Questions tagged [vna]

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

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How to measure the input impedance of a laser diode/LED using a VNA?

It would be nice to have some advice on an issue I'm having with a laser diode. I have a DFB laser diode that has no kind of series resistor connected to it in the package. I want to make a driver for ...
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"Short" calibration

The following section from ST Micro's AN4974 - 'Antenna Matching' app note is a bit of a mystery. Is there a VNA / network analyzer guru out there who can tell me what the 4th line there is saying? I ...
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How to choose a sweep range for a known and unknown device with a VNA?

I'm trying to determine best practices for using a VNA to measure say, an antenna. Let's say I have a known antenna with a spec sheet that says it's frequency range is between x and y. Should I set ...
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How to measure radio wave penetration and reflection through different mediums

I would like to do a few experiments to test how different EM radiation frequencies (915 MHz to 5 GHz) interact with 3D print filament materials (like PLA, PolyCarbonate, TPU, etc...). Specifically I ...
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What is the frequency measurement range of a NanoVNA?

I have tried to measure a fabricated patch antenna which has theoretically multiband ranging from 1 GHz to 8 GHz, but when I tried to measure it through NanoVNA it barely shows the result from 1 GHz ...
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How to protect measurement equipment channels from ESD?

I was wondering what is the best way to protect measurement equipment, when handling like oscilloscopes/spectrum analyzers/Vnas/sensitive circuits (especially when stored in (none esd) foam)? I was ...
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How to improve measurement results with pocketVNA

I use a pocketVNA to measure the impedance of antennas and I also bought a couple of SMA connectors and a few cables to connect the antennas to the device. I run a 2-point calibration of the device (...
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Calibrating a VNA

I am using the Siglent SSA3032A-R spectrum analyser which has a Vector Network Analyser (VNA). Before measuring the impedance of an antenna under test so that I can match this antenna, I have to ...
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VNA Characterization of a non 75Ohm system

I'm trying to characterize a 75ohm cable using a VNA. As it differs from 50Ohm I need to do some adjustments with how I'm measuring but I'm not sure what is considered best practice for that. I was ...
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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 ...
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VNA Port Extension method

I have a PCB that has been handed to me that needs a match network setting between an SMA antenna and a Bluetooth module so operating freq = 2.4GHZ. I have a PICO 106 VNA and I have calibrated the ...
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1-port VNA quality factor measurement

I am using an Anritsu VNA (MS2034B) to obtain the LINEAR MAGNITUDE and PHASE of S11 via a calibrated 1-port measurement. The DUT is an inductively coupled RLC resonator (schematic below). However, I ...
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Mismatch uncertainty of S11 antenna measurement with adapter

A horn antenna needs to be measured for its S11 parameters, but it requires an adapter from a rectangular waveguide to a square waveguide. VNA calibration is performed at the end of the rectangular ...
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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 ...
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Spurious resonance in microstrip transmission line

We were trying to study the broadband response of a microstrip line on a 1.5mm thick Rogers AD1000 substrate whose Dk=10.7 and loss tangent=0.0023 at 10 GHz. The trace width is 1.2 mm. The S21 is ...
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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 ...
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Measuring and connecting a parallel LC circuit

I have built an LC circuit at 3.4 MHz and measured it's resonance with a VNA as schown in this picture and described here: The parallel LC circuit is connected to the output of the VNA and is open, ...
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What does an S21 of 0dB mean?

In a video titled PDN Measurements with a VNA Rolf Ostergaard shows how to transform the magnitude of the insertion loss S21 to an impedance value. This is the formula he uses: $$ Z = 25\Omega \times ...
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How to interpret VNA data?

I'm looking at the raw data from a VNA (HP 8720A) and I want to understand how to interpret it, and how to do after-the-fact calibration (ie: read raw data, then apply to it whatever corrections a ...
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How to VNA-calibrate a soldered coax with a 0201 50 ohm load at 2.4 GHz?

I need to tune a tiny ceramic antenna for Bluetooth Low Energy and I'm somewhat new to these high frequencies... I soldered a 0.81 mm diameter coax right before the Pi-network pads and want to ...
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Estimate transmitted ultrasonic power

I want to use ultrasonic (20 kHz to 100 kHz) transducers to couple ultrasound into pipes for cleaning purposes. You can easily buy those transducers with driving circuits on Aliexpress but I want to ...
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Is the VNA incident signal sine or cosine?

I wonder what kind of the input power signal is in the S11 parameter. Is the sine or cosine I know correct?
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What is the significance of a negative imaginary component in a S21 measurement?

What is the significance of a negative imaginary component in a S21 measurement ? For example, in the following plot of a passive network, the linear magnitude of the S21 parameter decreases with ...
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What is a good loop probe to use for non contact measurements at 13.56MHz?

I have a receiving antenna (9 turn spiral, 1cm in diameter) that I would like to measure (inductance) wirelessly at 13.56MHz. While looking through application notes from ST and NXP semiconductors, I ...
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Antenna matching circuit - weird behaviour

I have a 2.4GHz device with room for a Pi matching circuit. I cut J5 (to disconnect the MCU - brown line in layout picture), soldered the ground of the coaxial cable in the white region and the ...
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How to interpret the S21 phase measured by LCA or VNA?

I have measured the S21 phase of my device, which came as below. I would like to know if this phase is with reference to the input or with reference to the DC?
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How do I see the resonance of a high-impedance coil with a VNA?

