what is the purpose of having a “thru cal” on RF PCB?












3












$begingroup$


I often find a thru cal on RF PCB like picture below.
What is the purpose of having this thru cal thing on the board?
One purpose I can think of is to test whether the designed transmission line is truly 50 ohms over the frequency of interest.
I did some research online and there are some people saying that the purpose of this thru cal is for "through-reflect-line" (TRL) testing. But I was not convinced with this argument since TRL technically needs other two lines (reflect and line).
Can anyone explain this to me from their experience?
enter image description here






pcb rf







share|improve this question









$endgroup$

















    3












    $begingroup$


    I often find a thru cal on RF PCB like picture below.
    What is the purpose of having this thru cal thing on the board?
    One purpose I can think of is to test whether the designed transmission line is truly 50 ohms over the frequency of interest.
    I did some research online and there are some people saying that the purpose of this thru cal is for "through-reflect-line" (TRL) testing. But I was not convinced with this argument since TRL technically needs other two lines (reflect and line).
    Can anyone explain this to me from their experience?
    enter image description here






    pcb rf







    share|improve this question









    $endgroup$















      3












      3








      3


      1



      $begingroup$


      I often find a thru cal on RF PCB like picture below.
      What is the purpose of having this thru cal thing on the board?
      One purpose I can think of is to test whether the designed transmission line is truly 50 ohms over the frequency of interest.
      I did some research online and there are some people saying that the purpose of this thru cal is for "through-reflect-line" (TRL) testing. But I was not convinced with this argument since TRL technically needs other two lines (reflect and line).
      Can anyone explain this to me from their experience?
      enter image description here






      pcb rf







      share|improve this question









      $endgroup$




      I often find a thru cal on RF PCB like picture below.
      What is the purpose of having this thru cal thing on the board?
      One purpose I can think of is to test whether the designed transmission line is truly 50 ohms over the frequency of interest.
      I did some research online and there are some people saying that the purpose of this thru cal is for "through-reflect-line" (TRL) testing. But I was not convinced with this argument since TRL technically needs other two lines (reflect and line).
      Can anyone explain this to me from their experience?
      enter image description here






      pcb rf




      pcb rf






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 2 hours ago









      Emm386Emm386

      283




      283






















          2 Answers
          2






          active

          oldest

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          3












          $begingroup$

          With the thru line you can do a simple response calibration.



          If you measure the response of the circuit including the chip, and compare it with the response of the thru line, you can get a good idea of what the performance of the chip itself is, without the effect of the connectors and transmission lines you used to connect to it.



          This kind of calibration isn't as accurate as a SOLT or TRL calibration, but it is better (if you want to know the response of the chip itself) than just assuming the connectors and transmission lines are perfect and lossless.






          share|improve this answer









          $endgroup$













          • $begingroup$
            that's what I kinda guessed! thanks for confirming this!
            $endgroup$
            – Emm386
            1 hour ago



















          0












          $begingroup$

          TRL calibration implies 3 tests ; Thru, open, short to normalize a setup for scattering parameters.



          If a test jig can simulate the effects on a circuit board Vgs control and another logic level then bidirectional switches can controlled to each of these 3 states.



          With these results, this or a duplicate board without this IC can be used to test a device under test (DUT) IC in the same user setup area to make A-B comparisons without unknown errors associated with an unknown test jig.



          Return Loss is a critical function of matched impedances but also the effects on gain or loss thru the channel.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
            $endgroup$
            – Emm386
            45 mins ago












          • $begingroup$
            i believe this board does what I described.
            $endgroup$
            – Sunnyskyguy EE75
            40 mins ago











          Your Answer





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          2 Answers
          2






          active

          oldest

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          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          3












          $begingroup$

          With the thru line you can do a simple response calibration.



          If you measure the response of the circuit including the chip, and compare it with the response of the thru line, you can get a good idea of what the performance of the chip itself is, without the effect of the connectors and transmission lines you used to connect to it.



          This kind of calibration isn't as accurate as a SOLT or TRL calibration, but it is better (if you want to know the response of the chip itself) than just assuming the connectors and transmission lines are perfect and lossless.






          share|improve this answer









          $endgroup$













          • $begingroup$
            that's what I kinda guessed! thanks for confirming this!
            $endgroup$
            – Emm386
            1 hour ago
















          3












          $begingroup$

          With the thru line you can do a simple response calibration.



          If you measure the response of the circuit including the chip, and compare it with the response of the thru line, you can get a good idea of what the performance of the chip itself is, without the effect of the connectors and transmission lines you used to connect to it.



          This kind of calibration isn't as accurate as a SOLT or TRL calibration, but it is better (if you want to know the response of the chip itself) than just assuming the connectors and transmission lines are perfect and lossless.






          share|improve this answer









          $endgroup$













          • $begingroup$
            that's what I kinda guessed! thanks for confirming this!
            $endgroup$
            – Emm386
            1 hour ago














          3












          3








          3





          $begingroup$

          With the thru line you can do a simple response calibration.



