A plane reflector antenna is one of the four types of reflector antennas. So, what is a reflector antenna? Well, it’s a type of antenna that’s used to eliminate any backward radiation as well as increase the signal strength in the desired direction.
The elimination of backward radiation is possible by putting a reflector behind the feed antenna elements. There are four shapes of reflectors used to make a reflector antenna and that’s how they’re categorized into four.
Since a plane reflector is set behind the feeder to get maximum gain in the desired direction, this type of antenna is called a plane antenna. Let’s take a deeper look into the workings of a plane reflector antenna, its uses, and some basics.
What is A Plane Reflector Antenna?
A plane reflector antenna is one that blocks radiation from the antenna feed by placing a plane reflector behind the feeder. The antenna can be oriented both vertically or horizontally. You can construct the feeder with a dipole antenna, Yagi-Uda, horn antenna, spiral antenna, ring-focus antenna, or other ones.
Here’s how a plane reflector antenna is structured. The two main parts are the feed, which is called the active element, and the reflector, also known as the parasitic element.
Its frequency of operation can be in the microwave frequency range, that’s between 1-100 kHz or even beyond that. Because of this range, it’s great for satellite communication as well as other long-distance communications.
Basics of Plane Reflector Antenna
There are a lot of interesting things to learn about a plane reflector antenna. The following are the most basic facts.
- It’s the simplest form of a reflector antenna that was designed to direct energy in the actual directions intended.
- They’ve been around longer than other types of reflector antennas ever since the immediate years that followed Hertz’s discovery of electromagnetic wave propagation that happened in 1888.
- The radiation source or feed can be placed in both horizontal and vertical orientations.
- According to Antenna Theory, the position of the reflector and polarizing the radiation source effectively control radiation characteristics like pattern, directivity, and impedance.
- Physicists use Image Theory for analysis of the radiation pattern in plane reflector antennas.
- Out of the three reflector antennas, the plane reflector has the least directivity. It reflects the radiation in such a way that the reflected waves are more in a curve shape.
What Are The Other Types of Reflector Antennas?
Apart from plane reflector antennas, here are the other major categories of reflector antennas.
- Corner Reflector Antenna
Two plane reflectors when joined together to form a corner reflector and then set up with an antenna feed, it’s called a corner reflector antenna.
They are better at directing the antenna signals in the desired direction as the reflected waves produced by them are less curved.
- Parabolic Reflector Antenna
This type of reflector antenna is more widely used. As you can guess, when a parabolic reflector is used to reflect the signals coming from the feed, it’s called a parabolic reflector antenna.
A parabolic antenna performs best out of the four when it comes to directiveness. The radiating waves produced by them are straight.
- Spherical Reflector Antenna
The spherical reflector comes in handy for wide-angle scanning and performs better for this task than a parabolic reflector antenna. This is because of its perfect symmetry. However, that can serve as a disadvantage for other functions.
Why is Plane Reflector Antenna Important?
Plane reflector antennas are too simple to serve complicated functions on their own and have limited efficiency.
But they’re the building blocks of all the experimentation done on building reflectors that were responsible for many modern-day achievements, including man’s landing on the moon and building communication frameworks.
They’re responsible for the building of more sophisticated configurations of reflector antennas as well as developing and analysis of experimental design techniques.
Because of that, reflector antennas are now used in radars, remote sensing, band satellite communication, radio astronomy, imaging performance, and tracking.
They successfully result in desired radiation patterns, like multifrequency, contour beam, pencil beam, polarization, narrow beam, center beam, transmit beam, etc.
Types of Plane Reflector Antennas
There are basically 2 types of plane reflector antennas based on their orientation.
Horizontal Plane Reflector Antenna
When the reflector is placed behind a horizontal dipole antenna, it’s a horizontal plane reflector. You build the reflector antenna horizontally or vertically based on the radiation pattern that best suits your need. A suitable design will help target the direction of arrival of the signal. Choosing between the two types is essential as they don’t radiate in the same direction.
The above picture shows the radiation pattern of a horizontal dipole antenna over a plane reflector.
Vertical Plane Reflector Antenna
The reflector that is built with a vertical dipole antenna as a feeder and a plane reflector as the parasitic element will fall under this category. Here’s how the radiation pattern looks in such an antenna.
Tips About Designing A Plane Reflector Antenna
Making a plane reflector antenna system design is easier than other reflector antennas. However, there are still a lot of things to consider, for example, the antenna tilt angle, which antenna to use as feed, the distance between feed and reflector, etc.
We have some tips for you regarding the antenna feed you use to help make a good design.
Tip 1
Although you can use a small microstrip array as a way to feed your plane reflector antenna, one of the disadvantages of doing so is the small impedance bandwidth you get from it.
But you can reduce this effect by reduction of the antenna feed’s profile as low profile feed have higher impedance bandwidth.
Tip 2
If you want to design a plane reflector antenna with a folded diode then you need to know the location of the phase center of the folded diode. It’s not easy to do as this position changes as the distance of observation does.
A designer needs to make sure that the phase center of the folded dipole is located at the same level as the ground plane of the plane reflector.
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FAQs
What are the advantages of reflector antennas?
You can get high gains from reflector antennas, especially a parabolic reflector antenna. But the main benefit is the ability it gives to control the direction of the waves and prevent them from going in a backward direction. They also offer narrow beam widths.
What is the aperture efficiency of an antenna?
It’s a variable meant to measure the reduction in the gain of an antenna that is caused by various factors. When aperture efficiency is less, it means the antenna isn’t able to gain as much as it has the potential to. Shape errors, feed spillover, feed illumination taper, etc. can cause the aperture efficiency to drop for reflector antennas.
How can you analyze the performance of a reflector system?
You can analyze the performance of a reflector system in one of two ways. The first is, the aperture distribution method while the other is the current distribution method.
Final Words
Reflector antennas have changed the world as we know it just by steering directions of the signals. They are essential for broadcasting satellite communication, remote sensing, radars, etc. Without them, many of the technology that we take for granted today wouldn’t have been possible.
Starting from simple designs, reflector antennas can grow to be more complex and sophisticated. A plane reflector antenna has very limited scope but one can’t deny that it’s where the journey began paving the way to the world as we know it today.