What is Reflection coefficient: Definition and 42 Discussions

In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected wave to the incident wave, with each expressed as phasors. For example, it is used in optics to calculate the amount of light that is reflected from a surface with a different index of refraction, such as a glass surface, or in an electrical transmission line to calculate how much of the electromagnetic wave is reflected by an impedance. The reflection coefficient is closely related to the transmission coefficient. The reflectance of a system is also sometimes called a "reflection coefficient".

Different specialties have different applications for the term.

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  1. Graham87

    Quantum mechanics - finite square well

    In a) I get that T should be largest where V_0 is least wide, because when V_0 is infinitely wide the particle would be fully reflected. But I don't get how height in b) and energy levels height in c) correlates to T and R. Is it because of their k? I get the opposite answer from the correct...
  2. mcas

    Evaluate reflectance of an aluminum mirror

    Note: for some reason frequency on this lecture is indicated by \omega. I wanted to calculate the reflectance using one of these equations that were given to us during the lecture: R=1 where \omega < \omega_p...
  3. T

    Ratio of total refelected intensity compared to incident intensity

    Diagram Calculations as follows $$\frac{I_{total \: Reflection}}{I_{Incident}}=\frac{I_{R_1}+I_{R_2}}{I_0}*100=\frac{R*I_0+(R*T)*I_0}{I_0}$$ Subbing in the relevant equations given in the question $$\frac{I_{total \...
  4. J

    Radar Cross section Vs Reflection Coefficient

    I am working on HFSS and designing Antennas for LOW RCS , in all previous works they calculate the S11 parameter for the unit cell then make an array form this unit cell and calculate the RCS , my question is what is the relation between S11 and RCS and why we calculate S11 for the unit...
  5. T

    Wall thickness vs frequency.... sound isolation

    When sound hits a wall,part of it gets reflected and part of it gets transmitted due to acoustic impedance difference between solid and air. My problem,and point of this question is that having material or gas impedance number is completely useless unless we know the frequency and wall...
  6. D

    Meaning of the FFT of a Poynting Vector integral, reflection coefficient

    Hello, For calculating the mean power at a specific cross section of a waveguide, one can calculate the mean value of the temporal function of Poynting Vector, P(t), where P(t) is the ExHy-EyHx. Note that I am not talking about phasors or a sinusoidal state. If I integrate over the waveguide...
  7. Alvis

    Not a homwork problem, Fresnel Equations

    Homework Statement I was just curious, I know you can derive the critical angle using Snell's law..but could you use it using the Fresnel Equations of reflection, both of them? Homework Equations |r|=1 internal reflection of light...
  8. J

    Fresnel reflection coefficient for Second Harmonic Generation (SHG)

    Hello everyone, this is my first post so I don't know whether or not this is the right thread to be asking this question (if so I am sorry). I am currently working on my thesis where I am determining the thickness of a GaN crystal through second harmonic generation. However in a article...
  9. D

    FLP: Derivation of reflection coefficient

    In Vol. I Ch.33 of Feynman's Lectures (http://www.feynmanlectures.caltech.edu/I_33.html), 33-6, the reflection coefficient as a function of angle was derived. I am confused about the part where it said the component of A perpendicular to B (Acos (i+r)) has the right polarisation to produce B...
  10. Danny Boy

    I Why is reflection coefficient defined this way

    In Griffith's "Introduction to Quantum Mechanics, second edition" he states: For the delta-function potential, when considering the scattered states (with E > 0), we have the general solutions for the time-independent Schrodinger equation: $$\psi(x) = Ae^{ikx} + Be^{-ikx}~~~~\text{for }x<0$$ and...
  11. nmsurobert

    Plotting reflection coefficient

    Homework Statement plot the magnitude |r| of the reflection coefficient as a function of incident angle from 0 to 90 degrees with a step size of 1 degree for the following cases: (ill only post one) A transverse electric plane wave in incident from air to glass Homework Equations r = (n1cosθi...
  12. B

    Transmission line and infinite reflection coefficient

    Hello, I am taking some microwave engineering courses and was trying to explain the concept of reflection coefficients to my friend, but he asked me a question I am unable to answer... So we know that given a transmission line with characteristic impedance Z_0 terminated with a load impedance...
  13. I

