seackone
Junior Member level 1
Hello,
I try to design my second PCB with Keysight Advanced Design System (the first PCB was just a 50 ohm microstrip) and Im looking for a how-to or something else. The plan is to measure three components in series. Now, im looking for an idea to calculate the microstrip transmission lines.
My first idea was to calculate the entire transmission line (with 50 ohm termination at the beginning and end of the stripline) and optimize the length and width of the elements with some goals (minimum reflection coefficient within 700 MHz and 2.5 GHz and special focus to 2 GHz).
The three shorted s2p containers are my elements of interest, the tee's are necessary in a later part of the design but not important at the moment. The results are shown in the next picture:
After that, i activated my s2p containers (all three elements are real inductors with an inductance of 13 nH) and simulated again.
I've got a capacity at 2 GHz, that's not what I want (I know, at high frequencies changes the inductance to a capacity, but there must be some design hints to avoid that problem). I expected an inductance about 40 nH as seen in the next picture (simulation with 3 inductors in series just optimal with wires between).
My question is: what is the usual way to design a stripline for that simple board? Should I optimize the stripline before every s2p container (second term element after the s2p container) with the goal of minimum transformation caused by the stripline? Or should I optimize all striplines at once (term at start and end of the stripline) with the goal to match my results with the expected reflecion coefficient in the third picture? Are there any design rules I have to observe?
The bottom layer of my PCB is a ground plane. On the top layer is just the transmission line without any ground. Is it necessary to add a ground plane on the top? Maybe for better results of my transmission line (i have no idea how to add a ground plane on the top)?
Thanks for your help!
I try to design my second PCB with Keysight Advanced Design System (the first PCB was just a 50 ohm microstrip) and Im looking for a how-to or something else. The plan is to measure three components in series. Now, im looking for an idea to calculate the microstrip transmission lines.
My first idea was to calculate the entire transmission line (with 50 ohm termination at the beginning and end of the stripline) and optimize the length and width of the elements with some goals (minimum reflection coefficient within 700 MHz and 2.5 GHz and special focus to 2 GHz).
The three shorted s2p containers are my elements of interest, the tee's are necessary in a later part of the design but not important at the moment. The results are shown in the next picture:
After that, i activated my s2p containers (all three elements are real inductors with an inductance of 13 nH) and simulated again.
I've got a capacity at 2 GHz, that's not what I want (I know, at high frequencies changes the inductance to a capacity, but there must be some design hints to avoid that problem). I expected an inductance about 40 nH as seen in the next picture (simulation with 3 inductors in series just optimal with wires between).
My question is: what is the usual way to design a stripline for that simple board? Should I optimize the stripline before every s2p container (second term element after the s2p container) with the goal of minimum transformation caused by the stripline? Or should I optimize all striplines at once (term at start and end of the stripline) with the goal to match my results with the expected reflecion coefficient in the third picture? Are there any design rules I have to observe?
The bottom layer of my PCB is a ground plane. On the top layer is just the transmission line without any ground. Is it necessary to add a ground plane on the top? Maybe for better results of my transmission line (i have no idea how to add a ground plane on the top)?
Thanks for your help!