Microwave engineering

Microwave engineering pertains to the study and design of microwave circuits, components, and systems. Fundamental principles are applied to analysis, design and measurement techniques in this field. The short wavelengths involved distinguish this discipline from Electronic engineering. This is because there are different interactions with circuits, transmissions and propagation characteristics at microwave frequencies.

Some theories and devices that pertain to this field are antennae, radar, transmission lines, space based systems (remote sensing), measurements, microwave radiation hazards and safety measures.

During World War II microwave engineering played a significant role in developing radar that could accurately locate enemy ships and planes with a focused beam of EM radiation. The foundations of this discipline are found in Maxwell's equations and the work of Heinrich Hertz, William Thompson's waveguide theory, J.C. Bose, the klystron from Russel and Varian Bross, as well as contributions from Perry Spencer, and others. ^[1]

The microwave domain

Microwave is a term used to identify electromagnetic waves above 10³ megahertz (1 Gigahertz) up to 300 Gigahertz because of the short physical wavelengths of these frequencies. Short wavelength energy offers distinct advantages in many applications. For instance, sufficient directivity can be obtained using relatively small antennas and low-power transmitters. These characteristics are ideal for use in both military and civilian radar and communication applications. Small antennas and other small components are made possible by microwave frequency applications. The size advantage can be considered as part of a solution to problems of space, or weight, or both. Microwave frequency usage is significant for the design of shipboard radar because it makes possible the detection of smaller targets. Microwave frequencies present special problems in transmission, generation, and circuit design that are not encountered at lower frequencies. Conventional circuit theory is based on voltages and currents while microwave theory is based on electromagnetic fields.^[2]

Apparatus and techniques may be described qualitatively as "microwave" when the wavelengths of signals are roughly the same as the dimensions of the equipment, so that lumped-element circuit theory is inaccurate. As a consequence, practical microwave technique tends to move away from the discrete resistors, capacitors, and inductors used with lower frequency radio waves. Instead, distributed circuit elements and transmission-line theory are more useful methods for design and analysis. Open-wire and coaxial transmission lines give way to waveguides and stripline, and lumped-element tuned circuits are replaced by cavity resonators or resonant lines. Effects of reflection, polarization, scattering, diffraction and atmospheric absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply at all frequencies.^[1][3]

Relevance

The microwave engineering discipline has become relevant as the microwave domain moves into the commercial sector, and no longer only applicable to 20^th and 21^st century military technologies. Inexpensive components and digital communications in the microwave domain have opened up areas pertinent to this discipline. Some of these areas are radar, satellite, wireless radio, optical communication, faster computer circuits, and collision avoidance radar.^[4]

Education

Colleges and universities offer microwave engineering.

The University of Massachusetts Amherst provides research and educational programs in microwave sensing and communications systems. Courses and project work are offered leading toward graduate degrees. Specialties include microwave and RF integrated circuit design, antenna engineering, computational electromagnetics, propagation, microwave remote sensing systems, image processing, and THz imaging.^[5][6]

Tufts University offers a Microwave and Wireless Engineering certificate program as part of its graduate studies programs. It can be applied toward a Masters degree in electrical engineering. The student must have an appropriate bachelors degree to enroll in this program.^[4]

Auburn University offers research for the microwave arena. Wireless Engineering Research and Education Center is one of three research centers. The university also offers a Bachelor of Wireless Engineering degree with a Wireless Electrical Engineering major.^[7][8][9]

Bradley University offers an undergraduate and a graduate degree in its Microwave and Wireless Engineering Program. It has an Advanced Microwave Laboratory, a Wireless Communication Laboratory and other facilities related to research. ^[10]

Societies

There are professional societies pertinent to this discipline:

The IEEE Microwave Theory and Techniques Society (MTT-S) "promotes the advancement of microwave theory and its applications...". The society also publishes peer reviewed journals, and one magazine.^[11]

