Waveguide emitters have a wide pattern, low directivity, and are poorly matched to free space. To increase directivity, directivity and improve matching, they switch to horn antennas.
A horn antenna consists of a horn - a section of a waveguide with a smoothly expanding cross-section and a horn power supply - a waveguide with an exciting device.
The horn converts a section of a flat wave of small dimensions in the cross section of the waveguide into a section of an approximately plane wave of much larger dimensions in the aperture of the horn. This leads to a narrowing of the pattern and an increase in the efficiency compared to a waveguide emitter. In addition, an increase in the cross-sectional dimensions leads in most cases to the fact that the characteristic impedance of the horn tends to the characteristic impedance of free space, which improves the matching of the antenna with free space.
The main types of horn antennas include (Fig. 1) sectorial, pyramidal and conical horns.
A sectoral horn is a horn in which only one dimension of the cross-section of a rectangular waveguide increases, while the second dimension remains constant. There is an H-sectoral horn (Fig. 1 a), when the size of the waveguide in the H plane increases, and an E-sectoral horn (Fig. 1 b) when the size of the waveguide in the E plane increases.
A pyramidal horn (Fig. 1c) is a horn whose dimensions increase in both planes.
A conical horn (Fig. 1d) is a horn with an expanding circular cross-section.
Antennas in the form of an open end of a waveguide have weak directivity, and their gain is usually in the range of 6-7 dB. Such antennas are most often used as elements of phased antenna arrays, in feeds of the simplest parabolic antennas, and also as weakly directional antennas for aircraft.
To increase directivity and reduce reflection from the open end of the waveguide, horn emitters are used. In Fig. 1 a shown N-sectional horn, expanding in the plane of the vector H. A wave similar to the H 10 wave in a rectangular waveguide arises in the horn. However, a sectorial horn differs from a waveguide in that in it the wave front forms a cylindrical surface, the phase velocity is a variable quantity depending on the ratio a/l , the field at a large distance from the throat of the horn takes the form of a purely transverse wave.
The phase velocity is approximately determined by the formula 
(1) and near the horn aperture it approaches the speed of light, which leads to a decrease in the reflection of the wave from the emitting surface of the aperture.
If the horn opening angle ln is small, then the wave front in the output hole is close to flat and formula (1) can be used to calculate the pattern in the H plane. The main lobe of the pattern narrows approximately the same times as the size a of the horn aperture increases compared to the size of the wide wall of the rectangular waveguide. As the horn opening angle a n increases, the wave front in the aperture is bent, and this leads to the expansion of the pattern. The field phase at the edge of the aperture compared to its value in the middle of the aperture can be determined using an approximate formula obtained from geometric constructions:
Where R- horn length. The field phase distribution at the horn output aperture obeys a quadratic law.
As calculations show, the efficiency of a horn antenna at a fixed horn length has a characteristic dependence on the aperture size shown in Fig. 2. The presence of a maximum is explained by the fact that as the horn opening angle increases, on the one hand, the relative size of the aperture increases, which leads to a narrowing of the pattern, on the other hand
Figure 2. Dependence of directivity on the dimensions of the H-sectoral horn
according to (2), the quadratic phase error |Ф 2 | increases rapidly, leading to expansion of the pattern. As a result of the action of these two factors, at a certain electrical size of the aperture, the maximum efficiency occurs. It turns out that for any horn length, the maximum efficiency is obtained with a quadratic phase error at the edge of the horn equal to 135°. An N-sectoral horn that satisfies this condition is usually called optimal. The total CIP of the optimal H-sectoral horn is approximately 0.64 (0.81 is the aperture CIP due to the amplitude distribution falling to zero at the edges of the aperture; 0.79 is the CIP due to the quadratic phase error).
Along with H-sectoral horns, E-sectoral horns are used, expanding in the plane of the vector E. The beam width in the plane of the H-E-sectoral horn is the same as that of the open end of the waveguide, and in the E plane the beam width decreases with increasing size b, if the angle the solution is taken quite small. In an E-sectoral horn, the amplitude distribution of the field in the aperture is approximately uniform and quadratic phase error 
at the edge of the aperture, corresponding to the optimal horn with the highest directivity, is 90°. At |F 2 |<
45° ДН в плоскости Е может быть рассчитана по формуле (1).
