concept of using an RC phase shifter to achieve variable phase shifts.

Areas of Agreement / Disagreement

Participants present multiple competing views on how to achieve the desired phase shift, with no consensus reached on a single approach or solution.

Contextual Notes

Participants mention the importance of load and source impedance details for passive designs, indicating that assumptions about these parameters may affect the proposed solutions.

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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