Waveguide Definition and 103 Threads

Hello everyone, I'm trying to solve a problem but I want to find a simpler way if possible. The basic idea is that I would have one waveguide, for simplicity I will just take a slab waveguide. However instead of being constant there is a point at which the distance between the slab suddenly...

Hi, I'm new on the forum and I would like to start with a question. I've searched for a reply in old posts with no success. If you can help me to find an answer I'll be very glad. Talking about optical modes inside a waveguide. If a waveguide support two different modes, say TM and TE mode...

Hello, If a rectangular waveguide (or square well, etc) is centered at x=a/2, y=b/2, solution (e.g. for TE mode) is: H = Ho Cos(m*pi*x/a) * Cos(n*pi*y/b) (n,m = 0,1,2,...) So for TEn=0,m=1, H = Ho Cos(pi*x/a). If it is centered at the origin, you get even and odd solutions: H = Ho...

This is a question I've been trying to figure out. I'll try my best to formulate it, so apologies if it's a bit ill defined! Suppose you construct a finite parallel plate waveguide of PEC(perfect electrical conductors) and PMC(perfect magnetic conductors) so that the top/bottom plates are PEC...

Hi everybody, that's my question, I have been measuring the standing wave pattern within a waveguide (X band) using a slotted line, I put a short circuit termination and the theory said that we expect a rectified sine, but I don't get that, my result is in the picture I can't explain my...

Title pretty much says it all. In EM waveguides (rectangular, circular, what have you), I understand there are various "modes." I'm gathering that these represent specific, discrete solutions to the Hemholtz equation, and therefore there are only specific frequencies that will propagate? What...

Homework Statement OK, so, a compounding of my knowledge so far. - A waveguide is a conduit for EM waves. - They can be parallel plate (infinite), circular, or as I'm looking at - rectangular. - Speed of propogation is limited by skin effect - the higher freq, the thinner the skin & so higher...

Hi all, I'm a little confused about Bloch modes vs. waveguide modes of a single waveguide and was wanting some pointers. I read that Bloch modes are results of the wavefunction of a particle (usually, an electron) placed in a periodic potential. In the case where we have an array of cylinder...

Hello I am using Rsoft- Beamprop program to do some simulations on a multilayer waveguide. Can anyone please help me to interpret the graph (simulation results) attached. Explanation of the graphs :- I have done some calculations to find the output power (wavelength = 633micrometer) through...

Let λ be the wavelength of an EM wave in empty space. Let a x 0.5*a be the dimensions of the cross-section of the waveguide. Can I use a = 0.35*λ ? It should be possible, it corresponds to θ = π/4, where θ is the effective angle between the long axis of the waveguide and the direction of...

Homework Statement How to solve this problem? An air-filled waveguide of rectangular cross-section (1 cm x 2 cm) is used to carry EM waves at a frequency of 10 GHz. Show that only the TE01 mode can be used? I tried to find the cut-off frequency ( 7.5GHZ) and is that enough to...

Hello! You can find in the picture attached a parallel plate waveguide which has an a1 height before the step and an a2 height after the step. The plates are perfect conductors and the step is ideal. I can't determine which physical quantities are continuous across this discontinuity. Suppose...

Hello! This is the first time I write in the forum. I hope to be fully in-topic. I'm dealing with a rectangular waveguide discontinuity: a perfect-conductor plane orthogonal to the propagation direction, with a circular aperture in the centre of the guide section. The structure is symmetrical...

Homework Statement Derive the boundary conditions for the B field imposed by divB=0I'm lost with this question, I don't really understand how boundary conditions work. D.J. Griffiths only really mentions how to arrive at the conclusion that: B_{1}\bot-B_{2}\bot=0 but doesn't outline the method...

Hello: I am passing 1 micron laser light through some semiconductor waveguide devices with my research group. We would like to observe the mode pattern on an infrared camera. The thinking is that if we observe a well defined pattern at the output of our devices, then it will be an indicator...

Hi all- just looking for a few good references deriving the mode structure of coaxial waveguides. I have read through griffiths a few times but was not really happy. further consulted an edition of landau and lifgarbagez, but again came away dissatisfied. While I realize and understand what...

