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 ...

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Impedance matching with only capacitors?

I need to do impedance matching for 33 + j32 ohm source and 16.5 + j0 ohm load. The copper traces adds 99 ohm impedance and 20 degree electrical length. According to smith Chart below, I need to use ...
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0answers
29 views

What is a Magnetically Insulated Transmission Line? [closed]

What is a Magnetically Insulated Transmission Line (a MITL)? It would be nice to see diagram and some mention of the importance of the shape of the device.
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2answers
48 views

Which of these Stripline Impedance Calculations is correct?

Different sources are giving me drastically different characteristic impedance values, and am hoping someone will verify them for me. Generally, with microstrip, I start with an online calculator to ...
3
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0answers
40 views

Balun/matching network question

I am having problem to verify what an app note (AN068) explains to calculate Balun values. I would appreciate if someone could tell me what/where am I doing wrong? The summary of the RF part: Blue ...
3
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1answer
57 views

Transmission Line Impedence Matching basics

From what I understand, matching a load to a transmission line means that no signal is reflected from the load, which means that at the two sides of the connection point between the load and the ...
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1answer
30 views

How is the voltage and current plot for a matched transmission line constant?

When the transmission line is terminated with a matched load the voltage on the line is given by V(z)=E e^(jβz). where β is the phase constant of the line. 1)How is the voltage plot a constant for ...
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1answer
57 views

How to picture sinusioidal wave in transmission line(electrical circuit in general) ?

I have a friend who keeps asking how does a sine wave flow in transmission line. I've tried explaning him that it is the folw of charges in either directions but he isn't convinced yet . Can somebody ...
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4answers
86 views

Why do transmission line equations use current through inductor rather than capacitor?

I could not fit the title in I actually wanted which was this: In the transmission line equations why is the current difference either side of the inductor used in the capacitative current drop ...
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1answer
40 views

Power management at thermal power station

I have weird question, but I hope somebody can give at least hint what should I read to understand the concept. Imagine situation: There is thermal power station and a city that takes power from ...
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2answers
64 views

Waveguides: How can you propagate at only one frequency?

In a rectangular waveguide, we know we can find cut off frequency as a function of mode and geometry. Is there a way to design the waveguide so to ensure that we can limit the frequency of ...
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1answer
50 views

coplanar transmission line on both sides of a four layer board

I am designing a four layer board in which i have to run two 50 ohm traces one at the top and other at the bottom side of the board. I have decided to use Coplanar wave guide for both the traces. I am ...
3
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2answers
82 views

TTL Long Distance Transmission Alternatives

I am working on a system that gets data from a sensor via a TTL connection. Currently, the data that is gathered from the sensor is sent to another part of the system via a set of modems. The ...
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0answers
34 views

TV antenna problem: Transmission line problem

I have to solve the following problem: A TV antenna lead-in wire 10cm long has a characteristic impedance of 250 \$\Omega\$ and is open-circuited at its end. If the line operates at 400 MHz, determine ...
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0answers
30 views

Voltages in a transmission line network

I have been using S parameters (and T parameters) to understand the behaviour of transmission lines with inline components, and this has worked very well. Is there a way to use or extend this method ...
2
votes
2answers
111 views

Very long transmission-line design tips

I'm designing a very long transmission line between a master node a some slaves far away connected by a bus where only 3 wires are used: - A DC power supply (24vdc) - B Digital comm - C Ground As ...
0
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1answer
84 views

Sending Signals over a Coaxial Cable [closed]

Recently I've been trying to understand how multiple signals can travel along a coax cable. Indeed, I have already read "How are multiple signals propagated in a coaxial cable?", but it doesn't seem ...
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2answers
60 views

How does the circuit fill up?

I came to know that in transmission line if I send only the phase to the houses and make the neutrals to ground then the circuit works. How does the circuit fill up without having any closed contact ...
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0answers
74 views

How long of a wire and how big of a load can I have for SPI bus?

