Today, we talk about the 40 different antenna basics and different antenna types, here we go!
Antenna definition
An antenna is an essential part of wireless transmission, in addition to the fiber optic, cable, network cable, and other transmission of wired signals, as long as the use of electromagnetic waves in the air to propagate the signal, all need various forms of antenna.
The antenna working principle
According to Maxwell’s electromagnetic field theory, “the changing electric field generates the magnetic field, and the changing magnetic field generates the electric field” so that the wireless signal propagation is realized by continuous excitation.
40 antenna basics and types introduction
Gain Factor of the 40 antenna basics and types
What is the gain factor?
The ratio of the total input power of the antenna is called the maximum gain coefficient of the antenna. It is more comprehensive than the antenna directional coefficient to reflect the antenna to the total RF power of the effective use of the degree. And expressed in decibels. Can use mathematical evidence, the antenna maximum gain coefficient is equal to the antenna directional coefficient and the product of antenna efficiency.
Antenna efficiency of the 40 antenna basics and types
What is antenna efficiency?
It refers to the antenna radiation out of the power (that is, the effective conversion of the electromagnetic wave part of the power) and the ratio of the active power input to the antenna. Is constant at less than 1 value.
Antenna polarization wave of the 40 antenna basics and types
What is the antenna polarization wave?
Electromagnetic wave propagation in space, if the direction of the electric field vector remains fixed or rotates according to certain laws, this electromagnetic wave is called polarization wave, also known as antenna polarization wave, or polarization wave. Usually, they can be divided into plane polarization (including horizontal and vertical polarization), circular polarization, and elliptical polarization.
Direction of polarization of the 40 antenna basics and types
What is the direction of polarization?
The direction of the electric field of a polarized electromagnetic wave is called the direction of polarization.
Polarization surface of the 40 antenna basics and types
What is the polarization surface?
The plane formed by the polarization direction and the propagation direction of the polarized electromagnetic wave is called the polarization plane.
Vertical polarization of the 40 antenna basics and types
What is vertical polarization?
For the polarization of radio waves, the earth is often used as the standard plane. Where the polarization plane is parallel to the earth’s normal plane (vertical plane), the polarization wave is called the vertical polarization wave. Its electric field direction is perpendicular to the earth.
Horizontal polarization of the 40 antenna basics and types
What is horizontal polarization?
Any polarization wave whose polarization plane is perpendicular to the earth’s normal plane is called a horizontal polarization wave. Its electric field direction is parallel to the earth.
Planar polarization of the 40 antenna basics and types
What is planar polarization?
If the polarization direction of the electromagnetic wave remains in a fixed direction, it is called planar polarization, also called line polarization.
Planar polarization can be obtained in the component of the electric field parallel to the earth (horizontal component) and in the component perpendicular to the earth’s surface, whose spatial amplitude has an arbitrary relative magnitude. Vertical polarization and horizontal polarization are both special cases of planar polarization.
Circular polarization of the 40 antenna basics and types
What is circular polarization?
When the angle between the polarization surface of the radio wave and the earth’s normal surface varies from 0 to 360° periodically, i.e., the electric field is constant in size and direction with time, and the trajectory of the end of the electric field vector is projected as a circle in the plane perpendicular to the direction of propagation, it is called circular polarization.
Circular polarization can be obtained when the horizontal and vertical components of the electric field are equal in amplitude and differ in phase by 90° or 270°.
Circular polarization, if the polarization plane rotates with time and becomes a right spiral relationship with the electromagnetic wave propagation direction, is called right circular polarization; conversely, if it becomes a left spiral relationship, called left circular polarization.
Elliptical polarization of the 40 antenna basics and types
What is elliptical polarization?
If the angle between the radio wave polarization surface and the earth’s normal surface changes from 0 to 2π periodically, and the trajectory of the end of the electric field vector is projected in the plane perpendicular to the direction of propagation is an ellipse, known as elliptical polarization.
When the electric field vertical component and the horizontal component of the amplitude and phase have any value (two components are equal to the exception), can get elliptical polarization.
Long-wave antenna, medium-wave antenna of the 40 antenna basics and types
What is a Long-wave antenna, or a medium-wave antenna?
Long-wave antenna and the medium-wave antenna are working in the long-wave and medium-wave band of the transmitting antenna or receiving antenna collectively. Long and medium waves are propagated by ground and sky waves, and sky waves are continuously reflected in the ionosphere and between the earth.
