Lecture -- Wave Parameters
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- Опубликовано: 23 май 2024
- This video begins to introduce the parameters that describe the properties and behavior of waves. By comparing the electromagnetic wave equation to the historical wave equation, the speed of an electromagnetic wave is determined. From this the refractive index is derived, which leads to the discussion of how speed, frequency, and wavelength of a wave are related. Some discussion is given about the wave number and wave vector and they wavelength and refractive index. The video ends with a discussion about impedance of a medium.
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#electromagnetics #optics #maxwells #electric #magnetic #waves #TEM #polarization #amplitude #phase #helmholtz #refractiveindex #refraction #waveequation #speed #frequency #wavelength #impedance #wavenumber #wavevector #exponential #graphics #visualization #empossible #rumpf 
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I wrote over 20 papers on metamaterials 18 years ago, and then switched my career to teaching maths and engineering to teenagers. I am still very interested in the research of metamaterials and after following your lectures in the past six years you have helped me make sense of the theoretical understanding of some crucial parameters. I wish I had those understanding 18 years ago when I had more time to consolidate the knowledge and practise it. Please continue to share your lessons or lectures, because it is making an impact for people like me who are still trying to understand metamaterials properties. Your delivery approach is very unique and accessible for beginner level into the subject, and not limited to MIT boffins.
Thank you! You have made my day!!! My metamaterials information is quite old now. I have learned more and better graphics skills. I need to redo and improve those materials! I am curious what you researched.
@@empossible1577 I researched on reduced sized unit cell elements. I thought by increasing capacitance and inductance of a single unit cell would reduce the resonance frequency or band gap frequency, so I applied Hilbert curves and convoluted elements while still keeping the vias. I then assisted in the practical development of wire medium.
@@dukiesengineering At that scale, coupling short circuits the elements. I think that is why ideas like fractal antennas fall short of what we think should be possible. We are working on using the dielectric to effectively stretch space (think transformation optics) to reduce the mutual coupling in fractal-ish designs. So far, the idea has failed miserably. LOL
@@empossible1577 What frequency are you testing your ideas? While I love to endure THz and upwards as it seems is a trendy thing to do, I simply preferred 60GHz or lower to avoid plasmonic territories which is an area I don't have the capacity for. Also, imaging me going to my school headteacher asking for a funding for a 2nd hand THz VNA of USD 90000 for our 16 to 18 years old school projects, he must think I am having a laugh. As I don't have an anechoic chamber, much of my work now is mainly CST simulation and S11 measurement up to 6GHz. I get the teenage students to model antenna and unit cell on CST. They measure the bandgap frequency using two monopole antenna edge to edge of a 2D metasurface, I prefer the term high impedance surfaces back in Sievenpiper's days. I used to use FR4, now I get my students to 3D print the substrate using PLA filament of epsilon 2.2 to 2.9 depending the infill settings. I am having fun to try and develop metamaterials using standard classroom machines as I don't have hundreds of thousands of dollars funding, instead I get USD3000 school budget to spend on teaching consumables. I am working on developing a small size near field to far field computer controlled system using some left over stepping motors from an obsolete 3D printer. Do you have a working measurement setup to detect band gap of 2D or 3D metamaterial?
Fantastic stuff!
Brilliant. I have just had a penny-dropping monent watching this.
Thank you. What is a penny-dropping moment? I've never hear that expression.
@@empossible1577 If the penny drops, you suddenly understand something:
@@williamnelson4968 Thank you!
Thank you so much
It is a nice job you have done here, but you have to modify the orientation of H (180 degrees) in your last animation, because ExH is in the k direction (Right hand rule)
Thank you for pointing this out! Here I incorporated a phase shift, but too dramatic of one and it mostly looks 180 degrees away from where it should be. I noted this and will revise next time I edit this video.