          If you measure the response of the circuit including the chip, and compare it with the response of the thru line, you can get a good idea of what the performance of the chip itself is, without the effect of the connectors and transmission lines you used to connect to it.



          This kind of calibration isn't as accurate as a SOLT or TRL calibration, but it is better (if you want to know the response of the chip itself) than just assuming the connectors and transmission lines are perfect and lossless.






          share|improve this answer









          $endgroup$



          With the thru line you can do a simple response calibration.



          If you measure the response of the circuit including the chip, and compare it with the response of the thru line, you can get a good idea of what the performance of the chip itself is, without the effect of the connectors and transmission lines you used to connect to it.



          This kind of calibration isn't as accurate as a SOLT or TRL calibration, but it is better (if you want to know the response of the chip itself) than just assuming the connectors and transmission lines are perfect and lossless.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          The PhotonThe Photon

          84k396195




          84k396195












          • $begingroup$
            that's what I kinda guessed! thanks for confirming this!
            $endgroup$
            – Emm386
            1 hour ago


















          • $begingroup$
            that's what I kinda guessed! thanks for confirming this!
            $endgroup$
            – Emm386
            1 hour ago
















          $begingroup$
          that's what I kinda guessed! thanks for confirming this!
          $endgroup$
          – Emm386
          1 hour ago




          $begingroup$
          that's what I kinda guessed! thanks for confirming this!
          $endgroup$
          – Emm386
          1 hour ago













          0












          $begingroup$

          TRL calibration implies 3 tests ; Thru, open, short to normalize a setup for scattering parameters.



          If a test jig can simulate the effects on a circuit board Vgs control and another logic level then bidirectional switches can controlled to each of these 3 states.



          With these results, this or a duplicate board without this IC can be used to test a device under test (DUT) IC in the same user setup area to make A-B comparisons without unknown errors associated with an unknown test jig.



          Return Loss is a critical function of matched impedances but also the effects on gain or loss thru the channel.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
            $endgroup$
            – Emm386
            45 mins ago












          • $begingroup$
            i believe this board does what I described.
            $endgroup$
            – Sunnyskyguy EE75
            40 mins ago
















          0












          $begingroup$

          TRL calibration implies 3 tests ; Thru, open, short to normalize a setup for scattering parameters.



          If a test jig can simulate the effects on a circuit board Vgs control and another logic level then bidirectional switches can controlled to each of these 3 states.



          With these results, this or a duplicate board without this IC can be used to test a device under test (DUT) IC in the same user setup area to make A-B comparisons without unknown errors associated with an unknown test jig.



          Return Loss is a critical function of matched impedances but also the effects on gain or loss thru the channel.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
            $endgroup$
            – Emm386
            45 mins ago












          • $begingroup$
            i believe this board does what I described.
            $endgroup$
            – Sunnyskyguy EE75
            40 mins ago














          0












          0








          0





          $begingroup$

          TRL calibration implies 3 tests ; Thru, open, short to normalize a setup for scattering parameters.



          If a test jig can simulate the effects on a circuit board Vgs control and another logic level then bidirectional switches can controlled to each of these 3 states.



          With these results, this or a duplicate board without this IC can be used to test a device under test (DUT) IC in the same user setup area to make A-B comparisons without unknown errors associated with an unknown test jig.



          Return Loss is a critical function of matched impedances but also the effects on gain or loss thru the channel.






          share|improve this answer









          $endgroup$



          TRL calibration implies 3 tests ; Thru, open, short to normalize a setup for scattering parameters.



          If a test jig can simulate the effects on a circuit board Vgs control and another logic level then bidirectional switches can controlled to each of these 3 states.



          With these results, this or a duplicate board without this IC can be used to test a device under test (DUT) IC in the same user setup area to make A-B comparisons without unknown errors associated with an unknown test jig.



          Return Loss is a critical function of matched impedances but also the effects on gain or loss thru the channel.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 51 mins ago









          Sunnyskyguy EE75Sunnyskyguy EE75

          64.1k22294




          64.1k22294












          • $begingroup$
            Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
            $endgroup$
            – Emm386
            45 mins ago












          • $begingroup$
            i believe this board does what I described.
            $endgroup$
            – Sunnyskyguy EE75
            40 mins ago


















          • $begingroup$
            Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
            $endgroup$
            – Emm386
            45 mins ago












          • $begingroup$
            i believe this board does what I described.
            $endgroup$
            – Sunnyskyguy EE75
            40 mins ago
















          $begingroup$
          Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
          $endgroup$
          – Emm386
          45 mins ago






          $begingroup$
          Thanks for your response! sorry but I don't understand some of your statement above. how can I insert a bidirectional switches on Thru cal? because I haven't seen any of RF evaluation board that is utilizing bidirectional switches. Most of RF eval board I've seen only has thru cal ...
          $endgroup$
          – Emm386
          45 mins ago














          $begingroup$
          i believe this board does what I described.
          $endgroup$
          – Sunnyskyguy EE75
          40 mins ago




          $begingroup$
          i believe this board does what I described.
          $endgroup$
          – Sunnyskyguy EE75
          40 mins ago


















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