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Questions tagged [waveguide]

A waveguide is a physical structure that guides electromagnetic or sound waves. They are most commonly employed at high frequencies such as microwave.

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What differences in terms of fields does a grounded metal and an unconnected metal object have

I previously asked a question regarding absorption and reflections of waves to metal. But id like to know the differences that say a PCB metal pour that is connected to a signals return path, and a ...
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Transmission Lines and Waveguides - How to calculate Intrinsic Impedance?

I have come across a problem when calculating the attenuation due to conductor losses for circular cross sections: A circular copper waveguide has a radius of 0.4 cm and is filled with a dielectric ...
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Transmision and coupling coefficient in waveguide and ring resonator

A simple ring resonator with a bus waveguide is described by: \begin{equation} \begin{pmatrix} B \\ C \end{pmatrix} = \begin{pmatrix} t & \kappa \\ -\kappa^* & t^* \end{pmatrix} \begin{pmatrix}...
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coplanar waveguide impedance calculation and tolerance

The Ublox Sara R5 System Integration Guide I am following states that a 50 Ohm antenna waveguide design is recommended and provides a couple example designs that achieve this using FR4 dielectric. ...
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Identifying monopole antenna with ground connected coil

I can’t find any information on what this design of antenna is called, it has a monopole wire connected to the signal pin of an SMA connector, the coil is connected to ground. The larger diameter ...
josh eanes's user avatar
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Using microwaves to dry a small sample of material - best method?

We have a requirement to use microwaves (no choice here) to dry a small sample of material with a mass not exceeding one gram. It will be placed in a small sealed steel enclosure. First thoughts were ...
Dirk Bruere's user avatar
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From the perspective of a progressive wave, what is lumped impedance? [closed]

This question asks about the meaning of lumped impedance in traveling wave theory. Should lumped impedance be viewed as something like a point charge, a point mass, or a direct delta function? When a ...
Field Wave's user avatar
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Conformal Mapping in Electrostatics: t-plane

In the paper 'Extension of the application of conformal mapping techniques to coplanar lines with finite dimensions' the author uses the t-plane as a intermediate step for calculating the capacitance ...
wave's user avatar
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Interruption in waveguides

I want to fabricate a PE waveguide.I deposited a layer of aluminum with a thickness of 180 nm on Lithium niobate.I lithographed the design of the waveguide,After developing photoresist and etching the ...
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11 votes
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Which stackup to choose for JLPCB FR4 up to ~10GHz

I am aware that 10GHz on FR4 is not ideal, but this is an hobby project and I can tolerate some losses. The 10GHz on the PCB is minimal (probably only a short coplanar waveguide or microstrip with 2 ...
Waldorf's user avatar
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Ansys AEDT and Icepak Simulation

I have designed slotted coax cable based waveguide and FR4 is not getting any heat and even the coaxial cable does not get any heat which I do not understand why. E field as follows, ports include 2kW ...
Nurullah Çetin's user avatar
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Phase velocity non-TEM transmission line

Assuming that a transmission line operates in a TEM or quasi-TEM mode, the phase velocity can be determined from the line parameters (R,L,C,G per meter assuming the RLCG model of a transmission line). ...
waves's user avatar
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Unexpected low characteristic impedance using the JLCPCB impedance calculator

I'm currently designing a PCB that is intended to fan out the 38 pins of a MICTOR connector to every other conductor of an 80-conductor ribbon cable (The PATA type one, that is AWG30 wires with a 0....
Michael Karcher's user avatar
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Circular waveguide excitation for TE11 coefficients

As we can see below, the theory says that A,B coefficients depend on the excitation. I have simulated a circular waveguide. How do I need to excite my waveguide so I will see the A and B coefficients ...
lub2354's user avatar
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Interference of RF currents with a combiner

I am trying to understand what happens to 2 RF currents flowing in separate planar waveguides (such as microstrip lines), when combined with a power combiner. More specifically, will they interfere, ...
Nova's user avatar
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Could a DIY 1 kW portable version of the military non-lethal microwave beam active denial system (ADS) be made?

