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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Differential Pair Reference Plane Coupling
I am routing LVDS pair on a flex board. The signal is 264MHz. I used Saturn PCB design to calculate width and spacing between conductors. The targeted impedance for diff pair is 100 ohms, which is ...
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46 views
Coplanar Waveguide Calculations PCBS, AppCAD v.s. Online calculators
So lately I noticed that the Coplanar Waveguid calculations of AppCAD (http://www.hp.woodshot.com/) did not give the same result as the online calculators do.
https://chemandy.com/calculators/...
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1answer
41 views
Frequency response of the waveguide
So, I have signal in the waveguide that is transmitted by two modes of radiation, for which the delay is for example \$\tau_1=6\,\text{ns},\, \tau_2=6.5\,\text{ns}\$, respectively. And the energy ...
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94 views
Design of cavity filter
I try to design a Chebyshev bandpass filter for 6 GHz as a coaxial cavity filter. I know that the filter can be designed with the aid of the coupling coefficients between the resonators and the loaded ...
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46 views
Metallic Waveguide Boundary
I've been studying TE and TM modes on waveguides for microwave frequencies.
It basically consists on applying Maxwell equations on a rectangular metallic cavity, with infinite length on \$z\$ ...
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2answers
574 views
Standard 2.54/1.27mm pinheader impedance
I was thinking of using one of the most ubiquitous connectors in the world - 2.54mm pin header. The snag here is that I need to push a relatively high frequency over it 4MHz UART, edge frequency much ...
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66 views
Can I trust these microwave power readings?
So I've got an old Hughes TWT that supplies roughly 20W across the Ku band (12.4 - 18 GHz) that has a waveguide output flange (WR-62). I am "gently re-purposing" it to be driven at a lower frequency (...
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1answer
54 views
Rectangular Waveguide H-Plane Step Discontinuity - Equivalent Reactance for Change in Height
I have been reading Pozar's Microwave Engineering, and in Section 4.6, he goes through the analysis to determine the reactance of a discontinuity between two coupled waveguides. In that chapter, he ...
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56 views
Phase and group velocity of wave
When an electromagnetic wave enter the waveguide, what is the change in the phase and group velocity that happen in waveguide?
Does wavelength or frequency of wave change when it enter the wave guide?...
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83 views
Analysis of transmission lines and waveguides
While reading the transmission lines in electromagnetic field theory , I observed that while analyzing different transmission lines like co-axial cable, and two wire lines, we are using the electric ...
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1answer
29 views
Antenna CPW internal layer
I see on the internet showing CPW( coplanar waveguide) always placed on TOP layer with ground underneath. This is what I usually do.
Is it possible to place a CPW in an internal layer? if so what ...
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92 views
RF Moding in coaxial structures
If I have a coax structure that is three sections. The mid-section has a cutoff frequency of 20 GHz and is .10” long, the two sections on the ends have a cutoff frequency of 80 GHz and each is .200” ...
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47 views
Scattering parameters of a phase shifter
I connected a phase shifter to a VNA and measured S11 and S21. Upon setting the angle (phase) to a 100 degrees and measuring the phase of S11 I obtained the following graph, whereas theoretically S11=...
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75 views
What makes the band of an antenna broader than others?
Even though I'm studying waveguide slot antennas, so the examples that I'm going to give are related to this topic, my question covers a wider range of topics.
I already know about a couple of things:...
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2answers
950 views
Designing a 50Ω coplanar waveguide on 1.6mm FR4
I'm trying to design a 50Ω coplanar waveguide to connect the output of a LoRa module to a SMD metal antenna. The two images below show the top layer (red) and bottom layer (blue). Vias are green and ...
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63 views
Waveguide with 3 dielectric sections
The cross sectional dimensions of the rectangular waveguide in the figure are
\$a=50 mm, b=25 mm\$. The waveguide consists of 3 sections filled with dielectric materials such that the relative ...
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1answer
309 views
Waveguides question
A rectangular waveguide with dimensions \$a=10cm, b=6cm\$ is filled with dielectric material with an unknown relative coefficient \$\epsilon_r\$. The guide is terminated by an unknown load. It is ...
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288 views
What are the waveguide modes of twisted pairs as discussed here?
From the recent Lightwave article ASSIA exec touts terabit-speed DSL:
In a keynote address delivered earlier this week at the G.fast Summit in Paris, Dr. John Cioffi, chairman and CEO of DSL ...
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94 views
Microwave Waveguide Power Ratio
Had a waveguide system set up similar to picture, to compare measured to calculated power ratio or path loss (differences between positions). With an SWR meter the following was recorded at various ...
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1answer
93 views
Can closed metal box work as a wave-guide for wireless transmitter?
I am using NRF24L01 and ZigBee modules for wireless communication. I kept the modules in the tapered closed aluminum cylinder for sensor data transmission. The signal was being received when the ...
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1answer
914 views
What is the simple meaning of TE10 waveguide [closed]
What does this numeral 10 represents and why do we have TE10 TE11 and then TE20. Where are the rest?
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2answers
460 views
Coplanar waveguide - Calculator question
I was looking for information on coplanar waveguides (curiosity prompted by another question here) and found this calculator.
In the description of use, it mentions that the units for the dimensions ...
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71 views
E and H field variations inside the waveguide
I wanted to know how can we visualize and draw the half cycle variations in rectangular as well as circular waveguides for TE and TM mode.
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289 views
Microwave Waveguide system tuning
I am going to built microwave system with following system configuration.
Power Circuit -> Magnetron -> Wave Guide Coupler -> Isolator -> 3 Stub Tuner -> Applicator.
Now, I want to make 3 Stub ...
