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What is difference between Rectangular Waveguide and Circular Waveguide?
Rectangular waveguide and circular waveguide are metal hollow structure used to guide EM waves. Depending upon their shapes they are classified as rectangular or circular. They are basically a passive microwave device and acts like a High Pass Filter. Rectangular waveguide : It is the earliest kind of the transmission lines. It supports supports TM and TE modes. It does not support TEM waves because it has only one conductor and cannot define a unique voltage. Conductor is filled with a material that has material with permittivity e and permeability m. Cutoff wavelength equation for is define below. λc = 2/ Here, m= number of half-wave along broad side dimension, N= number of half-wave along the shorter side. Circular Waveguide: It maintains a uniform circular cross section along their length. The cutoff frequency is unique for a specific waveguide mode that is assumed to be propagating in a waveguide of a given diameter and determines the lower frequency of the waveguide’s operating frequency range. The cutoff frequency is calculated using the following formula:
Why TEM wave is not supported by hollow waveguide?
Arif Ullah khan utman kheel this is because for conductor E parallel is zero this means that the surface of the wave guide is at equipotential and this potential follow the laplace equation .it means that there is no maxima and minima inside the wave guide . this means that the electric field inside zero . hence the TEM do not exist in wave guide only TE and TM can be exist . if we place some conductor in the wave guide then the conductor inside will not be equipotential and the TEM waves can be exist . like in Coaxial cables
The waves which cannot be transmitted in waveguide are?
The Transverse electromagnetic(TEM) wave cannot be transmitted within a wave guide.
What is the dominant mode of microstrip line?
The line will not support a true TEM wave; at non-zero frequencies, both the E and H fields will have longitudinal components (a hybrid mode).The longitudinal components are small however, and so the dominant mode is referred to as quasi-TEM. kuldeep jaimini
What is TE and TM modes?
Transverse electromagnetic (TEM) is a mode of propagation where the electric and magnetic field lines are all restricted to directions normal (transverse) to the direction of propagation. Plane waves are TEM, however, we are more interested in what types of transmission lines can support TEM.
What is the dissimilarity between waveguide and transmission line?
i am kuldeep b. shukla.this is my ans: Comparison of Waveguide and Transmission Line Characteristics Transmission line • Two or more conductors s eparated by some insulating medium (two-wi r e, coaxi al , microstrip, etc.). • Normal ope rating mode is the TEM or quasi-TEM mode (can support TE and TM modes but the s e mode s a r e ty pic a l l y undesirable). • No cutoff frequency for the TEM mode. Transmission lines can transmit signals from DC up to high frequency. • Significant signal attenuation at h i g h f re q u e n cies d u e t o conductor and dielectric losses. • Small cross-section transmission lines (like coaxial cables) can only transmit low power levels due to the relatively high fields concentrated at specific locations within the device (field levels are limited by dielectric breakdown). • Large cross-section transmission lines (like power transmission lines) can transmit high power levels. Waveguide 1. Metal waveguides are typically one enclosed conductor filled with an insulating medium (rectangular, circular) while a dielectric waveguide consists of multiple dielectrics. 2.Ope rating modes are TE or TM modes (cannot support a TEM mode). 3. Must operate the waveguide at a frequency above the respective TE or TM mode cutoff frequency for that mode to propagate. 4. Lowe r signal attenuation a t high frequencies than transmission lines. 5. Metal waveguides can transmit high powe r levels. The fields of the propagating wave are spread more uniformly over a larger cross-se ctional area than the small cross-section transmission line. 6. L arg e cro ss-sectio n (lo w f r e quency) wavegui de s a r e impractical due to large size and high cost.
Why microemulsions are analyzed by TEM not by SEM?
Microemulsions are analysed in SEM in cryogenic mode. In that mode it is difficult to get a resolution of order of 40-50 nm(which is the typical domain size of microemulsions). So TEM is a better option
Why TEM mode does not exist in waveguide?
for TEM u need to a magnetic field (H) linked to an electric field .for this u need to a J relative to E (E=sigma J). because [curl H = J] but optical fiber is dielectric wave guide and sigma is zero and u only have dD/dt so there isn't H linked to E.
What is the dominant mode of propagation in microstrip line in low frequency approximation?
quasi-TEM
Why TEM wave cannot propagate thorough a rectangular waveguide?
TEM modes (Transverse ElectroMagnetic) have no electric nor magnetic field in the direction of propagation. In hollow waveguides (single conductor), TEM waves are not possible, since Maxwell's Equations will give that the electric field must then have zero divergence and zero curl and be equal to zero at boundaries, resulting in a zero field. BY JITONJA GOGO at THE UNIVERSITY OF DODOMA
How do sem and tem produce images?
SEM, which stands for Scanning Electron Microscope produces images by penetrating the specimen with a fixated beam. This beam is used to scan a rectangular portion of the specimen. Images are reliant on surface processes and they are incomplete, unlike TEM images. TEM, which stands for Transmission Electron Microscope utilizes an electron emission of high voltage. They produce complete images.
What is the meaning of zhu tem?
Zhu tem