According to these propagation characteristics, long and medium wave antennas should be able to produce a vertical polarization of the wave.
In the long and medium wave antenna, the application of the more widely used vertical, inverted L type, T type, umbrella type vertical grounding antenna. Long and medium-wave antennas should have a good ground network.
Long and medium wave antenna has many technical problems, such as small effective height, small radiation resistance, low efficiency, narrow passband, small directional coefficient, etc. In order to solve these problems, the antenna structure is often very complex and very large.
Short-wave antenna of the 40 antenna basics and types
What is a short wave antenna?
Work in the short-wave band of transmitting or receiving antenna, collectively known as a short-wave antenna. Short-wave mainly with the help of the ionosphere reflection of the sky wave propagation is one of the important means of modern long-range radio communication.
Short-wave antenna form many, which are the most used symmetric antenna, the same phase level antenna, times the wave antenna, angle antennas, V-type antennas, diamond antennas, herringbone antennas, etc.
And long wave antenna comparison, shortwave antenna effective height, radiation resistance, high efficiency, good directionality, high gain, passband wide.
Ultra short wave antenna of the 40 antenna basics and types
What is an ultra-short wave antenna?
Work in the ultra-short wave band of the transmitting and receiving antenna called ultra-short wave antenna. Ultra-short wave mainly by space wave propagation. This antenna has many forms, which are most used in the yagi antenna, disk cone antenna, double cone antenna, etc.
Microwave antenna of the 40 antenna basics and types
What is a microwave antenna?
Work in the meter wave, sub-meter wave, centimeter wave, millimeter wave, and other bands of transmitting or receiving antenna, collectively known as a microwave antenna. Microwaves are mainly by space wave propagation, in order to increase the communication distance, antennas are erected higher.
In the microwave antenna, the wider application of parabolic antenna, horn parabolic antenna, horn antenna, lens antenna, slotted antenna, medium antenna, periscope antenna, etc.
Directional antenna of the 40 antenna basics and types
What is a directional antenna?
A directional antenna is in a particular direction or a particular direction and receives an electromagnetic wave that is particularly strong, and in the other direction and receives an electromagnetic wave is zero or a very small antenna.
The purpose of using a directional transmitting antenna is to increase the effective utilization of radiation power, and increase confidentiality; the main purpose of using a directional receiving antenna is to increase the anti-interference ability.
Undirectional antenna of the 40 antenna basics and types
What is unidirectional antenna?
In all directions of uniform radiation or receive electromagnetic wave antenna, called the undirected antenna, such as small communication machine with the whip antenna, etc.
Broadband antenna of the 40 antenna basics and types
Directional, impedance, and polarization characteristics in a very wide band almost constant antenna, called wide-band antenna.
The early broadband antenna has a diamond antenna, V-shaped antenna, times the wave antenna, disk cone antenna, etc., the new broadband antenna has a logarithmic period antenna, etc.
Tuned antenna of the 40 antenna basics and types
What is a tuned antenna?
Only in a very narrow band antenna with a predetermined direction, called a tuned antenna or tuned directional antenna.
Usually, the tuned antenna only in its tuning frequency near 5% of the band, the direction remains unchanged, and in other frequencies, directional changes are very strong, in order to cause communication to be damaged.
The tuned antenna is not suitable for a frequency change of short-wave communication. The same phase horizontal antenna, folded antenna, zigzag antenna, etc. are tuned antennas.
Vertical antenna of the 40 antenna basics and types
What is the vertical antenna?
The vertical antenna is the antenna placed vertically with the ground. It has symmetric and asymmetric two forms, and the latter is more widely used. The symmetric vertical antenna is often center-fed.
The asymmetric vertical antenna is fed between the bottom of the antenna and the ground, its maximum radiation direction in the case of height less than 1/2 wavelength, is concentrated in the ground directly, so adapted to broadcast. The asymmetric vertical antenna is also called a vertical grounded antenna.
Inverted L antenna of the 40 antenna basics and types
What is an inverted L antenna?
A single horizontal wire end is connected to a vertical lead wire and constitutes the antenna. Because of its shape like the English letter L backward, it is called an inverted L-shaped antenna.
The Russian letter of the word Γ is exactly the English letter L backward. The so-called Γ antenna is more convenient. It is a form of vertical grounding antenna.
