Questions tagged [s-parameters]

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53 views

Two-port network parameter measurement using an LCR meter

I was wondering if it's possible to find the admittance parameters of a pi two-port network experimentally using an LCR meter. For the network shown below, we have $$ \begin{bmatrix} I1\\ I2 \end{...
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2answers
43 views

Recommended Fixture for a 10 MHz to 40 GHz S-Parameter Collection

I would like to characterize a range of SMD and TH components in order to show how different components have different parasitic elements that must be accounted for as frequency increases. I would ...
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0answers
35 views

Scattering parameters of a 2-port system

So I have been trying to brush up on transmission lines and have come across a question which has me stuck. The question is: Find the scattering parameters of a parallel impedance \$Z_p = 100 - j50\ ...
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26 views

Deriving S-Parameters for Hybrid 90° Coupler with Isolated and Delayed P Shorted from 90° Hybrid Coupler S-Param Matrix

I'm trying to derive the s-parameters for a 90 degree hybrid coupler using the s-parameter matrix that is known for a coupler of this type when the ports are configured correctly. In this situation, I'...
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2answers
105 views

How to compute S21 when port 1 and port 2 reference impedance (Zo) are different

The attenuator given in the figure is a 6 dB attenuator when both port 1 and 2 have a reference impedance of 50 Ω. Then, their S-parameter matrix (when port 1 and 2 have 50 Ω reference impedance) ...
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1answer
51 views

Passivity and Causality of PCB channel

We use S parameters to analyze a PCB channel. Once the S parameters are extracted, what I have seen is SI engineers will check the S parameters obtained are passive and casual. I have some questions ...
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36 views

Combining S-parametric Blocks

I would like to ask you, please, how I can combine general S-parametric blocks together. Consider the situation in the following picture. Considering this example, I would like to connect these three ...
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1answer
51 views

Calculating the real power consumed in a two-port network using its S-parameters

I would like to express the real power consumed in a two-port network using its S-parameters. Assume for simplicity \$\underline{Z}=R\in\Re\$ (1) My idea was using energy conservation: $$ P_{in} = P_{...
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23 views

RLGC extraction from the Asymmetric S-paramter

In the signal integrity of high speed interconnect, in case of extraction of RLGC from S-parameter of it, they assume the S-parameter is symmetric and reciprocal. but in practical case S-parameter of ...
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2answers
97 views

Why do we use S parameters for channel modelling, rather then using Z, Y, h or any other parameter?

For channel modelling in high speed PCBs we always use S parameters. What is the specialty of S parameters for this purpose? Why we are not using Z, Y, h or any other parameter? How do we determine ...
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1answer
21 views

Can port parameters in one representation (mag-angle, decibel-angle, or real-imaginary) be converted to the other?

I'm trying to figure out what network parameter data would be "best" to use when generating a Touchstone file, or if the different data representations are equivalent in terms of the ...
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1answer
107 views

S Parameters Channel Modelling Time domain representation of insertion loss

Below is the insertion loss waveform obtained after S parameter of a channel.The waveform is in frequency domain. May I know what is the equivalent time domain waveform and how to obtain it from this ...
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1answer
112 views

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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0answers
56 views

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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0answers
42 views

De-embedding ceramic filters

I want to design a diplexer using two ceramic filters. S2P files of the filters are not provided. Therefore, I designed a PCB which can be shown below to obtain their S2P parameters. In the first ...
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85 views

S21 derivation on this schematic

I saw this equivalent model for a switch device on a book. The resulting S21 equation is shown below. It seems not too complicated, but I cannot derive this equation. Could somebody enlighten me and ...
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0answers
24 views

Create spice model from S parameters file 2 terminals

I want to do a simple design using this amplifier. Though it is simple, I would like to somehow simulate it to fine tune some components. The manufacturer provides a ".S2P" (here) file with ...
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29 views

The accumulative error on the crosstalk items (s23, s14) when cascading multiple 4-port s-parameter

I found there seems existing the accumulative errors on the xtalk items when doing large number of s4p cascading. Here is a brief summary: When it is two port network, ie, s2p, things are much better,...
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46 views

How do I determine the S-matrix for a combined series and shunt capacitors circuit?

I need to compute the S-parameters for the following two-port circuit, with combined series and shunt capacitors. simulate this circuit – Schematic created using CircuitLab I have tried ...
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1answer
42 views

Differential Pair Mode Conversion [closed]

What is the purpose of using these mode conversions? SCD Input: Differential Output: Common SDC Input: Common Output: Differential
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1answer
27 views

Are multiple reflections accounted for in S-parameters?

When the S-parameters of a 2-port device whose input and output impedance are different from 50 Ohm are calculated/measured in a 50-Ohm system, multiple reflections occur at port 1 and port 2. Let's ...
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2answers
503 views

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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0answers
22 views

Confusion regarding connecting nport in cadence while trying to find input impedance

I am a little bit confused on how to to connect the nport in the case where I try to find looking in impedance of a transmission line which is loaded by a 1pF capacitor on the one side. As shown in ...
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3answers
216 views

Bad Reflection from SMA Board Connector at 4-8 GHz

recently I have tried to design a simple SMA-to-microstrip connector PCB intended for 4-8 GHz. The connectors used are vertical with surface-mounted centerpin (link). The design idea was to simulate ...
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0answers
77 views

Causes for negative port resistance of passive device (or obtaining |S11|>0 from measurements)

Suppose you have two reciprocal (passive) devices, A and B, both described with S-parameters \$S_a\$ and \$S_b\$. With a VNA, you measure \$S_a\$ and \$S_{\rm tot}\$ (S-parameters of AB, both devices ...
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3answers
492 views

Deriving the S-parameters, different Matched Loads possible?