Homework Statement I am doing a 2D COMSOL simulation (RF module) of a rib waveguide of nanometric structure. My question is if there is any rules of thumb of distinguishing when the mode no longer is confined under the rib-structure. Homework Equations None The Attempt at a...

Homework Statement A TE_10 mode is propagating in a rectangular waveguide along the z-axis. If the waveguide is terminated with a perfectly conducting metal plate normal to the z-axis, then 100% of the electromagnetic radiation propagating in the guide will be reflected by the metal plate...

Hi, For experts among you it might be trivial, but I am not exactly "at home" here :confused: so, here it goes: 1.Does the "cut off frequency" in waveguides apply to all incident angles of electromagnetic waves propagation through the waveguide or not. 2. Does the shape of cross-section...

Hi, I am trying to calculate maximum E-field strength in a rectangular waveguide cavity resonator at 1.6GHz. The input power is 200W while the resonator should wsupport TE101 mode. cavity dimensions are 0.131mmx0.65mmx0.134mm (WxHxL) having lossy walls made up of copper with conductivity of...

reflection in a hollow metal waveguide... Hello Forum, when an electromagnetic wave hits a conducting surface there are surface currents generated on the surface itself. These currents are the result of the interaction between the field and the metal. Do these currents radiate their own...

Hi Guys, Most of you guys should heard of Fibre optic gyroscopes. I'm trying to create a gyroscope that send out microwave instead of light source. Is there any program that i can use to create the circuit and simulate before getting hands on. Btw it might or might not work i have no idea...

Homework Statement Show from general considerations that the attenuation of power in the rectangular waveguide (TE10 mode propagating in z-direction) is: P(z)=P(0)exp(-2k''z) where k'' is the imaginary part of the wavevector in the phasor exp(j(wt-kz)) Homework Equations power is...

Homework Statement For a rectangular wave guide the components of E were found to be Ex = A1 cos( k1 x) sin(k2 y) e-i (\omegat-\gammaz) Ey = A2 cos( k1 x) sin(k2 y) e-i (\omegat-\gammaz) Ez = 0 Show that in these equations A1 = -A2 k2 / k1 Homework Equations See part (a)...

I've read in various places on the web and on this board discussions regarding subwavelengths, but I still can't fully comprehend how it's possible for an EM wave to transmit through an aperture and\or encased waveguide that is smaller than the given EM wave's wavelength. I've read about...

Greeting. I am currently investigating the dispersion properties of waveguides. The dispersion of an optical fiber is usually mostly contributed to by the material dispersion. Ignoring any dopant, this is just dependent on the refractive index of silica. It is easy to take the Sellmeier...

Consider an asymmetric planar waveguide with nf=1.5, ns=1.47, nc=1.0. Determine the allowed values of beta for the TE modes in a waveguide with thickness h=7 micrometers. Assume the excitation wavelength is 1 micrometer. Our prof gave us this equation; Beta = (Ko2nf2-Kf2)1/2 Ko...

Explain why a plane electromagnetic wave cannot propagate through a metallic waveguide. I've tried to come up with an answer, but I haven't been able to. I thought metallic waveguides were good since they reflected the propagating wave very well, allowing the wave to move without much loss...

Can someone please explain the difference between Material dispersion and waveguide dispersion?

For traveling waveguide, if the central aperture diameter is constant from beginning to the end, it is known as "constant impedance" where the electric field is attenuated and is diminished by the time wave reached the end of the waveguide . If the central aperture is tapered (larger opening in...

I find it a bit hard to visualize E field and H field inside a waveguide, specially in modes other than TEM. I know E and H are perpendicular to each other and to the direction of propagation. But I need to see some examples or something like a right hand rule. Basically, I am confused.

Homework Statement For a given rectangular waveguide the cut off frequency of the fundamental mode is 6.5GHz. What is the fundamental resonant frequency of a 30mm long cavity made from the same waveguide? Homework Equations Unsure The Attempt at a Solution I would have...

