All Questions
Tagged with impedance-matching impedance
139
questions
0
votes
2
answers
60
views
Why does my calculation for transmission line reflection and transmission at a load have infinite solutions?
Take a transmission line with some characteristic impedance and insert a load somewhere along the line. What are the transmitted and reflected signals, given an sinusoidal input. Physically this ...
- 343
2
votes
5
answers
439
views
Do audio impedance mismatches cause reflection (ie, 8-Ohm output to 20kOhm input) ? Does it matter?
I understand that audio source⇒input impedance mismatches are normal, and this answer provides a good reason as to why. However, having worked with RF more than audio, mismatches cause reflection that ...
- 2,190
4
votes
2
answers
1k
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Which is preferred over differential pairs: trombones or sawtooths?
I have been told that trombones are much better to use than sawtooths, even if sawtooths may be prefered in some certians scenarios.
Here I have added trombones to the differential pairs. If I had ...
- 1,324
1
vote
3
answers
86
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Is it possible to simulate reflections by designing an RLC transfer function?
Assume that you're knowing the PCB stack and the geometry of the conductor.
You're computing the capacitance per mm and inductance per mm and also the total resistance of the conductor.
That means you ...
- 1,324
0
votes
2
answers
78
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Difference between characteristic impedance vs complex impedance
Are there any differences between complex impedance of antenna pcb trace vs characteristic impedance of antenna pcb trace.
This question rised up because of online pcb trace impedance calculator doesn'...
- 11
1
vote
1
answer
47
views
Impedance of different track widths - Should I compute the average width?
Assume that you having one track that goes from 0.11mm in width to 0.09mm in width.
I want to compute the impedance, but I need to select the width. What option should I select?
The largest width of ...
- 1,324
0
votes
1
answer
80
views
Match 50 ohm impedance to LNA input impedance
I have following PCB version of circuit: on SMA input we have antenna strictly matched to 50 ohm, then we have regular RF switch IC, after RF switch impedance matching network and final stage is ...
- 65
1
vote
1
answer
182
views
Calculating output impedance of amplifier to match to 50 Ω
Below is a schematic of an amplifier. The inductor used is a 1 μH inductor, emitter resistor is 2.2 kΩ. The bias resistors are both 200 kΩ. The capacitors are both 1 μF. I am planning to design a ...
- 85
1
vote
2
answers
80
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Is the reason for guitar "tone suck", i.e. loss of high end frequencies with impedance mismatching, actually due to high reactance?
When connecting a guitar's output to an input with insufficiently high input impedance, the signal is undesirably filtered, which is referred to as "tone suck". To deal with this, it is ...
- 121
1
vote
1
answer
64
views
External circuit to increase the series capacitance of a resonant circuit
I am working with a long-range reader and antenna coil for a low frequency (135 kHz) RFID application (please see the basic representation below.) The reader features some unknown source impedance, as ...
- 21
1
vote
2
answers
256
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Half Bridge Impedance Matching
I’m currently building a half bridge induction heater and can’t understand impedance matching for the life of me.
Here’s an example of a basic half bridge induction heater. How and why was 45uH ...
- 405
0
votes
2
answers
102
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Antenna tuning and L/C matching
I see there are already a few questions asked wether it is better to physcally tune the antenna for said frequency and impedance or use a matching network. It seems the conscenus is often the physical ...
- 667
0
votes
1
answer
191
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How do you chain 2-port S-parameters onto a 1-port S-parameter?
With 2-port S-parameters, you can build up a circuit by chaining them together using ABCD or T-parameters, simply multiply the matrices:
We have measured a complex single port S-parameter of an ...
- 2,190
0
votes
1
answer
183
views
Impedance matching on VNA does not match calculation (with detail steps included)
I have a PCB with a pi-matching network, and I want to calculate the component values for the matching network.
I use LiteVNA and a WE-MCA Multilayer Chip Antenna for this project.
Here is the basic ...
- 1
1
vote
0
answers
43
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Impedance adaptation for two frequencies
I just received my first custom RF board that use 2.4 GHz and 5 GHz with a diplexer.
Unfortunately, it appears that the used PCB stack-up wasn't really what I expected so my traces are not 50 Ω, but ...
- 193