Questions tagged [microwave]
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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Why does 1/4 wavelength have a ground plane and 1/2 wavelength needs none?
Why does 1/4 wavelength have to have a ground plane and 1/2 doesn't?
I know that an antenna that has half a wavelength does not need the ground plane (example a dipole antenna) and when using a ...
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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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Is a microwave's output power proportional to the mass of its contents?
My friend and I are having a heated debate.
On the one hand, he thinks that a microwave oven that is empty, consumes almost no power (not considering lights, lcd, etc). He says that once you put an ...
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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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Why is a coaxial cable unbalanced?
Let's consider a coaxial cable which supplies a dipole antenna. My reference for all my statements is here.
My reference says:
Note that the current along a transmission line should be of equal ...
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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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Magnetron Working Principle
I was reading this simple description of magnetron working principle.
Can you explain me why when electrons go near the cavities, they start to resonate at microwave frequency? I do not see the link ...
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Why do we need a waveguide in a microwave oven?
Why do we need a waveguide to move microwave power from the magnetron to the microwave cavity?
Can't we just push magnetron antenna into the cavity?
Why does it have to go through a waveguide?
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What causes loss of power over lifetime of a magnetron?
The power of a magnetron declines over time\$^1\$. While not noticable for most consumer applications (A 2000-hour lifetime would last over 20 years if the device is used only 15 minutes a day), this ...
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90° Bend: Mitered vs Curved
On RF PCBs to bend a trace 90° you have many choices but among them Curved and Mitered bend considered as a good choice from performance POV (Both shown below).
For many years I thought that if you ...
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Why do we need to use transmission line theory?
I just started to learn transmission line theory. I'm still confused about a lot of things.
Every source says that we need to use transmission line theory when the length of the wire is 1/4 or longer ...
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Voltage on a Transmission Line with Ideal Conductors
Let's consider a transmission line with Perfect Electric Conductors.
We know that if an external AC source is applied, we get a voltage waveform between the conductors which is function of the ...
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Reference node in a transmission line
in "Lessons in Electric Circuits", VOL III, ChPT 14, there is a SPICE simulation of this transmission line:
The author writes:
Running this simulation and plotting the source impedance ...
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Reflection coefficient in a microwave amplifier
I have a question about the reflection coefficient in a microwave amplifier (two-port network), what is it and what is it based on?
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Determining required signal SNR (beat signal from FMCW RADAR)
I'm trying to determine the SNR required for signal outcoming from FMCW Radar.
This is the chain: signal will created by "24 GHz VCO and PGA with 2-Channel PA Output" by triangle shape frequency ...
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Self Resonant Frequency VS Package Size for capacitor
In general belief, smaller capacitors have better charactristic(more capacitive behaviour) in high frequency than bulky capacitors.
On contrary in one of my RF project (8.5GHz - 9.5GHz) when checking ...
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Are there specific microwave antennas for digital and analog signal transmission?
I'm supposed to do a class report on microware antennas. The report said we have to present 1 microwave antenna that sends digital signal and another that sends analog signals.
Do you know such ...
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Phase of Scattering Parameters
I do not understand the meaning of the phase of scattering parameters.
Let's consider for instance a two port network, and let's focus on S21.
I know that its absolute value represents a ratio ...
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Radio signal flows through glass
With these antennas; how does the signal flow through the glass?
Is it also possible across other bands; like 2.4GHz Wi-Fi signals?
Specifically tuned for the 4G NextG / 3G spectrum for optimum ...
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rectenna, diode selection
Diode problem
Used 1N4148 in combination with 100 microfarad cap, circuit gave output 14.5V and 45uA on 200 Ohms load.
But, when I use 1N4007 or FR207, they do not work, nothing on multimeter.
Can ...
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Is it safe to touch 8 volts?
Let me say first that i'm a noob in electricity.
I measured the voltage from my diy microwave-transformer-welder and it was 8.
I have no idea how much amps run through it but the fact that it creates ...
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