Tagged Questions

Microwaves are radio waves with a frequency from 300MHz to 300GHz which corresponds to a wavelength of one meter down to one millimeter. Often in RF engineering however it is used to refer to a narrower region such as 1 to 100GHz.

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28 views

Microwave communication systems / data transfer rate vs data transfer speed

I'm researching about microwave communication systems, and I have to distinguish the difference between data transfer rate vs data transfer speed. I comment it will be something like you have a ...
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5answers
4k views

Why do microwave ovens, with metal walls, not blow up?

Why does a microwave oven with metal (?) walls work fine, but if I (theoretically) put a metal spoon in it, "bad things" may happen? Maybe these internal walls are not conductive?
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2answers
62 views

What is actually transformed in quarter wave transformer?

I'm reviewing some stuff on quarter wave transformer for a transmission line but since I have not had any experienced in handling these type of stuff, I am struggling to understand this concept ...
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1answer
68 views

Estimating Path Loss from Measured 2.4Ghz/Wlan Signal Strength to get Distance

I want to estimate distances between Wlan Routers based on the RSS (received signal strength) indoors. Im fully aware that I only will get rough estimates. For that I studied some radio propagation ...
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1answer
101 views

What are the bare minimum parts needed to operate a magnetron?

I recently took apart a microwave, and I managed to get a magnetron out of it, as well as a transformer that appears to be the power source for the magnetron, but looks a little small for the ...
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2answers
84 views

How Reflex Klystron works

I have a doubt on how exactly a reflex klystron works(as an RF source). In wikipedia it says that, The electrons are fired into one end of the tube by an electron gun. After passing through the ...
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2answers
346 views

Wavelengths blocked by a certain metal mesh

Introduction: I've heard about a theory, according to which you can check if there is any leakage in your microwave oven by putting your mobile phone inside and call it. However, I gave it a try and ...
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1answer
75 views

Why does the speed of the Electromagnetic wave in the material depend on the frequency of the wave where as they are constant in vacuum (freespace)?

I am confused on why would the propagation speed of any EM waves at ANY frequency is constant in the free space (vacuum) but they seem to disperse in any other materials as the propagation speed of EM ...
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0answers
36 views

Microwave Oscillator: Both Ports Unstable?

I'm just wondering, for microwave oscillators, I think both ports need to be in the transistor's unstable region. What would happen if just one port were in the unstable region and the other in the ...
2
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1answer
171 views

What does this capacitor do? (Microwave biasing circuit)

I'm wondering what \$C_B\$ attached to the bottom of \$R_{C2}\$ does. This is a screenshot from a textbook called RF Circuit Design: Theory and Applications by R. Ludwig And P. Bretchko. Looking at ...
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0answers
87 views

How to calculate Input backoff per carrier of a satellite

I was trying to calculate the sizing of SSPA in my satcom network where input backoff per carrier is required to calculate Power flux density. My current network configuration in C band is Total ...
2
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2answers
186 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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0answers
28 views

Microstrip lines- 50 ohm line for designing filter at 3.6 GHz [duplicate]

I have a question regarding microstrip lines... why do we use 50 ohm line as a standard?? please answer and attach necessary links. Thanks
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1answer
44 views

RF Ground (Reflections?)

I'm trying to understand how someone can ground an RF signal (especially relating to microstrip lines). I think I'm missing something... Since the impedance of ground is supposed to be \$0\Omega\$, ...
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vote
1answer
217 views

How to model transistor ATF 53189 in QUCS?

In my internship I have to create an amplifier with low noise, high impedance and that works in the 100 to 400MHz band. While searching for a transistor, I found the ATF 53189 (datasheet), which ...
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2answers
242 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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0answers
28 views

Hacked microwave transformers over-heating [duplicate]

I have a question regarding the excessive heat after hacking a microwave transformer. I have read and seen various items on hacking these old transformers. I needed a transformer for 2 x 15 volt at 15 ...
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0answers
104 views

Microwave damage from insulated arcing [closed]

I'm making a microwave powered aluminium smelter and I'm wondering about the safety of putting metal in a microwave. By safety, I mean risk of fire and damage to the magnetron: molten metal is the ...
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2answers
130 views

Industry standard measure for coaxial cable stiffness?

Is there an industry standard measure for coaxial cable stiffness? By stiffness I mean the spring force experienced when bending or deforming the cable. In my search for a highly flexible lab test ...
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1answer
130 views

DIY Ultra High Frequency

The book Crystal Sets to Sideband has discouraged frequencies above the low VHF band due to all of the problems with wires acting as inductors and difficulty on a stable Variable frequency Oscillator. ...
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0answers
60 views

How to calculate probability of a cellular device being able to connect to a given cell site

How would one calculate the probability that a device would connect to a given cell site (assuming the device has more than one cell site in range)? I know there are a lot of factors, but what are ...
4
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1answer
207 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 ...
2
votes
1answer
2k views

How do IMPATT and TRAPATT diodes work?

I was reading some text on microwave devices when i came across these devices.The explanation in the book was very convoluted and difficult to understand. Could some one please explain to me Basic ...
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1answer
451 views

Building a cheap and stable microwave network analyser or oscillator (2-5GHz)

I am interested in measuring the changing dielectric constant of a liquid as it undergoes a process. My background research of scientific articles shows that the 2-5GHz range provides the best ...
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1answer
507 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 ...
2
votes
1answer
3k 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
925 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 ...
5
votes
2answers
386 views

24GHz Radar : IF amplification and strange mixer output

I am currently working on a project where I have to study a microwave Doppler Radar. Here are some details so that you can better understand it : a local oscillator (LO) at 24GHz is linked to an ...
0
votes
1answer
55 views

GPS error reasons and maximising errors

I noticed that when using gps in mobile phone, I am positioned away from a wall if I stay very close to it. For example on a street with buildings on both sides, I usually get my location fix on the ...
8
votes
2answers
1k 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 ...