In order to improve the efficiency of the antenna, the horizontal part of it can be used in the same horizontal line of several wires, the radiation generated by this part can be ignored, and the radiation is the vertical part.
An inverted L antenna is generally used for long-wave communication. Its advantages are simple structure, and ease to set up; the disadvantage is that it covers a large area, and durability is poor.
T-shaped antenna of the 40 antenna basics and types
What is a T-shaped antenna?
In the center of the horizontal wire, connected to a vertical lead line, the shape of the English letter T, the so-called T-shaped antenna. It is the most common kind of vertical grounded antenna. The horizontal part of the radiation can be ignored, the radiation is the vertical part.
In order to improve efficiency, the horizontal part can also be composed of multiple wires. the t-shaped antenna features the same as the inverted L-shaped antenna. It is generally used for long-wave and medium-wave communication.
Umbrella-shaped antenna of the 40 antenna basics and types
What is an umbrella-shaped antenna?
On the top of a single vertical wire, led in all directions down a few inclined conductors, so that the shape of the antenna is like an open umbrella, the so-called umbrella-shaped antenna.
It is also a form of vertical grounding antenna. Its characteristics and use of an inverted L-shaped, T-shaped antenna are the same.
Whip antenna of the 40 antenna basics and types
What is a whip antenna?
A Whip antenna is a bendable vertical rod antenna, its length is generally 1/4 or 1/2 wavelength. Most of the whip antennas are not ground and ground networks. Small whip antenna often uses the small radio station metal shell for the ground network.
Sometimes in order to increase the effective height of the whip antenna, can be added to the top of the whip antenna small spoke blade or inductor in the middle of the whip antenna. Whip antenna can be used for small communication machines, step talk machines, car radios, etc.
Symmetric antenna of the 40 antenna basics and types
What is a Symmetric antenna?
The length of the two parts is equal and the center is disconnected and connected to the feed wire, which can be used as a transmitting and receiving antenna so that the composition of the antenna is called a symmetrical antenna. Because the antenna is sometimes called the oscillator, the symmetric antenna is also called the symmetric oscillator, or dipole antenna.
The total length of half a wavelength of the symmetric oscillator called a half-wave oscillator, is also called a half-wave dipole antenna.
It is the most basic unit antenna, also used most widely, many complex antennas are composed of it. Half wave oscillator structure is simple, feed convenient, in the close range communication in more applications.
Cage antenna of the 40 antenna basics and types
What is a Cage antenna?
Cage antenna is it a kind of wide band weak directional antenna? It is a few wires surrounded by a hollow cylinder instead of a symmetric antenna in the single wire radiation body because the radiation body is cage-shaped, the so-called cage antenna. Cage antenna working band wide, easy to tune. It is adapted to the close range of the trunk line communication.
Angle antenna of the 40 antenna basics and types
What is an angle antenna?
Belong to a class of symmetric antenna, but its two arms are not arranged in a straight line, and 90 ° or 120 ° angle, a so-called angle antenna. This antenna is generally a horizontal device, its direction is not significant. In order to get wide band characteristics, the angled antenna double arm can also use a cage structure called an angle cage antenna.
Folded antenna of the 40 antenna basics and types
What is a folded antenna?
Bend the oscillator into a symmetric antenna parallel to each other called folded antenna. There are two-line folded antennas, three-line folded antennas, and multi-line folded antennas in several forms, bending, should make each line on the corresponding point of the current with the phase, from a distance, the whole antenna as a symmetric antenna.
Folded antenna and symmetric antenna, radiation enhancement. Input impedance increases, easy to couple with the feed line. The folded antenna is a tuned antenna, working frequency is narrow. It is widely used in short-wave and ultra-short-wave bands.
V-shaped antenna of the 40 antenna basics and types
What is a V-shaped antenna?
A V-shaped antenna is composed of two wires at an angle to each other, the shape of the English letter V antenna. Its terminal can be an open circuit, and can also be connected with resistance, the size of the resistance is equal to the characteristic impedance of the antenna.
The V-shaped antenna has a one-way, maximum direction of emission in the direction of the vertical plane of the sub-angle line. Its disadvantage is low efficiency and a large footprint.
Rhombus antenna of the 40 antenna basics and types
What is a Rhombus antenna?