Most widely used pyramidal horns with a rectangular cross section (Fig. 3). These horns make it possible to narrow the pattern both in the H plane and in the E plane. In a pyramidal
Rice. 3. Pyramid horn
The horn produces a spherical wave, the phase velocity of which is variable and at the open end approaches the speed of light. As a result, the reflection of the wave from the aperture is insignificant - the horn matches the waveguide with the open space. Phase distortions of the field in the aperture can be determined by formula (2) in the H plane and by a similar formula (when replacing a with b ) in the E plane. With small phase distortions (at |Ф 2 |<45 0) ДН пирамидального рупора мало отличаются от ДН синфазного прямоугольного раскрыва с соответствующим амплитудным распределением и поэтому могут быть рассчитаны по формулам (1) и (2). Для уменьшения длины рупора обычно допускается квадратичное искажение фазы поля в раскрыве |Ф 2 | = 135° в плоскости Н и |Ф 2 | =90° в плоскости Е.
Such a horn, as noted, is called optimal, and its control factor is roughly estimated by the formula, where the first factor takes into account the unevenness of the amplitude distribution in the H plane, and the second factor takes into account the presence of quadratic phase distortions in the E and H planes.
In addition to horns with a rectangular cross-section, horns with a circular cross-section are used, namely conical horns. They are formed by expanding the open end of a circular waveguide excited by an H 11 wave. The emission of a conical horn is similar to that of a pyramidal horn, and it also has optimal dimensions that can be considered as average between the sizes of the optimal E- and H-plane horns.
The advantages of horn antennas are simplicity and good range properties. Almost all optimal and longer horns can be used over the entire operating frequency band of the feed waveguide. Self-contained horn antennas are most often used in measurement installations, for example as reference antennas with a known gain. In addition, horns are widely used to feed mirror and lens antennas, as well as in other types of antenna designs, such as impedance ones.
The main disadvantage of a horn antenna is the presence of phase distortions in the aperture. To reduce these distortions, it is necessary to increase the length of the horn.
To obtain, for example, a pattern width equal to 5°, the length of the H-horn must be more than 60 l, i.e. the horn turns out to be very bulky. This shows that the formation of sharp patterns using conventional horn antennas is difficult. This drawback can be eliminated in several ways:
1) using multi-horn antennas. An aperture of size L is formed by n horns with apertures L/n. In this case, the length of the antenna R can be reduced by n^2 times. This method, however, greatly complicates both the antenna itself and its power supply system;
2) correction of phase distortions using phase equalizing devices. The latter are either dielectric lenses installed in the horn aperture (Fig. 4 a) or geodesic (metal-air) lenses (Fig. 4 b). The profile of the geodetic lens is selected so that
if the length of the geometric path from the top of the horn to any opening point were the same. Obviously, the use of geodesic lenses is only possible in vectorial horns. Horn antennas have a number of valuable qualities: they are simple in design, range, and have a relatively low level of side lobes. However, they are inconvenient for creating narrow patterns due to the limitations imposed by phase distortions of the field in the aperture. Horn antennas without phase correction are used to form wide patterns (tens of degrees). Such antennas are widely used as feeds for mirror and lens antennas and as antennas for measuring instruments.
To form narrow patterns (a few degrees), horn antennas with phase-equalizing devices are used. Even sharper patterns can be obtained using systems of a large number of horns - antenna arrays.
Bibliography:
1. Markov G.T., Sazonov D.M. Antennas. – M.: Energy, 1975.
2. Shifrin Y.S. Antennas. VIRTA named after. Govorova L.A. 1976.
3. Gavelya N.P., Istrashkin A.D., Muravyov Yu.K. Serkov V.P. Antennas. Ed. Muravyova Yu.P. VKAS. 1963. Part 1, part 2.
Federal Agency for Education of the Russian Federation
Krasnoyarsk State Technical University
Horn antennas
Completed by: Art. gr. R 52-4
Sholotov P.A.
Checked by: Puzikov G.S.
The horn antenna belongs to the class of so-called aperture antennas. Aperture is the effective opening area of the antenna. Such antennas, unlike wire antennas, “catch the wave” directly with their aperture, and a horn antenna is a prime example of this. It's similar to how a blue whale catches plankton. The more it opens its mouth (aperture), the more plankton ( electromagnetic energy) will catch. In other words, the gain of a horn antenna is directly proportional to the opening area of the horn, and we can achieve impressive gain simply by increasing its size. Horn antennas are widely used in professional radio relay communications or as dish feeds.
By making a simple horn antenna with our own hands without special phase-equalizing tricks, such as an H-shaped horn, we can achieve a gain of up to 20-25 dBi. The advantages of a horn antenna include the fact that it is quite broadband and, therefore, has good repeatability, has a fairly simple design with a relatively large gain. Among the disadvantages, we can mention the high consumption of material in comparison, for example, with a panel patch antenna, which has the same gain, as well as a large windage. Many anonymous people are put off by the use of horn antennas as measurement standards in professional equipment. Where are we going with our tins? Well, is it comme il faut to use a tin can as an antenna instead of a piece of round waveguide? But it works! For most anonymous people, getting foil fiberglass, and even more so copper plates or something like that, is quite problematic and expensive. Therefore, using galvanization to make a horn antenna with your own hands is not only acceptable, but also economically justified. Moreover, you can use plywood or cardboard in combination with metal foil. You can see one of these designs at the link at the end of the article.
