Questions tagged [vna]

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

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26 views

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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1answer
21 views

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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8 views

Coaxial Conducter Diameter for Antenna Tuning VNA Small Trace IoT

I have a very small IoT type board, and have been asked to tune the antenna on the system. The antennas traces are very small and I'm wondering what inner size conductor diameter folks are using on ...
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57 views

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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36 views

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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66 views

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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2answers
48 views

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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99 views

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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177 views

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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16 views

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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98 views

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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19 views

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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62 views

Can Network Analyzer measure Impedance, Conductance, Susceptance or is there a device that does all?

I want to measure the impedance, conductance and susceptance of a large metallic object (about the size of a boat), and I want to know if it is possible to measure using Network Analyzer. If yes, are ...
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102 views

Measurement of Resistor Parasitics Inductance and Capacitance

I have seen people doing some measurements of parasitic capacitance and inductance of some resistors, by using a vector analyzer and analyzing the graph of S11 with respect to frequency. To get this ...
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22 views

Measurement of Q and uncertainty

I am measuring the \$S_{21}\$ of some microwave cavity resonator. From the \$S_{21}\$ measurement, I try to extract the resonant frequency and the \$Q\$ of my resonator. To do that, I use a fitting ...
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25 views

Time Domain Analysis with Vector Network Analyzer

I have done some measurements with a VNA in time domain (by using the transform operation of the instrument). Precisely, I have selected the measurement of S11 (reflection coefficient at port 1 of the ...
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1answer
87 views

Interpretation of scattering parameter

Currently I am (non-engineer) trying to understand the origin of measured scattering parameters with a vector network analyzer and a 2 port system. The second port is terminated with a matched load to ...
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2answers
539 views

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 ...
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1answer
149 views

How do I find the return loss of a transformer from its 4-port S-parameter data?

I'm looking for information on the performance of Mini-Circuits T16-1-KK81+ transformer. The transformer is well-characterized, Mini-Circuits provided both insertion/return loss charts and raw S-...
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429 views

How to interpret s parameters including S21 on Smith chart on VNA display

I'm trying to become re-acquainted with S parameters, VNA, and transmission lines for some projects at work. I'm using Agilent, Advanced Design Simulator, to practice on the computer and to get the ...
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119 views

Impedance matching with complex impedance source

The method/steps to use a VNA to determine a matching network for a 50 Ohm (or whatever impedance) antenna seem mostly clear to me now. My current knowledge assumes though the transceiver (source) is ...
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1answer
80 views

How to measure VSWR of a single connector?

With a 2-port VNA, I would like to characterize the performance of a single coax connector, specifically to obtain VSWR. The specific situation is an SMA connector at the end of a short section of ...
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646 views

How to measure S11 of antenna using VNA for one port S-parameter measurement?

I have an antenna. I want to measure S-parameters of it using a network analyzer. I am not clear how to do it. Please explain. Thank you
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47 views

Contribution of solder parasitic to S parameter measurement

I have an antenna. I want to measure S-parameters of it using a network analyzer. The antenna has to be soldered to SMA cable for the measurement of S-parameters. After the calibration, will the ...
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65 views

Permittivity measurement using open-ended coaxial probe

I am trying to understand how the complex permittivity of liquids can be measured using an open-ended coaxial probe. For this kind of measurement, we put a open-ended coaxial line into the liquid ...
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2answers
111 views

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 ...
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203 views

Z=50 and Xs=0 but SWR is not 1.0:1

I measured an antenna with a VNA and differently to all other cases the SWR isn't low as expected. Here are some screenshot showing this: Similar situation, on the same antenna in the same ...
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1answer
232 views

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. ...
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172 views

S21 VNA Connector & Cable Loss?

I've tuned plenty of RF devices using my VNA for impedance matching. But I've never done an S21 measurement. I have a shielded tent with some connectors and SMA cables that are going to introduce ...
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1answer
520 views

Interpreting scattering parameters on a Smith chart.

I'm trying to become reacquainted with microwave circuits and how to analyze them, especially with a VNA. Just to get some practice I'm using Keysite ADS simulator. To get the feel of it I used the ...
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1answer
65 views

The meaning and role of the phase in antenna measurements with VNA

VNA measurements of an antenna return Z, RL, Xs, Rs... and also phase. I usually check Z=50 and Xs=0 to reach the max Return Loss and the lowest SWR 1.0:1, without having care of phase values. ...
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47 views

Are Cal Kit (SOLT) definitions unique by serial number?

