Questions tagged [transmission-line]

A transmission line may refer to a cable or assembly that is designed to carry radio frequencies and must consider the wave nature of the signal. Coaxial cable is an example of a transmission line. It may also refer to high-voltage power transmission lines, used to transfer power from generating stations to consumers.

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Is it possible to add a component with an arbitrary impedance matrix to LTSPICE?

I would like to use the following workflow: Simulate the S parameters of coupled transmission lines in an electromagnetics tool (Sonnet etc.). Convert to impedance matrix if necessary. Plug the ...
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How can the Earth be used as a return path? Wouldn't the signal just dissipate after reaching the destination?

I was reading an academic document and I came across this statement: Telegraphy, 1747 (a singe-wire line with the Earth as a return conductor – the first transmission line) I can't imagine how that ...
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What does \$\beta\$ represent with respect to the length of a transmission line?

The picture below shows the ABCD parameters for a transmission line of length \$l\$ from this video. Question: What does \$\beta\$ represent?
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Can someone get electrocuted by holding one of the 3 phases in overhead transmission/distribution lines? [closed]

Three-phase transmission/distribution lines
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Interpretation of Generation and load power at a bus and understanding of slack bus

I was going through the IEEE 14 bus system data from [here] (https://ijireeice.com/wp-content/uploads/2013/03/IJIREEICE2E-a-shkti-Computation-of-final-21.6.14.pdf). I know that there are three type of ...
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Measuring the reflection coefficient \$\Gamma\$

I want to measure the reflection coefficient. I have the following circuit: With these measurements I get the following graphs: Is the reflection coefficient the negative peak of the RED signal ...
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Why is the change in reactive power not equal to the line reactance drop?

I am working on an equivalent network of a two bus system right now. I know the \$P\$, \$Q\$ and power factor at Bus 2. Bus 1 is taken as a slack bus (\$V = 1 PU\$, \$\delta\$ = 0). Using iterative ...
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Will the reflection from the load end of a transmission line affect the behaviour of an ideal voltage source?

Consider a transmission line with characteristic impedance of Z₀ and electrical length of λ/4. One end of the transmission line is terminated in a load of impedance (lets assume) 2Z₀. The other end is ...
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Why is electrical stress higher on the insulator string near the transmission conductor? [closed]

From my observations, it is because of the electric field around the conductor. As we go far from the conductor, the electric field starts decrease. That is why there is also unequal voltage ...
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Modeling a transmission line

I want to simulate a transmission line in PSPICE, however I ran into a problem. I got floating nodes error (I looked it up and I was suggested to put a ground on the far side of the transmission line ...
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Power combiner for I-Q signals in a transmitter

I have a transmitter project to implement. Part of the project is to combine an in-phase and an out of phase (90 degree difference) signal with a center frequency at 3.5GHz. I figured I could ...
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PCB Routing Considerations for multiple USB Port Types for USB 1.1 Full Speed

I wanted to make a device that has a USB A and a USB C connector on apposing sides of the PCB, similar to the attached image. These USB connectors would be connected to the same USB port, the MCU I ...
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Why does the signal have to travel a full round-trip before being captured by the receiver in reflected-wave switching?

Reflected-wave switching from Wikipedia contains the following paragraph: If, on the other hand, there is no termination at the end of the microstrip, and the pulse encounters an open circuit, it is ...
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Rise time and clock frequency: when does it start biting me?

I have spent quite a bit of time reading (mostly the questions and answers on here) about rise times of square waves and how they can cause transmission line effects (reflection, ringing, etc.). ...
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Resistance vs capacitance of conductor

Suppose we have a wire which transmits power. Is there a direct relationship between the resitance (or conductance) of the wire/m and the capacitance of the wire/m? Or they are independent of each ...
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Extend range of BLE devices

I would like to extend the range of two BLE devices. The first one is a VR BLE controller with a monopole pcb antenna. The second one is an ESP32 Tinypico with a chip antenna. I bought two pcb ...
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I need help understanding what the total Impedance in a delta connection is

I'm trying to upskill by teaching myself electrical engineering. I already have a degree in Theoretical physics and Pure mathematics so I don't mind math heavy answers and don't find the math's of the ...
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How to calculate the Change in Reactive Power in a Transmission Line

I am currently calculating the Reactive Power through a Transmission Line. To me, the given values are $$P_S, Q_S, V_S$$ . I have to find a so-called "Reference" Reactive Power for which $$...
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common ground issue in signal transmission?

I am designing a device that output analog voltage in the range of -5 V to +5 V representing a certain measurement (single-ended earth grounded). My plan is to use a regular BNC cable, (earth ...
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How long can a transmission line with proper impedance matched be routed?

Would like to know the maximum length that I could route a transmission line for USB3.0 (SuperSpeed differential lines) and USB2.0 (DP/DM) in a proper impedance matched line at 90 ohms? There is some ...
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Voltage along transmission line with scattering parameters and VSWR given

A transmitter is connected to an antenna with a coaxial cable with length \$l=1.5 \:\text{m}\$. The characteristic impedance of the cable is \$Z_0 = 75 \: \Omega\$ and the scattering parameters are \$\...
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Can I use vias and long trace between processor and 24MHz crystal?

I have a situation where I can't put crystal (24MHz) close to the processor pin. As you see on the layout the trace between crystal Y1 and processor pins 46 and 47 is about 13mm and there are two vias ...
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Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?