Horn antennas are divided into:
- conical
- sectoral
- pyramidal
- corrugated
Pyramid horn antennas are best suited for making your own. You can calculate the design dimensions of such an antenna using our online calculator. The electromagnetic energy collected by the horn enters a section of a rectangular waveguide. Inside the waveguide there is a coaxial-waveguide junction, approximately the same as that of a can antenna. By changing the size and position of the pin, you can match the antenna over a wide range with both 75-ohm and 50-ohm feeders.
Rice. Types of horn antennas: a) E-sectoral, b) N-sectoral, c) pyramidal, d) conical.
Properties:
Horn antennas are very broadband and match the feed line very well - in fact, the antenna bandwidth is determined by the properties of the exciting waveguide. These antennas are characterized by a low level of the rear lobes of the radiation pattern (up to -40 dB) due to the fact that there is little flow of RF currents to the shadow side of the horn. Horn antennas with low gain are simple in design, but achieving high (>25 dB) gain requires the use of wave phase-aligning devices (lenses or mirrors) in the horn aperture. Without such devices, the antenna has to be made impractically long.
Application:
Horn antennas are used both independently and as feeds for mirror and other antennas. A horn antenna, structurally combined with a parabolic reflector, is often called a horn-parabolic antenna. Horn antennas with low gain are often used as measurement antennas due to their favorable set of properties and good repeatability.
At the Holmdale radio telescope, which is a Dicke radiometer based on a horn-parabolic antenna, Arno Penzias and Robert Woodrow Wilson discovered the cosmic microwave background radiation in 1965.
Characteristics and formulas:
The gain of a horn antenna is determined by its opening area and can be calculated using the formula:
where: - horn opening area.
λ is the wavelength of the main radiation.
- 0,4....0,8 instrumentation(horn surface utilization factor), equal to 0.6 for the case when the path difference between the central and peripheral beams is less, but close to Pi/2, and 0.8 when wave phase-leveling devices are used.
Main lobe width DNA H:
Main lobe width DNA by zero radiation in the plane E:
Since with equality L E And L H
DNA in the plane N turns out to be 1.5 times wider; often, to obtain the same petal width in both planes, choose:
To keep phase distortions in the horn aperture within acceptable limits (no more than Pi/2), it is necessary that the following condition be met (for a pyramidal horn):
where and are the heights of the faces of the pyramid forming the horn.
From another source:
Where L H- opening width in plane N,
L E- opening width in plane E,
R E And R H- horn length.
For such an antenna KND in a simplified form it is calculated using the formula:
D RUR = 4piνS/λ 2
Where: S = L H * L E- horn opening area;
λ
- wavelength of the main radiation;
ν
= 0.4....0.8 - surface utilization coefficient ( instrumentation);
Depending on the type of horn, horn antennas are divided into N- And E- sectorial, pyramidal and conical. Horns whose dimensions correspond to the maximum value KND are called optimal. For optimal N-sectoral horn antennas horn length R H =L H 2 /3λ, for optimal E-sectoral horn antennas R E =L E 2 /2λ. instrumentation optimal N- And E-sectoral, pyramidal horns is 0.64. If we conditionally increase the length of the horn to infinity, then instrumentation antenna will increase to 0.81.
In a conical horn, optimal length R opt. con. depends on the diameter of its opening
d:
R opt. con. = d 2 /2.4λ + 0.15λ
instrumentation optimal conical horn v=0,5.
Table 1.2. Horn radiation pattern width with optimal length.
|
Horn type |
Radiation pattern width in the H plane |
Radiation pattern width in plane E |
|
E-sectoral |
2Θ 0.7 =68λ/L H |
2Θ 0.7 =53λ/L E |
|
H-sectoral |
2Θ 0.7 =80λ/L H |
2Θ 0.7 =51λ/L E |
|
Pyramidal |
2Θ 0.7 =80λ/L H |
2Θ 0.7 =53λ/L E |
|
Conical |
2Θ 0.7 =60λ/d |
2Θ 0.7 =70λ/d |
If we take an elliptical horn with an ellipse axial ratio of 1.25, then we can obtain approximately the same width of the radiation pattern in all sections passing through the horn axis.
The advantage of a horn antenna is its broadband, determined by the broadband of the feeding waveguide, efficiency. horn antenna is equal to unity.