    Potential barrier, reflection coefficient

    Homework Statement Electrons are pushed into a grounded metal tube A by the kinetic energy of 100 eV. After having gone through the tube it passes into another tube, B, at some distance from A. Tube B is kept at a potential of -50V. Calculate how many of the electrons are reflected back into...
  14. merlyn

    Reflection Coefficient: Steps 4 to 5 Explained by Drforbin

    Hi all, Great forum. I really don't know if this is the proper place for this, so if it is not please forgive me. I have been researching reflective coefficients in transmission lines. I understand everything except steps 4 -> 5. Perhaps it is a lacking in my math skills but could someone show...
  15. lilknaap

    Reflection coefficient S11 vs Resonator animation

    Hello, I'm trying to do an animation of a photon being absorbed by a resonator vs. the corresponding S11 plot being plotted against frequency. Can anyone give suggestions on how to go about this. As the photon goes through Vin, at other frequencies it will be reflected and probed at Vout. This...
  16. G

    L Impedance matching network problem

    Hello. The attached image is L impedance matching network, use for impedance matching between source and load impedance. The calculation shows that in this circuit, load impedance Rp sees whole impedance (equivalent impedance) of the source impedance and reactive components as matched to...
  17. wood

    Quantum - determine reflection coefficient

    I am working through a past exam paper and this one has me stumped 1. Homework Statement Consider a particle of mass m with kinetic energy E incident from the left upon a step-up potential: $$U(x)=\begin{cases} 0 & \quad \text{for } x <0\\ V & \quad \text{for } x>0\\...
  18. A

    Fiber Bragg Gratings Reflection Co-efficient

    I am studying fiber bragg gratings for a project. I read the couple-mode theory and came across a plot of the reflection coefficient v/s wavelength used which had a global maxima at the Bragg wavelength. The plot was drawn for a constant value of the coupling constant κ. I don't understand this...
  19. W

    Clockwise rotation of the reflection coefficient w/ frequency

    It is always considered that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure. It must...
  20. K

    Reflection coefficient calculation

    Hi there, I am wondering how to calculate the reflection coefficient of walls upon incident light versus wavelengths,, thanks
  21. C

    Transmission Lines: Reflection Coefficient vs Frequency

    Hey guys - I've been using this website to study transmission lines. (great study aid - posting for others to use. Great for smith charts) However, I've noticed this graph they have for load matching: I'm having trouble finding or understanding a relationship for reflection vs frequency...
  22. ShayanJ

    Calculation of reflection coefficient

    I've got a problem asking for the reflection coefficient of a system consisting of a ideal conductor covered with a thin layer of lossless dielectric. I just don't know what to do.How can I do it? Thanks
  23. W

    On the clockwise rotation of the reflection coefficient with frequency

    It is well known that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure. It must appointed that...
  24. E

    Amplitude reflection coefficient for high to low refractive index

    For a wave traveling from a medium with refractive index n1 to n2 with n2 > n1, the amplitude reflection coefficient is given by: r = (n2 - n1)/(n2 + n1) Consider a beam of light passing through a single pane of glass. There is a reflection at the front surface of the pane, with the...
  25. F

    Transmission line reflection coefficient

    Hello, I am looking at the following calculation for the reflection coefficient of a transmission line using the formula ((ZL - ZO) / (ZL +ZO) I can understand it all apart from the last part (0.355e^j). Can someone please tell me how that figure was gained from (-0.354 + 0.030j) (216 + j15...
  26. S

    Solving schrodinger, reflection coefficient

    Consider the potential V(x) = \begin{cases} 0, & x < -a & (I) \\ +W, & -a < x < a & (II) \\ 0, & x > a & (III) \end{cases} for a particle coming in from the left (-\infty) with energy E (0 < E < W). Give the solution to the Schrodinger equation for I, II and III and use these to...
  27. R

    Determining the Magnitude & Reflection Coefficient at 10 GHz

    A radar of 10 GHz produces an electromagnetic plane wave. Conductance is 4 S/m and dielectric constant is 81. How do you ding the magnitude and reflection coefficient? Also the percent of the incident energy that is reflected?
  28. T

    Solving Reflection Coefficient for Step Potential: Why B ≠ 0?

