Array ANTENNAS Basics

An antenna that has multiple radiating elements arranged in a linear, flat, or curved shape, and that excites all or some of them, controls the amplitude and phase of the excitation current (voltage) to obtain the desired ANTENNAS directivity (radiation ANTENNAS).

• Basic configuration

As shown in Figure 1, an array ANTENNAS is composed of an array of multiple element ANTENNAS and a feed circuit that excites the element ANTENNAS.
-Widthly used element ANTENNAS are linear ANTENNAS such as dipole ANTENNAS, and ANTENNAS with low gain and wide beam widths such as slot ANTENNAS and microstrip ANTENNAS.
-Various types of power feed circuits are used, including not only simple distribution/combination circuits but also phase shifters, high-power amplifiers, and noise amplifiers.
-Array ANTENNAS can achieve a variety of ANTENNAS functions that cannot be achieved with a single ANTENNAS by changing the type of element ANTENNAS, the arrangement method, and the method of exciting the element ANTENNAS with a feed circuit.

Figure 1 Basic configuration of an array ANTENNAS

By regularly arranging a large number ANTENNAS, the combined directivity can be made sharper.

• Linear Array ANTENNAS

-As shown in Figure 2, N element ANTENNAS are arranged at equal intervals d on the x-axis, and this is called ANTENNAS ANTENNAS

• Planar array ANTENNAS

-An array ANTENNAS in which elements are arranged on a plane is called a planar array ANTENNAS.
-The arrangement shown in Figure 3 is typical.
-Directivity can be expressed as the product of the directivity of a linear array ANTENNAS. Also, the feed circuit is easy to configure.

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  Figure 2 N-element linear array ANTENNAS

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  Figure 3 Planar array ANTENNAS

The directivity of the array ANTENNAS is shown below.

• One of the functions of an array ANTENNAS is to achieve the radiation directivity required of ANTENNAS.
  This is called directional synthesis.

• Directivity synthesis provides an array ANTENNAS with the following specific functions:

-Side lobe suppression and level control are possible.
- You can specify the location of the zeros in the radiation pattern.
- Shaped beams can be achieved.

Figure 4. Array ANTENNAS directivity

Another feature of array ANTENNAS is beam steering, which electronically changes the direction of the main beam of radiation.
This can be achieved by fixing the element arrangement and giving each element an excitation phase that makes the radiation electric field of the element co-phase in a specific direction.

• Phased array ANTENNAS configuration

-As shown in Figure 5, this type of ANTENNAS has a phase shifter inserted in the feed line to change the excitation phase of each element ANTENNAS.
-This method is specifically called a phased array ANTENNAS, and is the mainstream of electronic beam steering.
-Furthermore, a system in which an amplifier is provided for each element is called an active phased array ANTENNAS.
-A method of controlling not only the excitation phase but also the excitation amplitude in the digital signal domain is called digital beamforming (Figure 6).

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  Figure 5 Phased array ANTENNAS

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  Figure 6 Active phased array ANTENNAS
  Digital beamforming with

This article describes the advantages, applications, challenges, and future of phased array ANTENNAS.

• Advantages of Phased Array ANTENNAS

-High-speed beam steering: Electronically controlled beam direction allows for target tracking much faster than conventional mechanical scanning.
- Flexible directivity: The beam direction and shape can be electronically controlled, allowing for extremely flexible directivity.

• Applications of phased array ANTENNAS

-Phase array ANTENNAS technology is used in a variety of fields, one of which is radar systems.
-In aircraft tracking and weather radar, phased array ANTENNAS help track target positions with high speed and precision.
-In military applications, it is used to quickly detect enemy movements.
Phased array ANTENNAS are also widely used in the communications field. For example, in satellite communications, beam steering is used to ensure stable reception of communications from mobile devices.
-This technology is also used in 5G communications to achieve high-capacity, high-speed data communications.

• Phased Array ANTENNAS: Challenges and Future Prospects

-Challenges include high costs and the need for complex control systems.
However, technological advances are gradually solving these problems, and advances in semiconductor technology in particular are making cheaper and smaller phased array ANTENNAS feasible.
-In the future, as phased array ANTENNAS become smaller and cheaper, it is expected that this technology will be widely used in civilian applications as well, such as in driver assistance systems for automobiles and high-speed communications on smartphones.