I guess this is more of a conceptual question but for the problem below Im having trouble getting started on how to derive the S parameters for the network. I noticed that the network at 28.025 GHz ...
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2answers
247 views

How is Wilkinson power divider lossy?

In an ideal Wilkinson power divider(because in practical there will always be resistive loss), the scattering parameters, or S matrix is given as: From the condition that checks if network is loss-...
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2answers
150 views

Why 20 is multiplied for the SdB=20 Log (Smag)?

Why factor of 20 is multiplied while converting the ratio of two powers/voltages to dB value? SdB=20 Log (Smag) where: SdB = value of the magnitude, in dB Smag = value of the magnitude, as a number
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0answers
107 views

S21 phase vs phase shift measure

Hi am simulating in ADS microstrip T-lines for a 3 bit phase shifter, the lines are calculated to insert 55,110 and 220 phase shift for 2.16Ghz. With the S-Parameter simulation i can see the phase of ...
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1answer
79 views

What is a "loading capacitor for pin parameter measurement?"

I am designing my first PCB with an MCU and I see this section in the datasheet that brings up a loading capacitor used for pin parameter measurement. I don't believe this is load capacitance for a ...
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1answer
54 views

S-parameters vs device model

Many vendors provide both S-parameters and simulation models for their devices. Having encountered device models that when simulated, don't result in exactly the same S-parameters as the touchstone ...
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1answer
52 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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2answers
430 views

What's the S parameter in an Antenna

So, I'm struggling to understand what the S-parameter is in real-life terms; I mean, what does the S-parameter tell us about an antenna? I have designed a microstrip Wi-Fi antenna that should work at ...
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1answer
75 views

3-phase inductance calculation homework

This is a homework question where i am stuck. Please help me out in this: Three similar impedances are connected in star across 2000 V, 50 Hz three phase supply. Power absorbed is 300 kW. ...
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2answers
62 views

What is the theory behind these current equations? (for Z paramaters)

In the photo below is shown the method for deriving z-parameters of the circuit. Apologies for my badly drawn values for resistors as they weren't shown in the original image. Basically I'm struggling ...
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1answer
107 views

Can these S-parameters be derived?

I have been trying to derive the S-parameters of a lossless T-junction of transmission lines. Here's a diagram from Google: This is an exercise in microwave network analysis, not in design, so the ...
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1answer
337 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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1answer
99 views

Can I get the S21 parameter from a one-port open, short and load reading?

I am currently working with a custom rectangular waveguide, which has one port abled to connect to a VNA,(call it port a) but the other side cannot, (its part of a bigger system but for now its only ...
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1answer
51 views

Can a Unilateral Amplifier be Unstable?

When designing microwave amplifiers, stability is an important factor to consider. Stability is usually measured with the K factor. In a unilateral network, S_12 = 0, and this makes the K factor ...
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0answers
30 views

Can I determine 2-port s-parameters from 1-port measurements?

I have a 1-port impedance bridge. Can I get the four s-parameters of a 2-port device by measuring each "sending" port with the "receiving" port terminated in Z0 and reversing the measurement to get ...
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1answer
115 views

Coupling coefficient of microstrip resonators

I am working in HFSS and I'm trying to determine the coupling coefficient between two microstrip resonators (k) so that I can design a filter using a certain resonator shape. I have the formula I need....
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1answer
74 views

Scattering Matrix with Power Waves and Voltage Waves

I read that for a given N-port network there are two different conventions about defining the incident and reflected waves. This is the first convention: This is the second convention (we see that ...
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2answers
367 views

How to model a one-port (reflection) measurement in SPICE?

I have the equivalent circuit for an antenna and I would like to use SPICE to simulate the \$S_{11}\$ (reflection coefficient) response. I know how to simulate two-port measurements (like shown here),...
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1answer
372 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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1answer
178 views

Question on Matched 3dB attenuator

For the second picture below, how to derive the expression for Vo ? I suppose there is some in-betwen maths that I missed out. Note: 41.44 ohm is the parallel equivalent for (50 ohm + 8.56 ohm) || ...
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1answer
1k 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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376 views

Z parameters to Input and Output Impedance Conversion Question

I have to design a matching network for BGA7027 at approximately 870 MHz. My understanding goes that I should convert the S-parameters given in the datasheet to Z-parameters, from which I find Zin and ...
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2answers
2k 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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1answer
59 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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0answers
639 views

import touchstone file into ltspice [duplicate]

Does anyone know how to import Sparameter (touchstone) files into ltSpice and how to use them? I have downloaded s3p format file, but I don't know how to use it. I cant find any information in the ...