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1answer
43 views
Group velocity dispersion for coupled waveguide system
I am an EE undergrad currently studying group velocity dispersion (GVD) for coupled waveguides, and am quite confused on the following question: how do you characterize group velocity dispersion for a ...
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1answer
209 views
Why is Kapton film used to hold liquid in waveguide?
I am working on a project similar to the one described in this paper
MEASUREMENT OF COMPLEX PERMITTIVITY OF LIQUIDS.
Here a Kapton film is used to hold liquids, so that they don't spill. Why is this ...
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2answers
1k views
What are the advantages of CPW over microstrip?
I have to use a coplanar waveguide (CPW) for a project which is going to characterise small amounts of tissue. I have never used CPW before.
What are the advantages of using CPW? What would be some ...
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1answer
781 views
RF cable with DC power cable?
I have a satellite communication system at office running on C-band. The C-band is downconverted to L-band and carried to the l-band modem. With this RF coaxial waveguide/cable, +12V DC power cable ...
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1answer
144 views
Coplanar waveguide vs open space?
I'm routing a U.FL connector to a cellular module (Telit GE864).
According to this calculator a 1mm track with 0.16mm gaps should provide a 52Ω impedance path to an U.FL antenna connector.
A ...
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5answers
2k views
Why are rectangular waveguides not used for inter-city transmission?
Waveguides can transmit very high powers, isolating the signal from external noises and interferences. Besides, waveguides have a very low loss. These capabilities make them an interesting candidate ...
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1answer
310 views
Impedance of waveguides shorter than 1/10 of wavelength
I read already several times that it is a common rule of thumb, that matching the impedance of a waveguide to the external network impedance is only necessary for waveguides longer than 1/10 of the ...
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2answers
280 views
Waveguides: How can you propagate at only one frequency?
In a rectangular waveguide, we know we can find cut off frequency as a function of mode and geometry.
Is there a way to design the waveguide so to ensure that we can limit the frequency of ...
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1answer
156 views
Plane wave causing TE mode in waveguide
I've been struggling with a problem given to us during a exercise-session of waveguides.
First part of the exercise was calculating the electric field inside of a waveguide in the form of 2 parallel ...
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4answers
13k views
Why is it that a TEM mode propagates in a - Two separate conductor wave guide?
Please someone explain to me in Simple English or Basic equations as to why does a Transverse Electric and Magnetic Modes(TEM) propagate on only two surface Wave ...
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2answers
1k views
Automatic impedance matching in microwave waveguides
I am trying to building a magnetron plasma using microwave magnetron.
I now need to build magnetron to antenna link using rectangular waveguide, WR-340.
I then found out that it needs to be tuned ...
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1answer
413 views
How are modes generated in a waveguide?
Its related to my previous question Modes in waveguides I have a doubt that how are different modes actually generated? I mean in Digital and Analog communication, we studied how we modulate the ...
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2answers
443 views
Why a wave does not enter a cable? Understanding TDR (Time Domain Reflectometry)
I have been doing some TDR (Time Domain Reflectometry) measures which involves sending gaussian pulses through a cable and measuring the s11 (reflection) parameter.
In this measure, I could see that ...
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2answers
1k views
Field Patterns in Waveguides
How are the field patterns for magnetic and electric field obtained using the field equations? What is the intuitive way of understanding and drawing them? I searched a lot regarding the method for ...
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1answer
611 views
Reflection coefficient VS frequency
I was trying to look for the answer of what I think it should be quite a simple question but I haven't found any nice answer (at least any that has convinced me).
Here it is:
Through a cable (...
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1answer
807 views
Modes in waveguides
What is the meaning of Modes in waveguide? With what physical property of the Electromagnetic wave does it deal with? I have just started with parallel plane waveguide and in that case the constant m- ...
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1answer
411 views
Contact pad size for microprobe coaxial to planar waveguide transition
http://www.ggb.com/t-4.html
Can someone explain what size one should choose at minimum/maximum for the pads and what role the pitch plays (besides impedance matching)? If I order a 100 micron tip ...
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1answer
937 views
Tapering of planar waveguides
Can anybody recommend some literature or explain some rules of thumb for tapering planar waveguides? As I understand correct tapering is needed for example for bended waveguides or like in the picture ...
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1answer
1k views
Differences between a planar coil and coplanar waveguide to create a local 1D AC magnetic field
Coplanar waveguides (for example picture look here) are often used in research to create a local in-plane magnetic field. Now if compared to a planar microcoil like this,
driven by a AC voltage in ...
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1answer
11k views
Connecting horn antenna to a gunn transceiver
I have a surplus Microsemi MO9072 24GHz gunn transceiver (Datasheet) and a matching MDT86552 horn antenna (Datasheet) that I'd like to use in a project. In the same package was a waveguide of some ...
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1answer
989 views
Simulation software to terminate planar waveguides by geometry and material choice?
There are a lot of electromagnetics software modeling suites out there (HFSS, CST Microwave, Sonnet some I've heard of).
I want to terminate a coplanar GS or GSG waveguide with 50 ohm. I know that ...
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0answers
305 views
Impedance calculators differ pretty much?
As you can see here to calculators I found show huge difference or didn't I set it up correctly? I didn't found hints on possible validity limits. Can someone say if one of those given out results is ...
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1answer
3k views
How to terminate a coplanar waveguide with 50 ohm load?
So I want to structure a coplanar waveguide by lithography, VNA - coaxial - picoprobe - coplanar waveguide transition to measure impedance of the waveguide. As signal and ground lines are on one ...
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2answers
4k views
Can I improve the directivity of an X-band radar module with integrated plane-patch antenna?
Lots of detail provided in case it's needed.
I'm continuing to tinker with remote proximity sensors driven by an Arduino (and eventually just an ATMEGA* chip and its safety buddies) and have a pretty ...
