Microwave Definition and 346 Threads

Does the operation of a cylindrical microwave cavity resonator as described here, https://en.wikipedia.org/wiki/Microwave_cavity, depend on the speed of light being isotropic along the cylinder axis?

I'm new to PF, I have an engineering background, but am trying to understand how microwave plasmas are generated. I'm trying to work out if a tuned microwave waveguide can create a plasma in a specific point in the waveguide say over 30 seconds as the microwave energy heats up the waveguide thus...

Some fireworks in our microwave from peeling paint got me thinking... If you place a fork inside, arcs will form between the tines. Why? Presumably the EM field is inducing different potentials on each tine, and the pointiness concentrates the field enough to exceed the breakdown voltage there...

I am looking for calculating color temperature in the IR/Microwave scale frequencies, for room temperature, 273K, 263K, 253K, all google is showing is about visible light and about display systems.

Glass allows visible light to pass through I would like to find a list of materials that allows lights of different EM spectrum to pass through, not just the above, Searched throughout google, couldn't find any!.

So I printed this antenna with some conductive filament , however the microwaves seems to be going between the layers of the plastic. I surrounded it with Aluminum and still leaking, what can I do to fix it? Can conductive silver paint work?

I'm currently working on a novel RF and MW sensor and I wanted to know whether there is a paper that shows the current very best receiver sensitivity for a range of wavelengths in the RF-MW range in dBm preferably so I can directly compare to my device.

we planning to heat water directly using microwave for industrial purpose. we need only 33deg Celsius for that I need this.

Hello, This is a question that is haunting me when I saw small red ants go in and come out alive of microwave oven that was. Long story short, I was warming some food item in the microwave oven. When I put the container in the microwave oven, I missed to notice that there were few live...

Before we start, this transformer will be used in a closed shop, on a clear bench and via a remote switch. I will be in full view of the setup. I hope to try some Lichtenberg patterns. I see that the secondary, c. 2000V winding is referenced to the transformer core. What is the purpose of...

Since the wavelength microwaves used in microwave ovens have a wavelength of 12cm, why are the holes in the grid behind the glass so small? If they were 12cm would the microwaves still stay confined? If the small holes are only to "play it safe" that seems irrelevant since microwave has a...

I've noticed that when I put a prefab meal in the microwave, the parts that are frozen over just don't defrost any time soon, even though the rest of the meal gets really hot. The reason is that the ice structure doesn't allow the polar water molecules to vibrate. My question: what can we do so...

Homework Statement I am working on a lab report, and I am a bit stumped at these questions: How does reflection affect the intensity of the microwave? Is all the energy of the wave striking the Reflector reflected? Does the intensity of the reflected signal vary with the angle of incidence...

Hello! I am reading some basic stuff in cosmology and I am a bit confused by the microwave background. As far as I understand, it is the radiation produced at the beginning of the universe, when the matter density was not that high so the photon can escape and travel freely. So the microwave...

Hi ! I am actually seeking help regarding working principle of microwave based photonic filters from basics, I have tried a lot I did find allot of material but non of them were describing the basic working principle. Helping in this regard will be highly appreciable. Regards

How useful are non-navigational radio beacons (i.e., for determining current propagation conditions and testing) nowadays, whether microwave X band, HF, ELF, sub-mm wave, etc., considering the advent of computerized propagation modeling? Is the scarcity of non-amateur radio beacons a result of...

If the cosmic microwave background occurred at the moment that electrons and protons joined together and photons were now free to travel across the universe, then why haven't those photons already passed it. I'm having a hard time understanding why we can see the CMB forever if it was simply a...

I am looking for what the high end radar receivers can achieve in terms of sensitivity? I have had trouble finding examples online, I have seen -100 to -103dBm as typical sensitivities, but I'm looking for the cutting edge stuff. I've also seen the GPS satellites also have a sensitivity of...

Hi, I am carrying out some tests using the laser image transfer method, where the image of a circuit is put on a PCB as an acid resist, so leaving the circuit in copper. My thread PCB by Laser transfer. My method is a 'sandwich' of two stiff plates app 110x160mm bolted at the edges...

Hi! Completely forgot about this great forum! I'm designing an electron spin resonance /electron paramagnetic resonance spectrometer, as an easier vacation from my diy NMR - while still utilizing much of the same setup. Issue is; I have an X-band (~12GHz) waveguide cavity in a magnet, and I...

Can someone enumerate the equipment needed in a microwave transmitter control room? i already searched the net and i somehow don’t understand anything haha. also can you please explain what each equipment does? thank you :)

Consider the microwave cavity used in a particle accelerator to accelerate particle bunches. Before a bunch of particles enters the microwave cavity can we, if only in principle, quantum mechanically describe the state of the microwave cavity as a proper sum of microwave photon number states...

Hi everyone, I am trying to understand that why do we use open circuit terminator for wave guides or any RF element such as coupler and etc. I know if we just leave it open, it does not work as open circuit. But why?

A problem I encounter when microwaving food is that the centre is no penetrated by the microwaves so remains cool and I have to wait for the heat to be conducted through which takes a long time and undermines one of the advantages of microwaving which is the speed of the process. Would it make...

Are microwave susceptors attenuated in viscoelastic mediums ? I am experimenting with some widely known microwave susceptors like iron oxide and silicon carbide (materials that normally convert RF to heat quite effectively). In ceramic formulations they perform great, as expected. When...

