Microwave Engineering: 5 Important Factors Related To It

Points of Discussion

• Introduction to Microwave Engineering
• A brief history of Microwave Engineering
• Properties of Microwave Engineering
• Advantages and Disadvantages of Microwave Engineering
• Applications of Microwave Engineering
• Frequently asked questions on Microwave Engineering.

Introduction to Microwave Engineering

The microwave frequency range is typically 100 Mega Hertz to 1000 Giga Hertz. The range covers not only the microwave domain but also the radio frequency domain. Typical microwave domain has a frequency range of 3 MHz to 300 GHz. The corresponded electrical wavelength lies between 10 cm to 1mm. Signals having millimetre wavelengths are frequently referred to as millimetre waves. Because of the high-frequency range, typical circuit theory problems cannot solve the microwave engineering problems.

Microwave components generally act as distributed elements. The phenomena occur when the current and voltage phase varies. At lower frequencies, the wavelength gets larger. That is why there are insignificant phase changes across the dimension of the device.

Maxwell’s Theorems are one of the most used theorems in this domain.

A brief history of Microwave Engineering

Microwave engineering is one of the young and prosperous fields of engineering. The development started almost 50 years ago.The progress in this digital era in various fields is helping the microwave and RF domain to be live.

In the year 1873, James Clerk Maxwell came up with the fundamentals of Electromagnetic Theory. In the United States, a unique laboratory named as – Radiation Laboratory, was set up at the Massachusetts Institute of Technology to study, research and develop the Radar Theory. Various renowned scientists including – H. A. Bethe, R. H. Dicke, I. I. Rabi, J. S. Schwinger and several prominent scientists were there for the development in the field of RF and Microwave at that time.

Communication technologies using microwave systems started developing soon after the invention of Radar. The wide bandwidths, line-of-sight propagation of microwave technologies have proved to be necessary for both terrestrial and satellite communications. Nowadays the researches are going on the development of economic miniaturized microwave components.

Properties of Microwaves

Microwave Engineering deals with microwave signals. Let’s analyse some of the characteristics of microwave domain. 

1. Microwave signals have shorter wavelengths.
2. The ionosphere cannot reflect the microwave.
3. Microwave signals get reflected by the conducting surfaces.
4. Microwave signals get attenuated easily within shorter distances.
5. A thin layer of cable is enough for transmission of microwave signals.

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Advantages and Disadvantages of Microwave Engineering

Microwave engineering comes up with both its advantages and disadvantages. They are discussed in the later sections.

Advantages of Microwave Engineering

Microwaves have several advantages over any other domains. Let us discuss some of them.

1. Microwave has a broader bandwidth. Thus, more data can be transmitted. For this advantage, microwave signals are used in point-to-point communications.
2. Microwave antennas have higher gain.
3. Size of the antenna gets reduced as the frequencies are higher and the wavelength is shorter.
4. As microwave lie in HF to VHF, very small amount of power is consumed.
5. Microwave signals allow having an effective reflection area for the radar systems.
6. Line of sight propagation helps to reduce the effect of fading.

Disadvantages of Microwaves

Microwave engineering has some limitations also. Let us discuss some of them.

1. Microwave resources are significantly costlier. Also, installation charges are high for several types of equipment.
2. Microwave devices and systems are significant and occupy more space. However, researches are on for less space consumed devices.
3. Microwave systems some time suffers electromagnetic interference.
4. Inefficiency due to electric power may cause.

Applications of Microwave Engineering

High frequencies and shorter wavelengths of microwave systems create difficulties in circuit analysis. But these unique characteristics provide opportunities for the application of the microwave system. The below-mentioned considerations could be useful for practices.

