A microstrip is a transmission line fabricated on a printed circuit board (PCB). They are much less expensive than a traditional waveguide although they typically have higher losses and less power handling capacity.

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Controlled Impedance Microstrip Frequency

Are you supposed to calculate the characteristic impedance for the frequency you are using or at 1GHz? I see pretty much everything calculated at 1GHz in all examples and papers. For example - for ...
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RF Circuit (what does capacitor do?)

I'm trying to work out why a 0.7pF capacitor was chosen. The circuit operates at 12GHz. At 12GHz, the capacitor has an impedance of about \$18\Omega\$. Also at 12GHz, ...
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Consensus on microstrip trace impedance calculations?

I'm designing a PCB that has a 2.4GHz signal that I'm routing to an SMA jack. I'm trying to figure out the geometry of the necessary microstrip trace. This is the first rf PCB I've worked on. The ...
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Minimal distortion in transmission line

In a transmission line, the condition for minimal distortion (caused by the line) are when (R/L = G/C) in the line, right? However, I don't see any reference to that in any application notes or ...
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How can I guarantee 50 ohm impedance on PCB trace?

I have a question. Imagine that I need to have a 50 ohms impedance in a PCB trace. For simple cases it's just applying the formula found all over the internet or use one of the online calculators ...
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279 views

Simulation software to terminate planar waveguides by geometry and material choice?

There are a lot of electromagnetics software modeling suites out there (HFSS, CST Microwave, Sonnet some I've heard of). I want to terminate a coplanar GS or GSG waveguide with 50 ohm. I know that ...
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Impedance calculators differ pretty much?

As you can see here to calculators I found show huge difference or didn't I set it up correctly? I didn't found hints on possible validity limits. Can someone say if one of those given out results ...
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869 views

How to terminate a coplanar waveguide with 50 ohm load?

So I want to structure a coplanar waveguide by lithography, VNA - coaxial - picoprobe - coplanar waveguide transition to measure impedance of the waveguide. As signal and ground lines are on one ...
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364 views

Huge variation of impedance calculators with same parameters?

There are many free (e.g. AppCad from Agilent) microstrip impedance calculators on the web. I've tested now several, because the first two did show a huge difference in the calculated impedance for a ...
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318 views

What is a good tolerance for impedance matching or how to calculate losses?

If you build a microstrip on a silcon wafer, connected by picoprobes via SMA connector and cables to a VNA, what is actually a good match of the impedances of the cables and the waveguide. Is there a ...
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72 views

Point of thin SiO2 layer for surface microstrip?

Reading some scientific journals I saw that research groups often use a silicon wafer with appropriate dielectric constant/relative permittivity and then build a microstrip (coplanar SGS or edge ...
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Matching RF traces

The datasheet for this part states the input and output are internally matched to 50 ohms. However what exactly does this mean? For example the output, would I still need a 50 ohm microstrip to ...
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Design a 1 GHz lowpass filter

I want to design a 1 GHz low-pass filter. I have tried to find a COTS lowpass filter at such high frequencies but I can't find one. Hence, I have decided to design one using microstrip lines. So, ...
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2k views

How to calculate signal propagation speed through vias?

There is a need to have a group of signals arrive simultaneously to their respective destinations, given that they start their journey at the same time. However, due to physical constraints it is not ...
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287 views

Microstrip over power plane

I am designing a 4-layer PCB with 16 channels of LVDS (differential signalling, 480MHz). My layer stackup is Signal-GND-Power-Signal. A microstrip design for the LVDS channels is usually traces over a ...