When it comes to measurements with VNA, my experience tells me that whenever there is a "dip" in the S11 parameter, your takeaway should be that there is a resonance there (this is how the ...
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How to find Z impedance if I have only S11 (db) and phase

I need to measure Z line impedance. Using VNA I measured S11 it is -53.8785 dB and phase at this point is 175.6706. Could you explain using these numbers how to find R and jR S11 = (Zx-Z0)/(Zx+z0) = -...
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Correct calibration of reflection (S11) measurement

Following situation (apologies for my potential stupidity, I am very new to RF): I am doing a reflection/S11 measurement using a cut-off piece of coaxial cable (no stub, just a straight cut). The idea ...
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Why is S11 measurement changing on Agilent E5071B Network Analyzer?

Just a note: This is the second time I've ever used a VNA. I am trying to measure S11 of the 1.88GHz RF Input of this Powercast RF Energy Harvesting board. Link to the datasheet. Powercast Board ...
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Minimum Viable VNA N-to-N Test Cable for 2480MHZ

Can I get away with a $60 dollar N-to-N 1 meter cable from a reputable vendor for use in the scenario below? I have limited practical experience with a new VNA that just has an N connector output and ...
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OpAmp Buffer (S11 > 1)

I have the following buffer schematic set up: I am trying to understand why the S11 Parameter goes out of the unity gain circle, which indicates that the buffer schematic reflects more power than is ...
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VNA measurement of a domestic 3 wire AC cable used as a parallel transmission line

I am currently working on power line communication techniques for low and medium bandwidth applications. I was curious to calculate Z0 on a 3 wire, 1.5mm2 power cable. The theoretical impedance of a ...
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1 answer
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Chip antenna too good to be true?

I have the following setup: Very small PCB - 25mm in diameter that hosts chip antenna; I feed directly into antenna matching network with about 7.5cm coax via ufl connector; There are no other ...
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AVX M830120 SMD GPS antenna problems - cannot get GPS fix on a prototype board, strange S11 measurements

I’m struggling with AVX M830120 SMD GPS antenna in my project. I have used it in prototype board, did PCB layout more or less according to datasheet, and couldn’t get GPS fix no matter what I tried. I ...
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Vector Network Analyzers: Bode100 vs Keysight P5000A

I have been using Bode 100 machine earlier to measure Impedance and Phase of my piezoelectric transducer. The frequency range i work in is from 10kHz to 2.5MHz. I was just comparing this Bode100 with ...
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Circuit for selecting between PCB antenna and external

I'm just developing the second iteration of an 2.4Ghz sensor and receiver set. Because I can't afford the expensive development path of a big commercial project and because the environment these ...
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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 ...
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12 votes
1 answer
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What makes OSL (Open Short Load) 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 ...
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Coaxial cable test with VNA to estimate Wave Velocity and Attenuation

I'm doing a lab course concerning microwave measurements, during which I'm supposed to test an open, short and 50 Ohms terminated coaxial cable. The cable is connected to a VNA at the S_11 port and ...
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Measure antenna S11 next to another source

I have a dipole antenna designed to work on ~800MHz and 2.44GHz frequency, and a miniVNA Tiny USB device that I can use to measure return loss of the antenna. I connect the antenna directly to the DUT ...
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2 answers
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Meaning of S11 performing a clockwise arc circle about the smith chart origin?

I've tested a device with my VNA. It displays S11 in a Smith chart as a plot x(w) + iy(w) (w the frequency). Curiously, as w increases from 50KHz to 600MHz, the plot is an almost perfect 1/3 circle ...
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Calibrate for an inaccurate 50 ohm load in a DIY Vector Network Analyser (VNA) based on a VSWR RF bridge

I have built a "DIY VNA" using a frequency generator, an SDR receiver, a RF Reflection Bridge and a 50 ohm load. This is used to measure "VSWR values" of antennas to see what frequencies they are ...
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Soldered wire or test connector for VNA measurement?

I am designing a PCB for a IoT device, which will have an antenna inside a space-constrained plastic enclosure with metal screws. I know that I will have to tune the frequency response of the antenna ...
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2 answers
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One port Vector Network Analyzer (VNA) Calibration without the given standard Calibration Kit

I am trying to do a one port VNA calibration for measuring filters at the GHz band. The VNA that I am using is Keysight E5063A. However, I am running into some conceptual as well as some practical ...
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1 answer
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At which point and how to connect VNA on the PCB for antenna tuning?

I am working on a 2.45 GHz(Bluetooth) project. I have used a ceramic chip antenna with 50 Ω impedance for this board. I've placed a Pi network close to the antenna and also I have used an integrated ...
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Measurement of s11 with reduced power on NanoVNA

I am developing a 10.7 MHz IF amplifier for a radio receiver. In order to match the input to the output of the driving mixer stage (330 ohm) I need to measure the input impedance. I did the ...
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Low Pass Step and Low Pass Pulse sith Vextor Network Analyzer

I have an extremely basic question about time domain measurements with Vector Analyzer. It is something that is not explained in simple words in all datasheets/guides (maybe they think it is obvious ...
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Is there any device for measuring phase and gain of a device in frequency range as low as 0.1 Hz?

I need to measure phase and gain of a circuit starting from 0.1 Hz to 10 MHz. Most of VNAs are for frequencies of several MHz to GHz. I've just found one VNA for 1 Hz. Is there a device or method to ...
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Time Domain Measurements with Vector Analyzer

In my university I have done some time domain measurements with a VNA (by using the transform operation of the instrument). Precisely, I have selected the measurement of the real part of S11 while ...
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