One of my professors made an X-band cavity resonator by putting together, end to end, two X281A coaxial waveguide adapters (n-type) with cut center pins. It works pretty well - but I need some more information. Does anyone know where can I find some more information on this setup...

a waveguide consists of two mirrors separated by distance d, facing each other, the light ray that reflects between them forms angle (theta) with one surface. there is a reflection phase shift of pi. for the light to continue to the end, there must be constructive interference between the...

Homework Statement I'm attempting to find the General solution and boundary conditions for a TE_{m0} waveguide split up into two different materials: a (any) dielectric on the bottom, and a metallic conductor on top. Image attached. Homework Equations General (homogenous) Helmholt's...

[b]1.i need urgent clarification in this regard .waveguides can be modeled as high pass filters.how ever plasma waveguide guides only those waves which are below plasma frequency. why is it so?

Setup: I'm trying to make the band structure for a planar photonic crystal with finite thickness, i.e., a quasi-3D problem. I only want the x-direction band structure. So, I'm using variable floquet periodic BCs for the x-direction boundaries, and 0 degree floquet periodic BCs for the...

Hi, I have the fields for a rectangular waveguide in terms of cartesian components, that is, Ex, Ey, Hx, Hy. I need to convert these to polar components in terms of r and theta. I've done this the other way around, converted a circular waveguide field which was written in terms of r and theta...

Homework Statement For an air-filled waveguide rectangular wave guide with the top and bottom made of PEC and the left wall made of PMC and the right wall of PEC. The dimensions are a=5cm b=3m. Find the dominant mode propagating in this wave guide (a is length and b is the height) Homework...

Homework Statement I have to find the ratio of the lowest TM cutoff frequency to the lowest TE cutoff frequency. Homework Equations The Attempt at a Solution I have derived the general form of the cutoff frequency (which seems to be the same for both). I get the right answer if I...

Homework Statement Consider a wave guide with a square cross section of dimensions a x a. Let the z axis be the axis of the wave guide. Suppose the region z < 0 is vacuum, and the region z >0 is a dielectric with permittivity \epsilon . Write a solution of the wave equations and boundary...

Hi members, am new to antenna field.I would like to know more about polarization in waveguide.As per book,it is stated that TEM wave cannot travel in waveguide.If that is the case how come horizontal or vertical polarization can be achieved.If am wrong,please correct me.Thanks in advance.

Hi, I am doing an experiment to investigate the propagation loss in some nanophotonics structures. The laser light is coupled to the input of the DUT chip via a tapered lensed fiber and the output of the chip is go through a objective then a photodetector. The chip is design for...

Can we model the QM behavior of a particle as the propagation of "probability microwaves" in a generalized waveguide?

I have a perfectly conducting circular waveguide. I want to calculate the time-averaged Poynting vector of a circularly polarised TE mode, ie: H_z = H_0 J_{n}(\rho \chi)e^{in\phi} Where \chi is the appropriate eigenvalue. My result for <S> implies helical energy flow; it has a z...

Homework Statement We have a 1-D optical waveguide of width 2a (with axis z=0), with a propagating wave (propogating in \hat{z}) in the lowest order mode, approximated by: E(x)=ACos(\frac{\pi x}{2a}) We insert a dielectric slab half-way into the guide such that the slab ends at z=0, it...

Homework Statement Consider a vacuum filled infinitely long metal cylindrical waveguide of radius, a. Suppose the fields in the waveguide are as follows: \vec{E}=\vec{E_{0}}\left(s,\phi\right)\exp i(kz-\omega t) \vec{B}=\vec{B_{0}}\left(s,\phi\right)\exp i(kz-\omega t) Find E_{0z} 2. The...

So I know there is an upper cutoff frequency (at least in the microwave band) for a rectangular waveguide. However for the life of me I can't find why one would exist in the equations, the internet is full of references to it based off of the dimensions of the waveguide, but I'm curious whether...

As part of my project I want to calculate the theoretical value of the best thickness of cladding to use on my waveguide to prevent light from leaking through the cladding to the next layer, I'm aware I need to play with Maxwells equations and it's pretty much particle in the box where I'll have...

I am solving the wave-equation (more specifically Helmholtz Eq.) in cylindrical coordinates. I've separated the equation into 3 ODE's. - The radial differential equation - The phase differential equation - The z differential equation (direction of which the EM wave propagates) My issue...