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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 waves cannot propagate in a wavwguide?
In a waveguide, transverse electromagnetic (TEM) waves cannot propagate because they require both electric and magnetic field components to be present and perpendicular to the direction of propagation. In a waveguide, the fields are constrained to be transverse to the direction of propagation, which is not possible for a pure TEM wave.
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
What is TE and TM modes?
TE (transverse electric) and TM (transverse magnetic) modes refer to different types of electromagnetic wave propagation within a waveguide or transmission line. In TE mode, the electric field is perpendicular to the direction of propagation, while in TM mode, the magnetic field is perpendicular to the direction of propagation. These modes have distinct characteristics and applications in the field of electromagnetics.
The waves which cannot be transmitted in waveguide are?
The waves that cannot be transmitted in a waveguide are those that have a wavelength longer than the cutoff wavelength of the waveguide. These waves are unable to propagate efficiently within the waveguide due to the cutoff phenomenon which restricts their transmission.
Why TEM wave cannot propagate thorough a rectangular waveguide?
A rectangular waveguide supports transverse electromagnetic (TEM) waves only if its transverse dimensions are infinite. In a waveguide with finite dimensions, TEM waves cannot exist due to the need for both electric and magnetic field components in the direction of propagation, which is not possible in a waveguide with finite cross-sectional dimensions.
What is the dominant mode of microstrip line?
The dominant mode of a microstrip line is the mode where the electric field is primarily confined between the strip conductor and the ground plane. This mode is known as the quasi-TEM (quasi-Transverse ElectroMagnetic) mode.
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.
Which wave cannot exist inside wave guide?
A transverse electromagnetic (TEM) wave cannot exist inside a waveguide. This is because TEM waves have both electric and magnetic field components perpendicular to the direction of propagation, which cannot be supported within a waveguide due to its geometry and boundary conditions.
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