The rhombus antenna Is a broadband antenna. It is composed of a horizontal rhombus suspended in four pillars, a rhombus of an acute angle connected to the feed line, and another acute angle connected to a rhombus antenna with a characteristic impedance equal to the terminal resistance. In the direction of the terminal resistance in the vertical plane, unidirectional.
The advantage of the rhombus antenna is a high gain, directional, uses a wide band, easy to set up and maintain; the disadvantage is a large footprint. After the deformation of the rhombus antenna, there are double rhombus antenna, back to teach the rhombus antenna, and folded rhombus antenna three forms. A rhombic antenna is generally used for large and medium-sized short-wave receiving radio.
Disk cone antenna of the 40 antenna basics and types
What is a Disk cone antenna?
A Disk cone antenna Is a kind of ultra-short wave antenna. The top is a disk (i.e., radiation body), by the heart of the coaxial line feed, and the following is a cone, connected to the outer conductor of the coaxial line.
The role of the cone is similar to the infinite ground, changing the tilt angle of the cone, can change the maximum radiation direction of the antenna. It has an extremely wide frequency band.
Fishbone antenna of the 40 antenna basics and types
What is a Fishbone antenna?
Fishbone antenna also called side shot antenna, is a special shortwave receiving antenna. By in two collection lines every certain distance connected to a symmetrical oscillator, these symmetrical oscillators are through a very small capacitor to the collection line.
At the end of the collection line, that is, the end of the direction of communication, connected to a collection line with the characteristic impedance of the resistor equal, the other end is through the feed line to the receiver.
Compared with the diamond antenna, the advantage of the herringbone antenna is a small flap (that is, the main flap direction receiving ability is strong, in other directions receiving weaker), the antenna between the mutual influence of small, occupies a small area; the disadvantage is low efficiency, installation, and use are more complex.
Yagi antenna of the 40 antenna basics and types
What is a Yagi antenna?
The Yagi antenna is also called the Yagi-Uda antenna. It has a few metal rods, one of them is a radiator, a longer radiator for the reflector, and the front of several shorter ones is the guide. The radiator is usually folded half-wave oscillator.
The antenna’s maximum radiation direction and the direction of the pilot pointing the same. Yagi antenna has the advantages of simple structure, light and strong, and easy to feed; disadvantages of narrow band, and poor anti-interference. It is used in ultra-short wave communication and radar.
Sector antenna of the 40 antenna basics and types
What is a sector antenna?
It has metal plate type and a metal wire type two forms. Among them, is the fan-shaped metal plate type, which is the fan-shaped metal wire type. This antenna widens the antenna frequency band because it increases the antenna’s cross-sectional area.
Wire-type fan antenna can be used with three, four, or five metal wires. Sector antenna for ultra-shortwave reception.
Biconical antenna of the 40 antenna basics and types
What is a Biconical antenna?
The biconical antenna consists of two cones on the top opposite cone, in the cone top feed. The cone can be made of metal surfaces, metal wire, or metal mesh.
Just like the cage antenna, due to the antenna cross-sectional area increasing, the antenna frequency band is also widened. A Biconical antenna is mainly used for ultra-shortwave reception.
Parabolic antenna of the 40 antenna basics and types
What is a Parabolic antenna?
A parabolic antenna is a directional microwave antenna, with a parabolic reflector and radiator, the radiator is installed in the focus of the parabolic reflector or focal axis. The electromagnetic wave from the radiator is reflected by the parabolic surface, forming a highly directional beam.
Parabolic reflectors are made of metal with good conductivity, there are four main ways: rotating paraboloid, column paraboloid, cut-off rotating paraboloid, and elliptical edge paraboloid, the most commonly used is the rotating paraboloid and column paraboloid.
The radiator generally uses a half-wave oscillator, open waveguide, slotted waveguide, and so on.
The parabolic antenna has the advantages of a simple structure, strong directionality, and a wide working band.
The disadvantage is: because the radiator is located in the electric field of the parabolic reflector, the reflector on the radiator’s reaction is large, the antenna and the feed line are difficult to get a good match; back radiation is larger; protection is poor; high production accuracy.
Microwave relay communication, tropospheric scattering communication, radar, and television widely used this antenna.
Horn parabolic antenna of the 40 antenna basics and types
What is a Horn parabolic antenna?
A horn parabolic antenna is composed of two parts: horn and parabolic surface. The parabolic surface is covered by the horn, and the vertex of the horn is located on the focus of the parabolic surface.
