Microwave engineering

Key takeaways

Microwave engineering belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Microwave engineering to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Microwave engineering from memory before moving on to harder problems.

Reference excerpt

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 antennas, 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 Thomson's waveguide theory, J.C. Bose, the klystron from Russel and Varian Bross, as well as contributions from Perry Spencer, and others.

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. 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 the lumped-element model 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, the distributed-element model 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.

Relevance The microwave engineering discipline has become relevant as the microwave domain moves into the commercial sector, and no longer only applicable to 20th and 21st 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.

Education The University of Massachusetts Amherst provides research and educational programs in microwave remote sensing, antenna design 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, radiowave propagation, radar and remote sensing systems, image processing, and THz imaging. Tufts University offers a Microwave and Wireless Engineering certificate program as part of its graduate studies programs. It can be applied toward a master's degree in electrical engineering. The student must have an appropriate bachelor's degree to enroll in this program. 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. 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.

Societies 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.

Journals and other scholarly periodicals There are peer reviewed journals and other scholarly periodicals that cover topics that pertains to microwave engineering: IEEE Transactions on Microwave Theory and Techniques, IEEE Microwave and Wireless Components Letters, Microwave Magazine, IET Microwaves, Antennas & Propagation, and Microwave Journal.

See also Artificial dielectrics Microwave imaging Microwave transmission Radio-frequency engineering RF microwave CAE CAD Winston E. Kock

References

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. hdl:10919/29081. OCLC 469368809. Docket etd-09242009-195704. Retrieved September 26, 2020.

Worked examples

Example 1 — a first encounter with Microwave engineering

Start with the simplest possible case. Write down what Microwave engineering claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Microwave engineering before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Microwave engineering ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Microwave engineering

In research: Microwave engineering appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Microwave engineering in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Microwave engineering is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electrical engineering, Microwave technology, so understanding it makes those chapters shorter.
In everyday life: Look for Microwave engineering outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Microwave engineering in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Microwave engineering means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Microwave engineering out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Microwave engineering in simple terms?

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.

Why does Microwave engineering matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Microwave engineering?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Microwave engineering.