Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [vna]

VNA (Vector Network Analyzer) - Device to measure characteristics of electrical networks

106 questions
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What is wrong with my 50 Ω grounded coplanar waveguide?

I've been working on a 4-layer design built around the EFR32BG13 Bluetooth Low Energy SoC. While trying to measure the impedance of the antenna to build a matching circuit, I discovered that my short grounded coplanar waveguide (GCPW) transmission…
Michael Cooper
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What makes open/short/load (OSL) calibrators so expensive/sophisticated?

An OSL that can go up to the GHZ can costs several hundreds if not thousands of dollars. What makes them so special? My theory is that a load involves some sort of special resistor and mantaining a 50ohm load into the GHz might not be so easy, same…
S.s.
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Is there anything particularly special about a "short" and an "open" in a VNA calibration kit?

I would like to calibrate a VNA with the reference plane at the end of a male BNC feedline. Surprisingly, female SOL kits are hard to find. There are many BNC 50-ohm loads available but I'm having trouble finding a BNC open and a BNC…
KJ7LNW
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Looking for criticisms for a VNA-like meter I am designing

I would like some help from anyone who could let me know any flaws or improvements in my design they can find and help me reconsider any last minute design fixes before I send my new project off to be mass produced. This is the second version of the…
Jeffrey Phillips Freeman
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1 answer

Where to connect the VNA during matching network tuning

I'm trying to design the matching network between an antenna and its transmitter, running at 868MHz, as shown below. There's probably about 20mm between the transmitter output and the Pi network. When connecting the VNA to the PCB in order to…
Amr Bekhit
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5
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2 answers

Procedure for experimentally determining decoupling capability?

I'm looking for a bullet-point list of a technique to experimentally determine a design's decoupling capability. I have a design that I'm working on that seems to be susceptible to ESD events in the field. I can't change the PCB layout - but I'm…
dext0rb
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4
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1 answer

Is my VNA broken or miscalibrated, or are these weird results normal?

My company got a new vector network analyzer recently and I'm using it to try to learn more about microwave circuits, especially the resonant cavities that we use in our measurement systems. I've seen some unexpected behavior in simple situations…
Adam Haun
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Vector Analyzer: what is IF bandwidth?

I noticed that if I set IF bandwidth low, the measures done with a vector analyzer are better (with higher SNR) but it is slower. Precisely, what does it happen when I change it? Can you explain me simply what it represents?
Kinka-Byo
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4
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2 answers

Why do long cables measured with a VNA show a "drop" in their attenuation curve?

I'm measuring the attenuation of several cables with a VNA (Keysight N5234A). When I measure the attenuation of long cables (10 m, 30 m, 40 m or 50 m) I realize that a "drop" appears at 500MHz (see the figure below). I have seen this "drop" in…
Gabriel
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4
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2 answers

How to measure antenna S21?

Please explain in detail how to take an S21 measurement for an antenna? I know what it is... but how do I physically connect the antenna to the VNA to take the measurement? Thank you in advance!
anduril16
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Tuning an antenna using a NanoVNA, Smith chart and impedance readings

I am new to antenna design and teaching myself how to optimize antennas using a VNA. I have created a monopole antenna on a PCB (i.e. a single length of track.) The antenna can be fed via a PI network and is connected to my NanoVNA via an SMA…
Daveo
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Match SMA antenna input connector to 50ohm

I'm using an "IOT" radio module designed with a 50 ohm single ended antenna output. The working frequency is about 868 MHz, the maximum transmit power is 14dBm. The module antenna output is connected to a 50 ohm PCB transmission line and some RF…
Theo
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How is the "open" component of the vector analyzer calibration kit made?

I've done some measures of S parameters with a VNA a long time ago. I'm not an expert om this, but I remember the procedure of calibration, which was using, for a single port, the three lumped elements open (infinite impedance,) short (0 impedance)…
Kinka-Byo
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1 answer

S parameters calculation from VNA file

I am trying to validate that our broadband LNA(Low noise amplifier) is working correctly. I wanted to measure the S21 of the LNA, I calibrated the VNA for the specified frequency range and measured performed a measurement. The file that I extracted…
Dimitar Zhekov
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How to connect the VNA to RF transmission line for antenna tuning?

I am working on a 2.45 GHz(Bluetooth) project. the design has a Chip antenna with 50 Ω impedance trace to connect antenna and chip. I intend to tune the antenna impedance using the Pi network using VNA. I have a basic VNA (I bought it on Amazon). I…
Sussy
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