How would one create a portable 1 kW microwave emitter that projects out a 95 GHz beam to about 5 - 10 feet? What kind of components would be required? I recently came across this fascinating video ...
emtinkerer's user avatar
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How to generate microwave band frequencies like 85GHz? Is there a DIY device or parts kit to do this? [closed]

Let's say I want to build a device that generates and sends out a microwave of some arbitrary specific frequency to a short distance, say 1 - 2 feet. For example, 95 GHz. Is there a straightforward ...
emjunkie's user avatar
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Need help using RF transceiver with RF amplifiers

I'm trying to use the STM32WLE5C8 SoC that is both a microcontroller and an RF radio. For my project I will be using the radio in the 800 - 900 MHz band (high-band configuration for this radio). I ...
Exclose's user avatar
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Help with understanding waveguide dimensions for a pyramidal horn antenna

I want to build a pyramidal horn telescope as a science project but I’m having some trouble understanding the waveguide dimensions. This documentation lists the dimensions of a paint thinner can be ...
Skantzy's user avatar
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Minimum trace distance when using a via fence in a waveguide

I am trying to route several high speed JESD204B signals (up to 12GHz) to a connector and there is very small area for them. The manufacturer design note (p.113) recommends to route those signals on ...
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Effect of surrounding material on microstrip impedance?

If you were to have a microstrip transmission line PCB trace, which then had a dielectric material run completely on top of the PCB track coverlayer. Would this surrounding material affect the ...
Electronics Wizzter's user avatar
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How do I find out the dimensions of a rectangular waveguide given the frequency I want to operate it at?

I want to design a horn antenna to detect the 21 cm hydrogen line. I know how to optimize the antenna dimensions by taking into account some functions that approximate the phase errors and ...
requiemman's user avatar
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Is there a standard that describes the term "coplanar waveguide"?

I look at IEC60050 "International Electrotechnical Vocabulary" standard at section 726 "Transmission lines and waveguides" and searching on the word "coplanar" gives me ...
Arseniy's user avatar
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Why do dielectric waveguides support hybrid modes and metallic waveguides do not?

Can anyone explain to me qualitatively why dielectric waveguides (core and infinite cladding) support hybrid modes (E_z and H_z components in the guided wave), while metallic waveguides cannot? I am ...
Minas Michael Opethian's user avatar
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The field in a waveguide at exactly the cut-off frequency

Can anyone explain to me qualitatively, what kind of field exists inside a waveguide at EXACTLY the cut-off frequency? I would be grateful if an explanation was given about waveguides with metalic ...
Minas Michael Opethian's user avatar
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How can I tell whether a waveguide supports hybrid modes or not?

When studying metallic waveguides, it was taken for granted that the TE and TM (and potentially TEM) formed a complete set, that is, any electromagnetic field in the waveguide could be written as a ...
Adrian's user avatar
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I need help trying to set up a rectangular waveguide in HFSS,

Task: Setup a rectangular waveguide in HFSS using four perfect E boundaries on the side faces of a box and waveports on the end faces of the box. Set up your dimensions so that at the lowest frequency ...
Anim8D Ideas's user avatar
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Where is the azimuth and radial direction on the mode plot

Hello the photo bellow presents TE01 mode. Where on the plot can i see the azimuth and the radial directions? Thanks.
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How to interpret waveguide multi-mode S-parameters in CST

I have a cylindrical waveguide which is excited with two modes in each ports as shown bellow. However I cant see the meaning of S-params shown bellow. photo one shows total isolation(-100dB) While ...
gop664's user avatar
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1 answer
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Why is a microwave oven equipped with a waveguide? [duplicate]

In a microwave oven, the magnetron connects to the waveguide.  Magnetrons produce microwaves, which are guided into the cooking chamber by waveguides. Why don't we directly connect the magnetron to ...
Prerna 's user avatar
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2 answers
135 views

Waveguides and optical fibres

Why at microwave frequency we prefer rectangular waveguides while at optical frequency circular waveguides (i.e. optical fibres). Can we have rectangular optical fibres.
user32834's user avatar
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How to imagine the mathematical expression in the waveguide?

Below we see an example expression for the E-field. It has three components: polarization of the field propagation direction standing wave pattern In the photo below of the field "L" has ...
ron398's user avatar
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2 votes
2 answers
597 views

What is a guided mode?

