Questions tagged [impedance-matching]
Impedance matching is a process of making one impedance equal to another another.
730
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
1
answer
32
views
Unusual chip antenna feed impedance matching
I'm designing a PCB with a RFANT3216120A1T ceramic SMD chip Bluetooth antenna.
The part is somewhat poorly documented and does not state the antenna impedance. The datasheet shows a test board with an ...
- 888
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
1
vote
1
answer
57
views
Maximizing magnitude of fields created by an antenna
I have a small loop antenna (\$C\$ = circumference<< \$\lambda\$ ). I am interested in the fields created by this loop at a distance \$D\$ along the z axis also small compared to \$\lambda\$.
I ...
- 395
0
votes
0
answers
44
views
Impedance matching T/R switch
I do drive a piezo as transceiver. My transmitter provides square burst around 10Vpp which is too big for simply switching through a diode by dc biasing. I found out that bridge rectifier structure ...
- 39
4
votes
2
answers
524
views
USB Data communication issue on a panelized pcba hardware test platform
I need some help..
I developed a test platform for the hardware tests of an electronic board panelized in sets of 10. The boards are placed on the test platform in their panelized form. As shown in ...
- 195
0
votes
0
answers
38
views
Antenna complex input impedance into real impedance
I'm trying to design a loop antenna and make it resonate around 100 MHz.
Using a standard 50 ohms port, the resonating frequency is not at 100 MHz. Since I cannot change the geometry, I'm going to ...
- 103
0
votes
1
answer
48
views
S-parameters of a matching network
I have the following matching network designed for \$\omega=2\pi\cdot 1GHz\$ and I want to calculate \$S_{11}\$ and \$S_{21}\$. The normal definitions/calculation setup for S11 that I use are in the ...
- 675
2
votes
1
answer
50
views
Single stub matching of loop antenna at 4.2 GHz
I am trying to match a loop antenna using the single stub matching technique.
Operation frequency: 4.2 GHz
Vacuum wavelength: 7.2 cm
Cable:
Impedance: 50 Ω
Velocity factor: 0.66
The antenna impedance ...
- 395
0
votes
0
answers
46
views
S21 calculation
In this post
It mentioned that there's a factor 2 in S21 value.
But I'm still don't understand why there's a 2 in it.
My schematic is shown below.
Shouldn't S21 = Vout/Vgen?
My question is: where is ...
- 141
0
votes
1
answer
63
views
Understanding impedance matching in RF PCB applications (STM32WB55)
I'm just getting into RF design since I inherited a board that uses an STM32WB55C for BLE. For now I want to start getting more familiar with the RF concepts since I don't have a lot of experience.
As ...
- 871
0
votes
1
answer
32
views
Correct connection of a Wi-Fi board having both printed antennas and U.FL sockets
An RF part of a dual antenna Wi-Fi module from Aliexpress.
We can see coax sockets connected in parallel to printed antennas. Two external antennas and corresponding pigtails are part of the package.
...
- 13
4
votes
2
answers
1k
views
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
views
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
views
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