In an experiment the cutoff frequency of a lumped transmission line is determined by measuring the ratio of the output/input voltages. The lumped transmission line is a ladder network of 40 capacitors ...
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SPI clock skew prevention

I have a quick question about the clock skew. Does the implementation of SPI account for clock skew? If the data is sampled at the first register and transferred at the last register, ideally when ...
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Transmission Line Differential Equation

I was reading the transmission line chapter of Engineering Electromagnetics by Buck and William H. Hayt. I don't understand why the following is true: $$\frac{\partial{^{2}V}}{\partial{z}^2}=LC\frac{\...
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Deriving power formulas for transmission lines

I'm trying to derive formulas for active power (\$P_s\$) and reactive power (\$Q_s\$) at the sending end of a transmission line shown below: Where: \$E_s\$ and \$E_r\$ are voltage magnitudes \$X\$ is ...
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Placing the BPF and impedance matching on the output and on the input

I am working on solving a problem, namely I need to add input and output matching to my circuit and I am not sure where I should put them. Additionally, in the circuit I want to use a bandpass filter ...
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Phase Constant of Transmission Lines when R, G, L and C values are unknown

A lossless transmission line of length 0.57 m is connected to a vector network analyser. When terminated in a short circuit the input impedance was measured to be: Zin (s/c) = j45 Ω. When terminated ...
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Lossless quarter wavelength transmission lines

so my lecturer released a past paper with the answers and I have no idea how he got the answer to this question. Please could someone explain it to me? Thanks. The question is: A lossless quarter-...
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1 vote
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When does one have to take cable capacitance into consideration?

When feeding an RF signal to a coaxial transmission line, when do you have to take into consideration the capacitance of the cable? I am working with a 36 MHz signal. The total cable length is ~3 ft (...
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Trace capacitance vs telegraphers equation

I haven't taken a course on transmission lines or RF so bear with me. Using EM we can calculate the capacitance and inductance of traces. I'm somewhat confused on the value of this calculation, though,...
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Standing waves in dipole antennas as receivers

I am new to antennas design. When we use antenna as transmitter due to the open air at the end of the antenna we get full reflection of the current and voltage waves. However, when we use it as ...
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Elements of the amplifier - application and operation

I have a problem with a power amplifier from this application note. I am wondering about the elements shown in the circuit in the "Application Circuit" section. Can these elements be ...
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Problem with S parameter calculation

A load of 50Ω is connected in shunt in a 2-wire transmission line of Z0 = Ω 50 as shown in the figure. The 2-port scattering parameter matrix (S-matrix) of the shunt element is: Method 1 The line is ...
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Help needed with determining PCB trace termination for µC/SDRAM interface

I am trying to figure out whether I need termination resistors for my PCB routing between a µ-Controller and an SDRAM (IS42S32800J-6BLI) that I plan to clock at 166 MHz. According to Table 72 of ST's ...
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Coaxial Cable vs Shunt, path of least impedance

The website LearnEMC.com has a page called Identifying Current Paths which contains the following graphics. The graphic on the left shows a coaxial cable arranged in a "U" shape, with a ...
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2 answers
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Analog versus digital (I2S) audio transmission over 1-2m

I need to get a microphone signal to a microprocessor about 1-2m away via cable and I need it to be digitized at some point in this chain. I'm looking for a solution that draws something on the order ...
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How do you calculate the ABCD constants of a transmission line

[question I've been trying to solve this question for a few hours now and this is what i ve gotten so far from scouring the internet for similar questions inorder to be able to solve mine. My question ...
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1 vote
1 answer
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Transmission Line Power Flow

Background: So, I recently watched Veritasium's video, "The Big Misconception About Electricity" and EEVblog's response to it. Here is the circuit in question: I think understand why the ...
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Why do we need to use transmission line theory?

I just started to learn transmission line theory. I'm still confused about a lot of things. Every source says that we need to use transmission line theory when the length of the wire is 1/4 or longer ...
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Guideline for Impedance Matching (simplified cases)

Dealing with impedance matching of RF networks one facing two common techniques: (a) maximize power transfer (b) minimize reflexion of signal waves In this question I have tried to develop some kind ...
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9 votes
4 answers
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How long does it take for energy to propagate in a circuit?

The premise In a recent video by the pop-sci channel Veritasium, the concept of the flow of electricity and energy transmission in a circuit was discussed. In that video a thought experiment is ...
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Maximum power transfer and minimization of signal reflection: When should what be applied

Impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal ...
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3 votes
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Maximum power transfer and minimization of wave reflection: Understanding the difference on intuitive level

It is well known that there are two usual methods in impedance matching: if we have a network consisting of a source with impedance \$Z_S\$ and load with impedance \$Z_L\$ then we have two options to ...
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Is it ok to extend 16V AC output with 12V heavy duty electrical cable?

I have a AC 240V to AC 16V transformer to drive my gate opener. But the 240V power outlet is far from the gate. Is it ok to extend 16V AC output by using 12V heavy duty electrical cable? Transformer: ...
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How to terminate branches in a transmission line

some research has unfortunately not led to a clear result. Branches in transmission lines are not desirable, but if they are unavoidable the question arises how to properly terminate the individual ...
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Remote Sense Self Adjustable Power Supply

I been looking for an off the shelf power supply that can adjust its output voltage to compensate for losses, in my case in transmission line. Searching on DigiKey, I narrowed down my search to power ...
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Voltage drop impedance value

A single-phase circuit 60Hz transmission line is 45 miles long. Transmission line impedance z = 0.5 Ω/mi. The load on the transmission line is 75MW at 115kV with a 0.90 lagging power factor. Calculate ...
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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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What is the meaning of Ω.mi?

In transmission line I see Ω.mi. I know that Ω/mi gives the value of impedance per mile. But Ω.mi gives impedance times mile!! Assume a conductor has z = 1 Ω.mi For a transmission line of 10 miles ...
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