• The antenna has a property that the antenna’s gain is proportionally related to the size of the antenna. Now, for higher operational frequency, antenna gain is comparatively larger for a given physical antenna size. It also has significant consequences when implementing a microwave system.
• More bandwidth (which is again directly related to the data rate) is gained at higher frequencies. 1% BW of 500 Mega Hertz means 5 Mega Hertz. It can give data rate around 5 Megabyte Per Second.
• Microwave has the property of line of sight, and the ionosphere cannot reflect them.
• One of the property of microwave signals, coupled with a gain of antennas, makes it unique and preferable.
• Different types of resonances like molecular, atomic and nuclear happen at microwave frequency ranges. This opens up the field for several applications in basic science, remote sensing, medical science etc.

1. The primary application of RF and Microwaves in today’s world is in wireless technologies. Technologies like – wireless communications, wireless networking, wireless security systems, radar systems, medical engineering, and remote sensing.
   • Modern day’s telephony system is evolved with the concept of cellular frequency reuse, proposed in 1947 at Bell labs. But it was practically implemented in the year 1970. In the mean-time, the demand for wireless communication increased, and miniaturization of devices was developed. Later, various communications like – 2G, 2.5G, 3G, 3.5G, 3.75G, 4G were developed using the microwave system.
2. Satellite communications are also dependent on RF and microwave technologies. Satellites have been developed for providing cellular data, videos, data connections for the whole world. Small satellite systems like GPS and DBS has been doing great.
3. Wireless local networks or WLANs connects computers within a short distance and provides high-speed networking. It is also an application of microwaves. Demand for WLANs are increasing day by day and will have high demands in future too.
4. Another application of microwaves is ultra-wideband radio. Here the broadcast signal takes a vast frequency band but has a low power level. It is a precaution for avoiding interference with other systems.
5. Radar & Military Applications: Radar systems have several applications in Defence and Militant fields, also in  profitable and research based fields. Radar is typically used to detect and mark any foreign objects inside the user’s territory in air and ground. It is also used in missile guidance and fire controls.
6. In the commercial fields, radar systems are used in ATC (air traffic control), motion detection (like- opening and closing of the door, security alarms), vehicle collision avoidance, measurement of the distance from a point.
7. Microwave radiometry is another application.

Frequently asked questions on Microwave Engineering

1. What is the frequency range for RF and microwaves?

• Answer: RF ranges from 30 MHz to 300 MHz, and Microwaves ranges from 300 MHz to 300 GHz.

2. What are the frequency bands of microwaves?

• Answer: There are 13 different frequency bands in the microwave range. The below list illustrates them.

Band Name	Range of frequency	Range of Wavelength
L Band	1 Giga Hertz – 2 Giga Hertz	15 cm to 30 cm
D Band	110 Giga Hertz– 170 Giga Hertz	1.8 mm to 2.7 mm
Ku Band	12 Giga Hertz – 18 Giga Hertz	16.7 mm to 25 mm
K Band	18 Giga Hertz – 26.5 Giga Hertz	11.3 mm to 16.7 mm
S-Band	2 Giga Hertz – 4 Giga Hertz	7.5 cm to 15 cm
Ka-Band	26.5 Giga Hertz – 40 Giga Hertz	5 mm to 11.3 mm
Q Band	33 Giga Hertz – 50 Giga Hertz	6 mm to 9 mm
C Band	4 Giga Hertz – 8 Giga Hertz	3.75 cm to 7.5 cm
U Band	40 Giga Hertz – 60 Giga Hertz	5 mm to 7.5 mm
V Band	50 Giga Hertz – 75 Giga Hertz	4 mm to 6 mm
W Band	75 Giga Hertz – 110 Giga Hertz	2.7mm to 4.0 mm
X Band	8 Giga Hertz – 12 Giga Hertz	25 cm to 37.5 cm
F Band	90 Giga Hertz – 110 Giga Hertz	2.1 mm to 3.3 mm

3. Mention some disadvantages of microwaves.

• Answer: Microwave engineering has some limitations also. Let us discuss some of them.

1. Microwave resources are significantly costlier. Also, installation charges are high for several types of equipment.
2. Microwave devices and systems are significant and occupy more space. However, researches are on for less space consumed devices.
3. Microwave systems some time suffers electromagnetic interference.
4. Inefficiency due to electric power may cause.

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