I am currently reading my text, for my electromagnetics course, and we are discussing guided waves. The text casually mentions the term "guided modes", and never really defines what that ...
Rico's user avatar
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Different 50Ohm-matched condition for different length of metamaterial waveguide

Based on coplanar waveguide, I am designing a meta-material waveguide by inserting lumped-element inductors along the center line. Here are some parameters: Target frequency: 10-20 GHz Size of lump ...
Sandbo's user avatar
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What is the impedance looking into a length of coaxial cable that is short-circuited at the far end and a half wave-length long?

What is the impedance looking into a length of coaxial cable that is short-circuited at the far end and a half wave long? I have been told that this the the basis of what is known as a wave guide &...
Vinmann's user avatar
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Dielectric slab waveguide

let's consider the so called dielectric slab waveguide (references for image and equations: here, page 53): I do not know much about it, I know only that it is a planar guiding structure which is ...
Kinka-Byo's user avatar
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Elliptical polarization and waveguides

It is known that a generic harmonic electric field which propagages in free space has an elliptical polarization (if you want to read the proof, look at this, slides 72 - 99). My question is: what ...
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Engineering very high impedance resonator with coplanar waveguides

I have very little knowledge of electrical engineering, so please understand if my questions are somewhat trivial. I have read that a coplanar waveguide (CPWG) acts as a lumped LC oscillator circuit, ...
Tobarimaru's user avatar
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1 answer
360 views

Can I get the S21 parameter from a one-port open, short and load reading?

I am currently working with a custom rectangular waveguide, which has one port abled to connect to a VNA,(call it port a) but the other side cannot, (its part of a bigger system but for now its only ...
Jacob Giese's user avatar
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Designing waveguide based structure using cst

I am going to start designing waveguide based circulator , hybrid and loads using cst or ansys workbench. I am quite familiar with the design of microstripline and stripline based systems using ADS. ...
MKM's user avatar
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2 votes
2 answers
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Shape of waves in waveguide

What is actually going on in waveguide when the wave is passing through it ? If I am not mistaking , the plane waves are "fed" to the waveguide and there is a cutoff freq above which the waves can ...
MKM's user avatar
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Evaluation of the dominant mode in a waveguide

In a waveguide, the dominant mode is defined as the propagation mode with the lowest cutoff frequency. Now let's consider a structure in which the lowest cutoff frequency occurs for two different ...
Kinka-Byo's user avatar
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1 vote
2 answers
68 views

Geometric spreading of an impulse antenna

I am new to radar and curious about the geometric spreading in free space. I set up an air-coupled antenna about a half meter above the ground, with a large PEC on the ground. Then I adjusted the ...
Juliet's user avatar
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1 answer
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Waveguides Equivalent Circuits

I was reading in a book how to derive the equivalent circuits for TE, TM, TEM modes of a generic ideal (without losses) waveguide. After some computations, it found this equivalent circuit for TE ...
Kinka-Byo's user avatar
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Cut-off frequency in ideal waveguides

it is known that in an ideal waveguide (with a perfect electric conductor and with non-dispersive and non-conductive dielectric) there is a cut-off frequency, for each mode, such that for higher ...
Kinka-Byo's user avatar
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Excitation of a resonant cavity

let's consider this picture in which a cylindrical resonant cavity is excited through a waveguide. I have some questions: 1) Why is it called "Magnetic Coupling"? I thought this excitation simply ...
Kinka-Byo's user avatar
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4 votes
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572 views

How to construct an SMA feedline for a horn antenna

I'm constructing an sma coax to waveguide transition for a horn antenna. Here's a cross-sectional view of what the device will look like I can 3d print the waveguide portion (I use a conductive paint ...
MattHusz's user avatar
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1 vote
2 answers
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Impedance mismatch vs Signal attenuation

I'm currently designing a 50Ω grounded coplanar waveguide (GCPW) which connects an antenna to an LTE modem. My question is: does there exist a standard graph/chart that attempts to generalise ...
amitchone's user avatar
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Calculating dielectric constant of a dielectric sample placed inside a rectangular waveguide [duplicate]

Im trying to calculate the dielectric constant of a dielectric sample placed inside a rectangular waveguide over a range of frequenices. I used WR90 ( X band ).Using the s parameter data (S11 and S21),...
Jithin 's user avatar
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Can anyone tell me how to find permittivity of a dielectric sample using a rectangular waveguide

Im trying to find the material paramters of a dielectric sample using a waveguide(X band) employing the Transmission/Reflection technique. While performing simulation in CST, how to properly orient ...
Jithin 's user avatar