What are the most common types of communications antennas?

The most common communication antennas include dipoles, monopoles, Yagis, patches, and parabolic dishes. Each antenna type has unique uses and different advantages and disadvantages.

Nothing better reflects the progress of our civilization than the antennas that dot our countryside and our smartphones. These communications devices have profoundly impacted the way we transmit data, communicate, and broadcast. While they all serve the purpose of transmitting data, antennas are not constructed the same, and there are a vast number of different types. Let's take a look at the myriad of antenna types and their relevance to our daily lives.

What are the most common communication antennas?

The number of communication antenna types is vast, so this article will look at a few of the most common types and their uses and characteristics. In general, people interact most with dipole, monopole, Yagi, patch, and parabolic antennas. Let's start with the dipole and look at what each does and what the pros and cons are.

The following chart provides quick information about each of the antennas discussed.

What is a Dipole Antenna?

A dipole antenna is a basic antenna used to broadcast radio frequencies. A dipole antenna gets its name from the two conductors of equal length extending from either side of the antenna. A dipole is an omnidirectional antenna, which means it broadcasts frequencies in all directions simultaneously.

Dipole antennas have many uses, including television broadcasting, aircraft communications, AM/FM radio, and military applications. The biggest advantage of dipole antennas is their versatility and simplicity.

Advantages of dipole antennas include:

• Wider Bandwidth: Dipole antennas have a wider operating bandwidth compared to monopole antennas. This is very useful when broadcasting at a higher frequency range is required.
• Directivity: Bi-directional antennas provide a more focused broadcast on the axis that the directional rod extends from. This provides the ability to extend the frequency range farther than a monopole antenna.
• Balanced Configuration: Dipole antennas use a balanced configuration, with two elements of equal length. This often results in a more balanced radiation pattern and better performance in some situations.

Although dipole antennas have many advantages and are widely used, they also have some disadvantages, including:

• Limited bandwidth: Dipoles typically have a narrower bandwidth than some other antenna types. This means that they may not perform optimally over a wide range of frequencies without adjustment. They are better suited to narrow frequencies.
• Large size: As with most antennas, the size of the antenna is proportional to the frequency it captures. The lower the frequency, the larger the antenna. This is why dipole antennas are usually not suitable when size is a consideration. You may be better off using a patch antenna.

What is a Monopole Antenna?

A monopole is an antenna that consists of a single conductive element. Like a dipole, it is also omnidirectional and is used for a variety of purposes. Most often, monopole antennas are used for broadcast mobile communications, AM/FM radio, navigation systems (such as GPS), and television broadcasting.

Monopole antennas have several advantages, including:

• Compact Size: Monopole antennas are typically smaller than dipole antennas. Their compact size makes them a more practical choice when space is limited. Monopole antennas can also be extended into the sky to capture and broadcast radio signals.
• Simplicity: The simplicity of a monopole antenna makes it a low-cost and effective solution for data transmission. This is why it is often used to broadcast radio, TV, and even WiFi. In fact, when you see an old car with a radio antenna, or a home router with a big plastic stick sticking out, these are monopole antennas.

However, monopole antennas are not suitable for all situations. They also have some disadvantages:

• Ground Dependency: The biggest disadvantage of a monopole antenna is its ground dependency. Monopole antennas rely on a conductive ground plane to function properly. When there is no suitable ground plane or when the ground plane is altered, the performance of the antenna suffers.
• Efficiency issues: Monopole antennas can be affected by buildings or other nearby obstacles. The presence of obstacles can severely degrade their performance.

What is a Yagi Antenna?

The defining feature of a Yagi antenna is its multiple parallel elements. Often, you’ll see Yagi antennas on the roofs of apartment buildings, used to retrieve television broadcast signals. Unlike the two antennas discussed previously, the Yagi antenna is not an omnidirectional antenna, but a directional antenna.

What are the benefits of a Yagi antenna?

• High Gain: The best aspect of a Yagi antenna is its high gain. In terms of an antenna, "gain" refers to its ability to focus energy in a specific direction. It measures how strongly it can direct energy to its intended target, or how sensitively it can receive an intended transmission. Yagi antennas are excellent at point-to-point communications in a specific direction. This is why they are often used to receive television broadcasts.
• Great for outdoor use: Due to its rugged design, the Yagi antenna is very suitable for outdoor use. The Yagi antenna is made of anti-corrosion materials, wind pressure resistance, and waterproof to ensure good signal coverage.
• Cost-effectiveness: Yagi antennas are generally cost-effective, especially for the level of gain they offer. This makes them a practical choice in scenarios where the balance between performance and cost is critical.

