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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Phase Velocity in PCB Edge Coupled Microstrip

I would like to calculate the phase velocity (\$v_p\$) in an edge coupled (differential) microstrip such as the below. It's possible to calculate \$v_p\$ for an embedded microstrip with the ...
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65 views

Termination resistors usage

My doubt pertains to the usage of termination resistors. This is a continuation of the discussion I saw in this link - Termination resistor. I understand that any transmission line can be simulated ...
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Inductance calc for Edge Coupled Differential Pair?

Apologies up front if this topic has been addressed. I've searched on StackExchange and am concluding that this structure is uncommon as there is no ground return accompanying the differential pair ...
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152 views

How to route a trace on PCB with 50 Ohm impedance?

I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. I use FR-4, so H=1.5mm, T=0.035mm and Er = 4.5. 2-side PCB, one side with signals, the other with GND. I set ...
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Microstrip through passive components

I am a bit confused with the implementation of a microstrip line to an u.FL connector. In order to maintain a 50Ohm line, the trace width would need to be ~0.1 inches wide, I have a pi matching ...
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106 views

Embedded microstrip antenna

How well known are embedded microstrip antennas in general and are they feasible. I want to pot a 2.4 Ghz antenna for product reliability/water and shock proof reasons, but finding information and ...
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Frequency dependent impedance calculation for microstrip

I need a hint. I'm stuck on outer layer impedance calculation for high speed design. Other PCB designers route high speed tracks on inner layers because of not controlled plating thickness on outer ...
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158 views

PCB microstrip antenna

I have a query regarding PCB microstrip antennas. Most of my antennas have been straightforward with the U.fl being placed close to the RF feed point. Maybe a PI filter is added. But I have seen many ...
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Antenna (microstrip) tuning

I have designed a 2.4GHz wifi antenna. It is a microstrip antenna which is not too close to the source. I understand that if the antenna (U.fl) is very close to the wifi source then there is no need ...
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84 views

ANT-MMCX and Microstripe line and UHF RFID module circuit designing

Below, you see the only schematic of a 6 pages-datasheet of an UHF RFID module (working frequency = 840...930 MHz): There are three questions: What is that ANT-MMCX? I search it in Google and I ...
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63 views

Microstrip lenght problem

I'm simulating a single microstrip half-wave resonator (1.8 GHz) in Sonnet and using ADS LineCalc tool for calculating the microstrip length but I'm getting a wrong number. Substrate parameters ...
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Can differential USB traces be routed relative to Power (not Ground) planes?

I would like to route my USB 2.0 (12MHz) signal on the bottom layer of a 4-layer PCB. However, the edge-coupled microstrips would then be referenced to the power plane, not the ground plane. The ...
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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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212 views

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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430 views

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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538 views

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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600 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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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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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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661 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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84 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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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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425 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 ...