Journals and other scholarly periodicals

There are peer reviewed journals and other scholarly periodicals that cover topics that pertains to microwave engineering. Some of these are IEEE Transactions on Microwave Theory and Techniques, IEEE Microwave and Wireless Components Letters, Microwave Magazine, ^[12] and IET Microwaves, Antennas & Propagation. ^[13]

See also

• Artificial dielectrics
• Microwave transmission
• Winston E. Kock

References

1. ^ ^{a b} Das, Annapurna ,; and Sisir K. Das (2000, 2008, 2009). Microwave engineering. McGraw-Hill core concepts in electrical engineering series. (1st ed.). McGraw-Hill Higher Education. ISBN 9780073529509. http://books.google.com/books?id=ZU19Uemy83YC&printsec=frontcover&dq=microwave+engineering&hl=en#v=onepage&q&f=false. 
2. ^ "Module 11 — Microwave Principles" (Free PDF download). Navy Electricity and Electronics Training Series (NEETS). United States Navy. 1998. pp. 1-1 to 1-10. http://www.phy.davidson.edu/instrumentation/Files/NEETS/Mod11%20-%20Microwave%20Principles.pdf. Retrieved 2011-09-04.  Prepared by FTCM Frank E. Sloan
   • This article includes text from an official United States Navy website. As a work of the U.S. federal government, the text is in the public domain.
3. ^ This paragraph was directly copied from the Wikipedia article entitled Microwave. (September 04, 2011). However this material is covered by the reliable source provided in this article (Das, Annapurna; and Sisir K. Das. Microwave Engineering. McGraw-Hill Higher Education).
4. ^ ^{a b} Microwave and Wireless Engineering (2011). "Certificate program" (online web page). Tufts University. http://gradstudy.tufts.edu/admissions/programs/certificates/microwavewirelesseng.htm. Retrieved 2011-09-12. 
5. ^ "Research Center & Labs" (online web page). University of Massachusetts Amherst. 2011. http://ece.umass.edu/ece/research-centers. Retrieved 18 October 2011. 
6. ^ "Graduate Degrees" (online web page). University of Massachusetts Amherst. 2011. http://ece.umass.edu/ece/graduate/future-students. Retrieved 18 October 2011. 
7. ^ Research and Outreach (2011). "Overview" (online web page). Auburn University (Alabama). http://gradstudy.tufts.edu/admissions/programs/certificates/microwavewirelesseng.htm. Retrieved 2011-09-12. 
8. ^ "Undergraduate Programs" (online web page). Auburn University (Alabama). 2011. http://www.eng.auburn.edu/elec/programs/index.html. Retrieved 2011-09-12. 
9. ^ "Wireless Engineering Program Options" (online web page). Auburn University (Alabama). 2011. http://www.eng.auburn.edu/wireless/programs/ugrad/options.html. Retrieved 2011-09-12. 
10. ^ "Microwave and Wireless Engineering Program" (online web page). Bradley University (Illinois). 2011. http://cegt201.bradley.edu/rfpage/. Retrieved 2011-09-12. 
11. ^ "About MTT-S" (Online web page). http://www.mtt.org/about-mtt.html. Retrieved 2011-09-12. 
12. ^ "MTT-S Publications" (Online web page). http://www.mtt.org/publications.html. Retrieved 2011-09-12. 
13. ^ "IET Microwaves, Antennas and Propagation" (Online web page). Institution of Engineering and Technology. http://www.ietdl.org/IET-MAP. Retrieved 2011-09-12. 

Further reading

• Dong, Junwei (2009). Microwave Lens Designs : Optimization, Fast simulation algorithms, and 360-degree scanning techniques (PhD thesis). Virginia Polytechnic Institute and State University. OCLC 469368809. Docket etd-09242009-195704. http://scholar.lib.vt.edu/theses/available/etd-09242009-195704/unrestricted/Dong_J_D_2009.pdf. Retrieved September 01, 2011.