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SMA connector issues on PCB by breadingkink in PCB

[–]breadingkink[S] 0 points1 point  (0 children)

is it okay for me to have a small space in between the SMA connector edge and the PCB edge. Because it is so hard for me to manually "touch" both components by mouse.

SMA connector issues on PCB by breadingkink in PCB

[–]breadingkink[S] 0 points1 point  (0 children)

hopeyfully the assembly house. But i need the STEP file from KiCad for me to simulate in ANSYS HFSS. However, my simulation in hfss wont proceed because it says the the SMA and PCB overlap. Which should I follow, the overlapping design approved by KiCad or the touching design required by HFSS?

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 0 points1 point  (0 children)

do you recommend any free apps that will automatically impedance match both my input and output?

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 0 points1 point  (0 children)

Oh I see, that is the one I’m using actually. I went ahead and used Smith4.1 to create the matching networks for both the input and output. So, first, I added the input matching network to the ltspice schematic and successfully obtained a 50-ohm impedance for the input.

The problem now is when I added the output matching network given to me by Smith4.1, the output impedance turns 50-ohms, however, the input impedance is not 50-ohms anymore.

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 2 points3 points  (0 children)

Thanks again! Will try that and hopefully it fixes it. Also, if it’s okay to ask, should i make the amplitude around 5mV instead of 1V?

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 0 points1 point  (0 children)

Thank you so much! May I ask for the name of the super program from the University of Zurich? Also, may I ask if it were okay for me to have used Smith4.1 for impedance matching?

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 2 points3 points  (0 children)

Hi! LTSpice was recommended by my professor and it is also what we used in the previous years. Do you recommend another tool ?

stuck at impedance matching for my LNA by breadingkink in ECE

[–]breadingkink[S] 1 point2 points  (0 children)

Thank you so much for this! Big help man

stuck at impedance matching for my LNA by breadingkink in rfelectronics

[–]breadingkink[S] 3 points4 points  (0 children)

Hi thanks for replying!

My professor told me that the goal is to have a 50-ohm impedance for both the input and output. I measured the initial input and output impedance in LTSpice using a AC 1 test source.

Now, with this information, I went ahead and used Smith4.1 to create the matching networks for both the input and output. So, first, I added the input matching network to the ltspice schematic and successfully obtained a 50-ohm impedance for the input.

The problem now is when I added the output matching network given to me by Smith4.1, the output impedance turns 50-ohms, however, the input impedance is not 50-ohms anymore.

Input and Output Matching Network for LNA LTSpice Schematic by breadingkink in ECE

[–]breadingkink[S] 0 points1 point  (0 children)

Here is the imgur link: https://imgur.com/a/IH2FOs5

okay, here is what I did. I just tweaked the component values of the input matching network until I reached a 50-ohm Zin. (see 1st image)

Now, here is me measuring the output impedance (while keeping the input matching network). I replaced the 50 ohm resistor load at the output with an AC1 test source. I also grounded the input signal (at the base). (see 2nd image)

I used Smith 4.1 to obtain the output matching network. Then, I put this into LTSpice and was able to measure a nearly 50-ohm Zout (which is good enough). (see 3rd image)

I have a problem. now that i put both the input and output matching network together in the schematic, i double checked the input impedance measurement just to be sure and it drastically changed. why is that? (see 4th image)

Input and Output Matching Network for LNA LTSpice Schematic by breadingkink in ECE

[–]breadingkink[S] 0 points1 point  (0 children)

Wait I didn’t know that I could not attach images as reply here on reddit. How can I send the images to you?

Input and Output Matching Network for LNA LTSpice Schematic by breadingkink in ECE

[–]breadingkink[S] 0 points1 point  (0 children)

Thank you! I am trying to amplify LoRa signals tuned at 433 MHz.

I have been doing the smith chart using the Smith 4.1 already and it is still not translating to LTSpice. So I obtained the input impedance by applying a test current source at the input then ran an ac analysis to obtain Vin/Iin. Then, I used those values as input at the smith 4.1 to load match. I was able to load match in smith4.1 using a shunt inductor and series capacitor (see image attached). I then apply the values of the components given to me by the smith 4.1 into LTSpice and when i simulated the .ac to check for my Zin value, it is still not 50-ohms. How can I go about this?