What Is a Microwave Antenna?

Mal Baxter

A microwave antenna is designed to receive and transmit electromagnetic radiation with wavelengths between infrared (IR) radiation and radio waves. Microwave radiation can travel through the atmosphere or space; the antennas pick up those signals in broadband, a specified band, or single frequency. The technology comes in many sizes and shapes, linking voice and data wireless transmissions for applications such as radar, radio astronomy, and telephone networks.

One type of common microwave antenna is used in cell phones.
One type of common microwave antenna is used in cell phones.

Microwave antenna applications vary from radio, television, and data communications to radiolocation along the ultra-high frequency (UHF) and military super-high frequency (SHF) bands of the electromagnetic (EM) spectrum. As such, these antennas come in a wide range of shapes and sizes. These can include small helical antennas such as the type found on automobiles, and wireless fidelity (WiFi) antennas for computers and cell phones.

Cell towers may use different types of microwave antennas for voice and data transmissions.
Cell towers may use different types of microwave antennas for voice and data transmissions.

Others are designed in compact lozenge shapes. Larger WiFi antennas are placed on telephone poles and rooftops around cities, universities, and commercial and residential properties in order to transmit data where mobile computing is required. Parabolic dish antennas are high-gain reflectors used to transmit massive amounts of data for media transmission, radio astronomy, and radiolocation (radar).

One type of common microwave antenna is used in cell phones. This mobile communications device transmits in microwave frequencies by radiating energy in every direction. A base station receives the transmission and sends it through relays in a telecommunications network until it reaches its destination. Signals can include data that carry voice, video, and text. Weather effects can influence the performance of the signal, including all types of precipitation, atmospheric conditions, and even physical obstructions that prevent line of sight communication with relay links.

Other factors influencing the utilization of microwave technology include security and casual snooping. Another problem can be channel pollution, that is, commercial competition for limited bandwidths. Additional factors include hardware designs, range, and piggy-backing onto other parties' network subscriptions.

Whatever size or shape of microwave antenna, these powerful transmitters emit radiation in various states of intensity. This includes WiFi and Bluetooth® antennas within networked hot spots often found in public areas. For cell phones, research has shown that these transmission signals are strongest in the initial connecting process, but emit continuously while the phone is powered. Other similar radiating devices include microwave ovens and cordless telephones; these units consistently emit signals. Today's wireless inhabited area continually exposes people to a continuous low field of electromagnetic radiation, with varied degrees of potential health risk.

Learning How Microwave Antenna Works in the Real World

The microwave section of the electromagnetic spectrum exists between wavelengths of 1m - 1mm. This makes the corresponding frequency between 1 - 300 GHz. For a microwave transmitter to communicate with a receiver, the device must be capable of creating electromagnetic waves with the correct wavelength and tuned to the correct frequency. Further, the transmitter and receiver need good line of sight with no obstructions in the path. Radio interference, poor weather, precipitation and buildings are all objects that can cause poor signal quality. There are several different types of popular microwave antennas with different shapes and designs for different applications.

Cell phones use microwaves for a variety of things, leaving humans saturated in the stuff. The most-used signals on mobile devices, such as Wi-Fi, GPS, and Bluetooth all utilize microwave antennas. We are all experiencing microwave radiation contamination all the time from many of our own devices and also from the universe propagating microwaves through the planet. We don't currently have any real idea of the long-term effects of microwave signals penetrating the body.

Learning What Are Microwave Antennas Used For

Microwaves are used frequently for point-to-point communications between two parties. The small wavelength nature of microwaves allows them to be "shot like a beam" from transmitter to receiver. This allows simpler frequency usage at both ends, and much less interference from other microwave transmissions, unlike radio waves which radiate in all directions and interfere with everything.

Common Uses for Microwave Antennas

  • Media/Broadcasting/Streaming/Television
  • Radio
  • Astronomy/Radio Telescopes
  • Marine Communication/Remote Location Communication
  • Military Communication/Radar
  • Weather Radar
  • Cellular Telecommunication Relay and Transmission

5 Types of Microwave Antennas

MIMO - Multiple Inputs and Outputs

  • Mimo antennas use multiple versions of the same signal to increase accuracy and create an efficient signal. Its use in 4g and 5g telecommunication transmission is perfect for creating a stable and robust signal. It is used frequently in Wi-Fi and cellular network connections.

