EEM226 Elektromanyetik Dalga Teorisi I: Elektromanyetik Dalga Teorisine Giriş (S. Gökhun Tanyer)

Prof. S. Gökhun Tanyer'in Başkent Üniversitesi EEM226 dersi için hazırladığı 49 sayfalık “Introduction to the Course – 0C” sunumunun metin dökümüdür. PDF 17 Şubat 2015 tarihlidir; belgede dersin İngilizce adı Electromagnetic Wave Theory I olarak geçer. Orijinal PDF yazının sonunda indirilebilir.

Not: Kaynak sayfası, Cheng kitapları ve Course Outline kaynaklarından yararlanıldığını; belgenin Başkent Üniversitesi öğrencileri için hazırlandığını ve kopyalama/internette yayımlamanın belge sahibinin iznine bağlı olduğunu belirtmektedir. Bu uyarı kaynakta aynen bulunmaktadır.

Bu içerik üçüncü taraf bir kaynağa aittir; arşiv ve nostalji amacıyla kaynak belirtilerek paylaşılmıştır. Hak sahibinin talebi hâlinde kaldırılır.

Why do we have this course?

Electromagnetic Wave Theory I builds on vector algebra, line, surface and volume integrals, and vector operators. It connects static electric and magnetic fields to time-varying fields, wave dynamics, standing waves and light.

Related subjects listed in the presentation are Electromagnetic Wave Theory II, Antenna Theory and Electromagnetic Propagation, Microwave Theory and Applications, Radar Systems and Optical Wave Theory.

Three introductory questions

1. Why is the sky blue, and why is the sunset red? Explain Rayleigh scattering.
2. How do you define interference? Explain the particle and wave properties of light.
3. What is polarization? Explain its role in polarizing glasses.

These are research questions in the source; the slides do not present a complete written solution.

Dersin mühendislikteki yeri

Elektrik ve manyetik alanlar, elektrikli ve elektronik cihazların çalışma ilkelerini anlamak için gereklidir. Uzaktan algılama, elektrik motorları, iletim hatları, dalga kılavuzları, antenler, anten dizileri ve radar sistemleri uygulama örnekleridir.

Alanlar üç boyutlu uzayda tanımlanır ve zamanla değişebilir. Bu yüzden koordinat sistemleri, skaler ve vektör tanımları, gradyant, diverjans ve bukle araçları birlikte kullanılır.

History of electromagnetics

The historical sequence includes Coulomb, Gauss, Laplace, Poisson, Ohm, Joule, Biot, Savart, Ampère, Helmholtz, Faraday and Maxwell. The Turkish introduction links Ørsted's current and compass experiment, Faraday's induction work, and Maxwell's mathematical formulation.

Not: Faraday'ın portresinde “1891, 1867” yazılmıştır; doğum yılı 1791 olmalıdır. Kaynaktaki tarih hatası burada belirtilmiştir.

Light and its speed

The presentation compares early ideas about vision and light, followed by measurements associated with Rømer, Huygens, Fizeau and Foucault. It connects Maxwell's equations with the electromagnetic nature of light.

A historical measurement is quoted as c=299792456,2±1,1 m/s. The later adopted exact value is c=299792458 m/s. The metre is described using the distance travelled by light in vacuum in 1/299792458 second.

The 2011 OPERA neutrino result is described in the source as a mistaken faster-than-light observation, rather than evidence against the usual light-speed limit.

Electromagnetic spectrum

The spectrum diagrams compare radio, microwave, infrared, visible, ultraviolet, X-ray and gamma-ray regions. Frequency increases as wavelength decreases. A microwave conversion shown in the slides is:

λ[mm] = 300/f[GHz].

The diagrams credit S.-O. Park, R. M. O'Donnell, Kevin Chen, and Kämpfer/Murk. The spectrum is also compared with object sizes, atmospheric transmission and thermal emission.

Atmospheric transmission and absorption in water

Transmission depends on wavelength and medium. Atmospheric windows and absorption regions help explain the choice of operating bands. The water examples show that different visible wavelengths are attenuated differently, changing the colours observed with depth.

Sources printed on the water slides include John Easley, SEOS and DeepOcean. The graphs are teaching illustrations in the source; they are not a single universal attenuation law for every type of water.

RF and optics analogy

Incident light at a boundary can produce reflected and transmitted waves. The presentation compares this with radio-frequency energy at a transmission-line junction. It also gives examples of terahertz imaging, metamaterials, Earth-observing satellites and microwave radiation in everyday environments.

Antennas and later courses

The antenna examples include dipole, circular loop, rectangular loop and helix antennas; television and radio antennas; GSM base stations; rectangular and circular microstrip antennas; reflector arrays; Yagi–Uda arrays; and aperture antennas.

The final slides connect these examples to microwave theory, radar systems and optical wave theory. Their purpose is to show where the course's field and wave concepts will be used.