Disadvantages of the Yagi antenna include:

• Fixed Directionality: The fixed directional nature of the Yagi antenna is probably one of its biggest disadvantages. This means that it must be pointed in a specific direction to work properly, and when it moves out of position, service interruptions may occur.
• Large size: Yagi antennas are fairly large, especially those broadcasting lower frequencies. This makes them difficult to maintain and complicated to install. In addition, they quickly become unsuitable for applications that require a more compact solution.

What is a patch antenna?

Patch antennas are compact traditional antennas also known as microstrip antennas. They get their name from the fact that they look like a small piece of metal. They are designed for size, weight, and aerodynamics. These directional antennas can be found in iPhones, jets, satellites, and other places where size and mass are critical.

In smartphones and other IoT devices, patch panels are great for transmitting WiFi signals. Without them, your Android or iPhone would probably stick out a monopole antenna, just like it did in the past.

What are the benefits of patch antennas?

• Lightweight: The patch panels are lightweight, which makes them suitable for applications where weight is critical. i.e. smartphones and aerospace technology.
• Convenient RFID Applications: Patch antennas are often used in Radio Frequency Identification (RFID) systems for tracking and identification purposes. Their compact size and performance characteristics make them ideal for this application.
• Low Cost: Due to its compact nature, patch panels are cost-effective to manufacture. This makes them an economical choice when budgets are limited.

What are the disadvantages of patch antennas?

• Narrow Bandwidth: Patch antennas have a narrow bandwidth, so they are less effective in situations where a wide frequency range is required.
• Sensitivity to cross-polarization: Patch antennas are sensitive to cross-polarization, meaning they may receive signals that are orthogonal to the intended polarization. This sensitivity may be limited in certain environments.
• Temperature Sensitivity: Due to the small size of the patch antenna, it can be temperature sensitive. There is a chance that it may malfunction or melt completely. This is why you should never leave your iPhone or Android phone in your car in the summer!

What is a parabolic antenna?

The most high-tech looking antenna, and what most people probably think of when they hear the word "antenna," is the parabolic dish. It's the standard dish antenna you might find on a radar system, satellite communications, or even DirectTV.

The most visible part of a parabolic antenna is the large dish-like structure. This is called a reflector and is used to direct the radio frequency in a specific direction, thus increasing the sensitivity of the antenna when receiving data.

At the center of the parabola is the feed antenna, often called the feed horn. It is located at the focus of the reflector and is responsible for generating or receiving electromagnetic waves. The feed antenna is usually a small dipole, horn, or other type of antenna designed to transmit or capture signals.

What are the benefits of a parabolic antenna?

• High Gain: Parabolic antennas have the highest gain values. That is why they are often used to communicate with satellites in outer space.
• Highly focused: Thanks to their parabolic reflectors, these antennas can efficiently capture weak signals from distant sources. This is why they are so useful in radio astronomy, where weak signals from celestial objects need to be detected. The ability to focus on a specific area of ​​the sky is crucial.
• High Directivity: Parabolic antennas are highly directive, meaning they can focus the radiated or received energy in a specific direction. This property is beneficial for point-to-point communications, such as phone calls or satellite communications, where the ability to focus on a specific target is critical.

What are the disadvantages of parabolic antennas?

• Bulky: Parabolic antennas can be large and bulky, especially at higher frequencies. The size of a dish is directly related to the wavelength of the signal it is designed to handle. This can be a limiting factor in applications where space is limited.
• Requires precise calibration: Since parabolic antennas are able to project into outer space, they are very expensive to calibrate and maintain. This limits their use to only the most important jobs that only parabolic antennas can handle.

Summarize

As mentioned above, there are many types of antennas, and each type is suitable for specific purposes. For a compact solution, you can choose a patch antenna. For point-to-point communication, a Yagi antenna or a parabolic antenna are perfect choices. If you just need an affordable solution to broadcast radio, TV or Wifi, then a dipole or monopole antenna will be a good solution.