I have a system where I will connect up to 128 identical magnometer ICs up to an FPGA. I am trying to decide between SPI and I2C for comms. If I use SPI the setup will require 128 + 3 wires IF all ...
2
votes
4answers
124 views

Do transmission lines induce electric or magnetic fields in towers?

Transmission lines have EM fields around them due to the high amount of current. Do these fields affect transmission towers (metal or otherwise)? If so, would it be possible to estimate the current ...
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1answer
51 views

How does the impedance that voltage “sees” while traveling down a tranmission line affect how the current move down the line?

It is well known that the voltage sees different impedances while traveling down a tramission line, and this impedance is a function of the intrinsic impedance of the line Zo and tangent of wave ...
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2answers
74 views

What is actually transformed in quarter wave transformer?

I'm reviewing some stuff on quarter wave transformer for a transmission line but since I have not had any experienced in handling these type of stuff, I am struggling to understand this concept ...
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votes
1answer
52 views

Impedance line matching and component value matching

I have the following circuit for the SIM900's antenna connection, using the A10393 antenna from digikey: In closer look: First of all my knowledge on RF design is not great. My questions now are ...
2
votes
2answers
112 views

When a voltage pulse is sent through an open transmission line, what happens to the voltage at the end of the line when the pulse is reflected?

From what I understand, the voltage doubles since the reflected and incident pulses add up. But then why don't all open terminations have double the source voltage since we can consider the voltage ...
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2answers
152 views

Using attenuators to damp reflections on transmission line?

I have a 3m long transmission line that transmits a 100ns bipolar square pulse every 200us. At the beginning of the coax cable is a pulsing circuit board, that generates the waveform, then it sends ...
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3answers
92 views

Simulate RF transmission lines at Low frequencies

I would like to simulate RF transmission lines in how they propagate, and how impedance mismatches at the end of the transmission line cause reflections and power transfer does not work. It would be ...
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2answers
71 views

Why is the data rate a function of the length of the transmission line?

The length of a transmission line is limiting the highest possible data rate on that line. Why are faster signals more likely to become corrupted on long transmission lines than on shorter ones, with ...
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votes
3answers
237 views

PCB RF Layout Critique: Input on my radio-telescope PCB

I'm attempting to do the board layout for a radio-telescope we're building at one of my jobs. Here is the overall system topology: QRFH is for "Quad Ridged Feed Horn". It's a rather esoteric ...
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votes
2answers
59 views

Why is there no voltage drop along a feedline

This page shows a graph of voltage along a transmission line by distance. Considering the case of a simple purely restive feedline of 50 ohms matched to a load of 50 ohms, I would expect the voltage ...
2
votes
1answer
81 views

Stripline reference plane discontinuity in reference design

According i.MX6 SMART DEVICE SYSTEM of freescale layout board, it uses 8 layers, my question is about the inner layers, they are striplines with a continuos GND plane in one side but in the other side ...
2
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3answers
340 views

Tapping energy from high voltage AC transmission lines

The details are hazy as I recollect this from my nipper days.Many, many years ago. “Persons were charged with stealing electricity by placing a large coil, somehow, near high voltage AC transmission ...
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8answers
449 views

Neophyte question about AC vs. DC (especially for powering a home)

Here in the United States the electricity grid is AC. I have heard that AC allows transmission of power at greater distances with less loss. However, with the advent of solar panels, it would seem ...
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1answer
91 views

The mathematics of saltatory neuronal action potential transmission [closed]

Some time ago, I tried to understand saltatory electrical potential transmission on a myelinated axon but have not found a clear mathematical model of this mechanism. The neuronal signal ...
0
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1answer
402 views

Coplanar waveguide for differential trace calculator

Although there are plenty of free impedance calculators out there, I'm struggling to find one that can solve impedances for a differential pair using coplanar waveguide. Anyone know of any free ...
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0answers
58 views

Impedance matching and calculating reactance

Design a reactive L network in order to provide impedance matching between transmission line of \$Z_o = 300 + j60\$ and an antenna having impedance of \$80 +j100\$ at the frequency of 1MHz. How ...
0
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1answer
35 views

How to find attenuation constant

Propagation constant is in the form P= a+jb (a= attenuation constant b = phase constant) a +jb = ln (x+ jy). How do I separate the real and imaginary part in the RHS so that I can equate the ...
2
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3answers
2k views

Why does the USA use 110V and UK use 230-240V?