I have an E5071B Network Analyzer and 85033E cal kit. One of the standards is broken now and needs to be replaced. This is the Male OPEN standard (Part number 85033-60018). Question: Will the ...
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34 views

How do the Ripple Limit lines get determined on antenna measurements?

I'm doing an S21 ripple measurement through a VNA and I understand how the measurement is done, but I don't understand how the limit is determined. I know you can specify the limit in dB and then you ...
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2answers
250 views

Connection to PCB from VNA

I currently intend to measure the Plane Capacitance of a PCB I'm going to build. I do have the measuring equipment (an VNA from R&S) but am unsure how to design the testpoints I am going to use (...
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480 views

Measure RF impedance of PCB or IC using a VNA Network Analyzer

I have a VNA and want to measure the impedance looking into my PCB. My VNA is pretty old, it's a 8753ES. My PCB includes a commercial Nordic or Dialog MCU with Bluetooth Low Energy (BLE). The path ...
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97 views

How can I design a double pole eight throw microwave (2-6 GHz) switch?

I need to design a DP8T microwave switch for a microwave imaging senior design project. The frequency range is 2 to 6 GHz. I need to switch between 8 antennas and a 2 port VNA. So each antenna ...
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439 views

Measure 4-port device with 2-port VNA

I need to measure a 4-port device (a directional coupler) using a 2-port VNA. This answer covers the basics, and this document goes into more detail. My problem is that I'm not sure how to perform ...
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1answer
58 views

Measuring PSR of a current reference chip

Some Background: I'm designing a test board to characterize noise and PSR of a multiple voltages(1V) and currents(1uA) reference IC. The chip has a single voltage source. I use ultra low noise MUX ...
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5k views

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 ...
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1answer
108 views

Current to Voltage Gain using Network Analyzer

Suppose I have an Voltage to Current Amplifier. And I'm characterizing it over a frequency range, can a Network Analyzer directly measure current to voltage gain (Iout/Vin)? (Or) do I have to use a ...
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189 views

S parameters measurement inside VNA

How does a Vector Network Analyzer (VNA) measure S parameters actually? Namely we have equations: \$b_1=S_{11}a_1+S_{12}a_2\$ \$b_2=S_{12}a_1+S_{22}a_2 \$ In theory, if i wanted to calculate ...
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53 views

VNA reflection and transmission of stripline stub

Testing this stub board. I understand S12 is attenuated at 1.79GHz due L=λ/4. So I calculate relative permitivity: εr = (c / 4Lf)2 = 3.3 But what does (εr) represent in a ...
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1answer
579 views

Methods for measuring cable path loss in RF Testing

I have been reading about various methods to perform a Cable Path Loss for RF Testing but not being a core RF person, I needed some insights on how it is done in Field or Lab. Here is my understanding ...
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3answers
459 views

VNAs and different characteristic impedances

What is the right technique to measure a matching network, cable, etc that is at a different characteristic impedance than 50Ω? In my case, I need to measure the SWR of a matching network that needs ...
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2answers
642 views

VNA calibration using cal kit vs PCB

So, its my understanding that the VNA (vector network analyzer) is designed to inject a known signal into an unknown device and analyze the reflected signal's amplitude and phase (both voltage and ...
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2answers
2k views

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!
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95 views

Measuring small capacitor parallel to big inductance (Network Analyser)

So what I have at hand is a cheap network analyser that can present the measured impedance in form of the values of different equivalent circuit topologies, e.g. R-L series or RL parallel. What I ...
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1answer
149 views

Designing a matching network with biasing inductor

I'm designing a 345MHz transmitter using the MAX 7044 ISM transmitter with an electrically small antenna and need to test the matching network. I will connect the VNA in place of the transmitter using ...
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1answer
302 views

What options do I have to measure directly impedance change (ohm) or deduce it indirectly from S-Parameters?

Basically I want to measure how impedance (Ohm) relative to Z0 (50 Ohm) waveguide is changing by varying a parameter. I currently measure the reflection coefficient S11 in a 1-port setup. Our VNA can ...
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1answer
642 views

Where to Measure S11 with a VNA

I have someone else's design that I have been asked to choose matching components for. The antenna is a chip antenna and the filter is a band pass SAW filter in a single package. The SAW filter is a ...