    Homework Statement I'm working through a step potential and I am confused as to why one of the coefficients doesn't go to zero. V(x) = 0 when x < 0; V(x) = V_not when x > 0; a. Calculate reflection coefficient when E < V_not I can solve the reflection part, it is a step towards it...
  29. O

    EM reflection coefficient off a conducting plane

    Let's say there is a conducting plane of conductivity \sigma. Boundary conditions for above and below such plane are: E_1^t = E_2^t (D_2 - D_1 ) \cdot n = \rho i.e. tangential components of E field are continuous and perpendicular components of D are discontinuous because of surface charge...
  30. N

    Two definitions of wave reflection coefficient

    The waves book by A.P.French gives two characterizations of the reflection coefficient for a 1-D traveling wave encountering an interface between two media. On one hand, he writes R = \frac{v_2 - v_1}{v_2 + v_1} where v_i are the wave speeds in the two media. Later on, he writes the reflection...
  31. N

    Determine Reflection Coefficient & Load Impedance: Slotted Line 150ohms

    A slotted line used on a 150ohm lossless transmission line connected to an unknown load impedance, ZL. The voltage standing wave ration is found to be equal to 3. The distance of the first voltage maximum from the load is found to be 9 cm, and the first voltage minimum is located at 3 cm from...
  32. genxium

    Engineering How can I understand reflection coefficient for a certain circuit?

    How can I understand "reflection coefficient" for a certain circuit? Homework Statement I'm a beginner in RF circuit, though I've learned something about low frequency oscillator design, some new concepts still confuse me a lot, like the "reflection coefficient". I google it and found...
  33. M

    Reflection coefficient (osmosis)

    hello ppl, i have a question about the reflection coefficient... since the RC indicates the permeabilty of a membrane for a specific molecule...doesnt that mean (If the RC between 0 and 1) that the concentration of that molecule on both sides of the membrane will become the same after a while...
  34. R

    What is the reflection coefficient on a transmission line at a resistor halfway?

    Homework Statement If I have a coaxial transmission line, with a resistor halfway through, and another resistor at the end, how do I calculate the reflection coefficient for the spot where the resistor is halfway? Here is a diagram of what I mean. Dashes and dots are are the lines, and }...
  35. K

    Reflection coefficient of the step function potential

    Homework Statement Consider the step function potential: V(x) = \{ \begin{array}{*{20}c} {0,(x \le 0)} \\ {V_0 ,(x > 0)} \\ \end{array},Caculate the reflection coefficient,for the case E<V0,and comment on the answer Homework Equations - \frac{{\hbar ^2 }}{{2m}}\frac{{d^2 \psi...
  36. H

    Reflection coefficient of step potential

    why reflection coefficient R=1 in step potential though there happens transmission also as a negative exponential when E<V0
  37. T

    Step potential - question about reflection coefficient

    Hi. I've been trying to understand the phenomenon of step potential, when energy of particle E is higher than the potential V. Then we have solution on both sides of boundary in the form of wave functions... Is the reflection coefficient in this case simply (E-V)/E ?? Can anyone show me a...
  38. V

    Value of Voltage Reflection Coefficient

    hi i was studying the "wave characteristics of transmission lines". while considering the lines with resistive termination, the term "voltage reflection coefficient(VRC)" came. With reference to the book, "Field and Wave Electromagnetics", by David K. Cheng, the following expression was...
  39. F

    QM binding energy and reflection coefficient

    Homework Statement consider a potential given by V(x) = infinity x < 0 = 0 x > a = a negative function of x in between suppose it is known that the interior wave function is such that (1/u) (du/dx) at x=a = f(E) a. what is the binding energy of a...
  40. C

    Calculating Reflection Coefficient for a Potential Well

    Homework Statement A potential well with V(x)=0 for x<0 and V(x) = Vo for x>0. The particle has energy E greater than Vo and is incident from the left side. Calculate the reflection coefficient. Homework Equations Relfection coefficient is given by R= (B*B)/(A*A) The Attempt at a...
  41. S

    Reflection coefficient at a copper boundary

    Homework Statement Calculate the reflection coefficient of copper for radio waves at frequency 50Ghz and yellow light (wavelength = 0.6 micrometers) Homework Equations Reflection coefficient: R = E(r)^2/E(I)^2 = (1-n/1+n)^2 Where E(r) is the electric intensity of the reflected wave...
  42. J

    Transmission coefficient and the reflection coefficient

    I tried to work out the transmission coefficient and the reflection coefficient for a case similar to the one referred by this website: http://www.chembio.uoguelph.ca/educmat/chm386/rudiment/models/barrier/barsola.htm but instead this time, I reverse the situation and now, that particle...
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