The horn is a radiator, which radiates electromagnetic waves to the paraboloid, and the electromagnetic waves are reflected by the paraboloid and focused into a narrow beam to be emitted.
The advantages of the horn parabolic antenna are: the reflector has no counter effect on the radiator, the radiator has no blocking effect on the reflected waves, the antenna matches well with the feeder; the back radiation is small; the protection degree is high; the working band is very wide; the structure is simple.
A horn parabolic antenna is widely used in trunk line relay communication.
Horn antenna of the 40 antenna basics and types
What is a Horn antenna?
The so-called horn antenna is composed of a section of the uniform waveguide and a section of a slowly increasing cross-section of the horn-shaped waveguide.
The Horn antenna has three forms: fan-shaped horn antenna, horn cone horn antenna, and conical horn antenna. The Horn antenna is one of the most commonly used microwave antennas, generally used as a radiator.
The advantage of the horn antenna is a wide operating band; the horn antenna is disadvantage the larger size, and on the same caliber, it is not as sharp as the direction of the parabolic antenna.
Periscope antenna of the 40 antenna basics and types
What is a Periscope antenna?
In microwave relay communication, the Periscope antenna is often placed in a very high bracket, therefore, to feed the antenna will have to use a very long feed line. The feed line is too long and will produce many difficulties, such as complex structure, energy loss, due to energy reflection at the feed line joints and cause distortion, etc.
In order to overcome these difficulties, a periscope antenna can be used, periscope antenna is placed on the ground by the lower mirror radiator and mounted on the bracket on the mirror reflector.
The lower mirror radiator is generally a parabolic antenna and the upper mirror reflector for the metal plate. The lower mirror radiator emits electromagnetic waves upward after the metal plate is reflected out.
The advantage of the periscope antenna is small energy loss, small distortion, and high efficiency. Mainly used in microwave relay communication of small capacity.
Spiral antenna of the 40 antenna basics and types
What is a Spiral antenna?
A spiral antenna is a kind of antenna with a spiral shape. It is composed of metal spiral lines with good conductivity, usually fed with the coaxial line, the heart of the coaxial line and one end of the spiral line are connected, and the outer conductor of the coaxial line is connected with the grounded metal network (or plate).
The radiation direction of the spiral antenna is related to the circumference of the spiral line. When the circumference of the spiral line is much smaller than a wavelength, the strongest direction of radiation is perpendicular to the spiral axis; when the circumference of the spiral line is for a wavelength of the order of magnitude, the strongest radiation appears in the direction of the spiral axis.
Antenna tuner of the 40 antenna basics and types
What is an antenna tuner?
A kind of impedance-matching network connecting the transmitter and antenna is called an antenna tuner. Antenna input impedance with frequency and a large change, and the transmitter output impedance are certain, if the transmitter and antenna are directly connected when the transmitter frequency change, the transmitter, and antenna impedance mismatch, will reduce the radiation power.
Using an antenna tuner can make the impedance match between the transmitter and the antenna so that the antenna has the maximum radiated power at any frequency. An antenna tuner is widely used in terrestrial, vehicle-mounted, naval, and aviation shortwave radio.
Log-periodic antenna of the 40 antenna basics and types
What is a log-periodic antenna?
It is a kind of broadband antenna or a frequency-independent antenna. Among them, the Log-periodic antenna is a simple logarithmic periodic antenna, its dipole length, and spacing in line with the following relationship: τ dipole by a uniform two-wire transmission line to feed, the transmission line in the adjacent dipole to swap positions between.
This antenna has a characteristic: where the characteristics of f frequency, will be repeated at all frequencies given by τⁿf, where n is an integer.
These frequencies are drawn on a logarithmic scale and are equally spaced, and the period is equal to the logarithm of τ. The name of the logarithmic periodic antenna is derived from this. The logarithmic period antenna only periodically repeats the radiation map and impedance characteristics.
But in such a structure of the antenna, if τ is not much less than 1, then its characteristics in a period of change are very small and therefore basically independent of frequency.
Logarithmic period antenna many kinds of logarithmic period dipole antennas and monopole antennas, logarithmic period resonant V-shaped antennas, logarithmic period spiral antennas, and other forms, the most common is the logarithmic period dipole antenna.
These antennas are widely used in shortwaves and shortwaves above the band.
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