I am experimenting with some widely known microwave susceptors like iron oxide and silicon carbide (materials that normally convert RF to heat quite effectively). In ceramic formulations they perform great, as expected. When formulated in silicone rubber, they do not perform when subjected to...

There are many webpage about dielectric antenna For instance, https://en.wikipedia.org/wiki/Dielectric_resonator_antenna But I cannot figure out where does the energy feed-in or take-out from the antenna?

Hi guys, If i put mobile phone into micro oven, Is this prevent mobile signal

If we were to take a microwave picture of a region of space said to have a black hole, would we be able to spot the black hole? Would we see a cold spot surrounded by a more hotter background?

Homework Statement Two single frequency coherent microwave beams are directed from the same point towards a concave mirror. One beam is incident parallel to the principal axis of the mirror, 0.06m from the axis. The other beam passes through the focal point before striking the mirror. The...

I am interested in building a microwave powered toy helicopter purely for the fun of it. As we have discovered in our initial research, it isn't possible to direct the microwaves from a microwave oven magnetron too far. I know that those microwaves are of a similar wavelength (or is it?) What...

Would it be a drop in power as the square of the distance in a directed microwave beam? Thanks!

Hi, according to http://www1.lsbu.ac.uk/water/microwave_water.html and other sources the penetration depth of a microwave wave is proportional to the square root of the dielectric constant divided by the dielectric loss. For me it makes sense that as the dielectric loss increases more energy is...

and if so what is it's orientation

Hi there, We can't use Infrared rays outside for data communication of our home as sun light also contain infrared rays which possible will interfere with it.That's what i read in Data communication book. My Question is , Does sun rays also contain radio wave, microwave ? if yes, then why can't...

Hi there, Wifi uses either 2.5 GHZ band or 5 Ghz band and these bands lie in Microwave in EM spectrum. As i read in books, Microwaves are propagated using line of sight (LOS) technique, so sending and receiving antennas should need to be aligned accordingly. But WiFi signals are broadcasted...

I recently talked to a friend of mine about microwaves. Specifically that (to my knowlege) the microwave radiation is primarily absorbed by a rotational degree of freedom of water molecules. Which got me thinking. 1.First of all what would happen if you put a extremely cold ice cube ( with no...

When a "layman" hears of the cosmic microwave background, and this layman also has a passing knowledge of big bang theory, it can be difficult for said layman to wrap his head around what the CMB really is. That layman might ask, wouldn't this primordial radiation have "passed" us by now, and...

Awhile ago, I was considering what sort of dangers a spacecraft moving at relativistic speeds would face in interstellar space. Aside from the obvious pieces of space dust being relativistic bullets in the ship's frame of reference, the cosmic microwave background (CMB) would become a big...

I understand in an electric circuit electrons in metallic materials move around by being directed by potential differences (fields!) I guess in a microwave circuit photons propagate as waves and are directed around and manipulated throughout the circuit by its geometry? Or have I got this...

Hi This question may have already been answered elsewhere. If so please accept my apologies in advance. I am confused! The textbok(s) I am reading describe a whole bunch of different causes for there being temperature fluctuations in the CBM, so I am confused about which one(s) of these...

I live in an rv. My power comes from solar and ocassional boost from my generator. I have 3600wh in battery power. But i know its really bad for my batteries to draw lot of power fast. So i would like to create a capacitor bank that would stay charged. Ive done some calculations but not...

Hello everyone I've a question about the cosmic microwave background which my nephew asked me a couple of days ago. How much energy hits the Earth each year from the CMB? I'm assuming here that it is measurable in this way, but apologies if not. Thanks in advance for your help. Chris

Microwave oven operates at 2.4 GHz. Consider the situation of making tea or coffee in Microwave where water is heated to 100C to boil. Looking at Planck's law / Wien's law, 100C (373K) corresponds to a peak wavelength of 7.8nm or 38.6THz which is in Mid Infrared. Effectively materials...

Hello, I am taking some microwave engineering courses and was trying to explain the concept of reflection coefficients to my friend, but he asked me a question I am unable to answer... So we know that given a transmission line with characteristic impedance Z_0 terminated with a load impedance...

Hi pf, Please could someone provide an explanation of why the relationship between the wavelength and size of the gap is the significant factor for determining whether or not it blocks radiation in particular reference to the mesh on the door of a microwave oven. It seems very simple when a...

Homework Statement A microwave oven operates by injecting electromagnetic waves with a frequency of 2.45 GHz into the cavity formed by the conducting metal shields on each face of the oven box. Explain, with the aid of sketches and simple calculations, why it is generally necessary to rotate...

Hello, first of all, I understand, how microwave tube works but I'm interesting in how exactly the microwave heat up a things? What's the matter inside. I have heard about increasing energy of molecules of water by polarization them by micro-wave. But I have got a plate which is not from...

Does the frequency of the main affect the performance of a microwave oven? Having moved from Europe 50 Hz to the Philippines 60 Hz I can not operate my microwave oven! Is that the reason? How to remediate? Best regards.

Popcorn aside, whenever I put something in the microwave for only a few seconds longer than I probably should have, it pops. I just watched a rib-bone go flying out of its slab, meat spewing everywhere. Is heat responsible for this action?