Parabolic Antenna

  • Parabolic antennas use their dish shape to their advantage by gathering the beam for improved accuracy and decreased noise. These can be found in grids for deep universe radio observation and even in residential settings for customers who subscribe to satellite television.

Microstrip (Patch) Antenna

  • Patch antennas, also known as microstrip antennas, are becoming very popular due to their ultra-small footprint. Highly conductive metal, such as copper, is cut incredibly thin and placed on an insulator substrate piece. Cellphone manufacturers are printing the patch antennas directly to the device's mainboard because of how small and efficient they are.

Omnidirectional Antenna

  • Omnidirectional antennas have applications that require wide dissemination of the signal in all directions. They can send the signal in all horizontal directions, covering an entire city. These are obviously best when positioned in the center of the area it should be servicing.

Horn Antenna

  • Horn antennas are similar to parabolic ones, except they have different shapes for their waveguide metal frames depending on the specific application. They are great at gathering and sending beam-like signals, and their signals tend to be very accurate and of high strength. They can be used for testing the accuracy of other antennas, and for feeding signals to larger arrays of parabolic antennas.

Learning Advantages and Disadvantages of Microwave Transmission

Advantages

The advantages of microwaves over other available forms of communication are many:

  • Available to run at high frequency
  • Low interference with other microwaves
  • Can be engineered for specific applications
  • Accurate, low noise signals
  • Very low power requirements
  • Doesn't need repeaters
  • Works in space
  • Antennas are versatile

Disadvantages

They share many of the same disadvantages as other forms of communication and a few unique ones:

  • Requires good line of sight
  • Poor omnidirectional transmitting
  • Requires engineered models to build
  • Relatively slow transmission speed
  • Weather interference
  • Atmospheric absorption
  • Reflects easily

Learning How To Align Microwave Antenna

For parabolic microwave antennas, such as satellite dishes for houses, the alignment process requires pointing the dish unit towards the equator (where the orbiting feeder satellite exists in space) and tuning the adjustments.

Other types of microwave antennas will have a similar method to set them up. They need to point directly at the transmitting signal. The better the line of sight, the better the signal will be. Poor weather and clouds can compromise a signal.

Tuning the alignment of the antenna will require first making coarse adjustments, followed by fine adjustments until the best measurable signal is achieved. Most antennas will come with pivoting, sliding and tilting frames that allow them to bolt down and still articulate certain ranges of motion. Once the tuning trim is complete, tighten the frame down. These adjustments should be done in unison with a signal measuring device in real-time.

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Discussion Comments

anon212076

The government used to think cigarettes were good for you, and put them into soldier's field rations in World War II. It took a long time to convince people that it is bad for you. I met people from China in the 1980's who smoked cigarettes constantly, and when I told them it is really bad for you, they insisted I was mistaken.

I used to work for the Navy as a civilian, and workers were still allowed to smoke in our office in 1990 when I left. So much for government concern over our health -- even when the health threats are known.

It will come to light over the next century or so exactly how bad electromagnetic radiation is for us. Back in 1983, I read newspaper articles that showed how working at microwave repeater stations was affecting people's memories. Detrimental effects are constantly popping up.

A new commission established by the EU government is recommending that wireless routers and other microwave emissions be halted in schools.

Exposure to various types of electromagnetic radiation (EMR) can cause depression, memory loss, reduced immune response, increased cancer rates, etc. There are studies supporting this. Of course there are studies disproving this, but look at who's funding the studies.

Unfortunately, one of the only growing sectors of our economy has been telecommunications; thus, it is one of the only sectors of the economy providing growing tax revenues vs. shrinking taxes. So, don't expect any governments to be quick to prove it is bad for you. They literally can't afford it.

Be safe. Err way on the side of caution.

Almata

The comment, "with varied degrees of potential health risk," makes you wonder, doesn't it. It seems that one day something is bad, and the next day it's not. Because microwaves can be harmful in varying degrees, people used to be, and sometimes still are, concerned about the use of a microwave oven.

But the microwaves don't leave the oven because the material used to make the oven keeps them inside of it. Moreover, the FDA says any leakage is not enough to be harmful. So, I guess all you have to do is figure out where the other microwaves are that are coming from other sources and duck them.

But seriously, the government regulates microwave levels to keep them safe. Additionally, microwaves, unlike radiation, are non-ionizing, meaning they are not powerful enough to ionize cells, which could alter cells and kill them off, like in cancer therapy. The microwaves bouncing around you every day won't do that.

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