Why does the USA use 110V and UK use 230-240V? What are the advantages? Explain me with calculation. Why do they use different frequencies like 50Hz, 60Hz? What is the reason?
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2answers
125 views

Best way to drive long signal cables

What is the best way to transmit analog signals between 100 Hz and 100 kHz over a distance of up to 6000 m with minimum frequency depending loss, the level is 50 uV to max 1V (always less than 100 mV ...
3
votes
2answers
88 views

Finite parallel impedance network general solution

Does anyone know if a finite number of parallel-series impedance has a general solution? I am trying to model a network flow problem that can be described in electrical terms and represented as a ...
3
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2answers
121 views

Finding exact breakpoint location in long wire

How can I find the exact location of breakpoint in my long transmission line? Please help with the methods.
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3answers
285 views

Conductance in a transmission line

I'm just trying to clarify the transmission line concepts in my head. Now wikipedia (that great source of always reliable information) defines the conductance in the transmission line as ...
3
votes
1answer
138 views

RF Circuit (what does capacitor do?)

I'm trying to work out why a 0.7pF capacitor was chosen. The circuit operates at 12GHz. At 12GHz, the capacitor has an impedance of about \$18\Omega\$. Also at 12GHz, ...
2
votes
2answers
69 views

CML signal to ground terminated line or peak sensing ADC for short pulse

I'm currently designing the prototype of a timing instrument. One sensor gives an analog CML (current-mode logic) signal, from an amplifier (ADN2880). One end of the pair is routed to a comparator ...
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2answers
498 views

Why does more bandwidth mean higher bit rate in digital transmission?

I understand that similar questions like this one have been asked before on this site, listed below. However, I am confused about the answers. If I explain what I think I understand, can somebody ...
2
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2answers
213 views

Minimal distortion in transmission line

In a transmission line, the condition for minimal distortion (caused by the line) are when (R/L = G/C) in the line, right? However, I don't see any reference to that in any application notes or ...
3
votes
1answer
141 views

1/4 wavelength case in transmission lines

I have studied that in transmission lines, if λ is the wavelength of the signal and L is the length of the conductor, then at L=λ/4 the transmission line act as an open circuit. So if we are ...
1
vote
1answer
120 views

Designing RJ45 connector to have 100Ω differential impedance

I'm designing two pairs of connectors that have same layout as RJ45 (just 2 inner pins) to have 100 ohm impedance deferentially. Are there tools that allow to calculate impedance or ...
1
vote
1answer
84 views

Radio antenna isolating transformer

I need to isolate galvanically my antenna from my RF transceiver. For this I have been recommended a transformer, I select a 1:1 transformer operating in high frequency range. Is it enough to wire it ...
0
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0answers
533 views

Plotting reflection coefficient magnitude vs frequency in MATLAB

I am trying to plot a function (t) with respect to w in MATLAB. However, the output that I am seeing is showing 0 for all w within the defined range. This is not what I am supposed to be seeing. The ...
0
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0answers
57 views

Circuit that behaves as a long transmission line. Any ideas? [duplicate]

I am in need of a circuit that would replicate the behavior of a very long coax cable (miles long). Namely, I am interested in how it would distort a relatively low-frequency signal and how it would ...
0
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0answers
40 views

Applying Transmission Line Theory To Plane Waves

I'm working on a project for my E&M class. Our goal is to use transmission line theory to design a "stealth" dielectric layer for some sort of aircraft. I can assume the radar wave is incident ...