The disadvantage of horn antennas is that the horn length must be too long to obtain highly directional radiation. The optimal horn length is proportional to the square of the aperture dimensions L H or L E, and the width of the radiation pattern is inversely proportional L H or L E in the first degree. Therefore, to narrow the radiation pattern of a horn antenna in N times, the opening width should be increased by N times, and the length of the horn is in N2 once. This circumstance imposes restrictions on the width of the radiation pattern of horn antennas.
At 2.45 GHz, the WiFi signal wavelength is 122 mm. Polarization is vertical. The network provides an interesting diagram of a biquadrat curved around a copper pipe with a diameter of 10 cm. It turns out that the radiation pattern of such an antenna is distorted and stretched in azimuth. There are no MMANA models to see exactly what happens, but amateurs argue that this move is not the best (we'll look at that later). Horn antennas are suitable for high frequencies, but are too bulky for low frequencies. Is it possible to make an antenna for a router with your own hands in the form of a speaker. In exceptional cases (imitation of the voice of a lake duck), definitely yes.
Few people think about the physical meaning of the antenna. The average person will answer that an antenna is necessary to amplify the signal, but it is a passive, non-amplifying device. It collects a signal from a large area and sends it to a small one, where the receiver cable is located. All antennas do this without exception. What can a vibrator collect? Suffice it to remember that a wave vibrator (a piece of wire equal to the wavelength) is better than a half-wave vibrator, which has an advantage over a quarter-wave vibrator (equal to a quarter of the wavelength). The longer the vibrator, the more effective. In this case, certain proportions are observed. This is dictated by the wave laws of nature.
It is known that an opera singer, after hitting a high note, breaks a crystal glass. How it's done. The singing master hits the instrument lightly and listens to what note flows from the vessel. This is the resonant frequency of the object. By playing the same note with a trained voice, the singer evokes a response from the container. The oscillations accumulate, intensify, and do not die out. As a result, the glass breaks into pieces. Exactly the same thing happens in the antenna. Collects and transmits waves that are resonant. And this is the fundamental frequency and harmonics (multiplied by two, four, etc. frequencies). A homemade antenna for a router will help weed out the unnecessary. The signal will be concentrated in the right place.
It is important to connect the wire to the antenna correctly. Reception of waves and harmonics will make it possible to produce a harmonic antenna that receives frequencies whose half-waves are multiples of the dimensions of the device.
For example, frequencies related as 1: 2: 4: 6, etc. A properly drawn line will allow you to catch several waves at the same time. If you break the rules, the device will not work. Here's how to do it:
- Draw a schematic diagram of a vibrator (straight line), on which the laws of distribution of currents and voltages for all wavelengths are schematically indicated.
- If you connect the wires at the voltage antinode point, you get voltage power supply.
- If you connect the wires at the antinode point of all currents, you get current feeding.
This is how harmonic antennas are made. To make something like this, for example, for a frequency of 3.7 MHz (HF range), you need a piece of wire 80 meters long. It is clear that such a situation may not suit you. Therefore, new designs are constantly being searched for. Not long ago they published a description of the process of constructing a ferromagnetic antenna for the 3.7 - 7 MHz range that fits in a fist. We do not claim that it will replace 80 meters of copper, but researchers have observed a positive effect from it, which is used in radio receivers.
Horn antennas for router
What will please you with a horn amplifying antenna for a router. Simple in design. Here's the theory:
- pyramidal (truncated pyramid);
- sectorial, sectorial (a sector made of a waveguide, the bottom and ceiling are parallel to each other, the sides diverge);
- conical (truncated cone);
- hybrid (the shape of the horn can hardly be called a coined word; those who have disassembled satellite converters are familiar with a horn with steps).
If horns are used in satellite communications at frequencies above 5 GHz, then they are also suitable for WiFi. How to make an antenna for a router. Horns belong to the class of microwave devices. The antenna is made of steel plated inside. This improves conductivity conditions, allows the wave to move freely inside, and gives the walls hardness. In practice, cardboard covered with foil inside is suitable for a glazed loggia. Foil, as you know, is made of aluminum; copper has the best qualities. Some people assemble horn antennas from PCB. Then the surface is polished, for example, with an eraser, and varnished. Seal the horn antenna portal with dielectric, plastic, foam, etc.
Important! Without foil, the horn will not work for obvious reasons. A dielectric cannot reflect electromagnetic radiation.
The joints, in the case of PCB, are soldered, the cardboard is glued. It's probably better to take plywood, because the correct geometry is important for the antenna. And the veneer sheet holds its shape better. The inside needs to be glued at the seams, and the outside needs to be coated with a primer that prevents moisture from penetrating inside. Next, it is painted and hung anywhere. If desired, it is possible to attach a bird feeder at the top. Cover the inside of the structure with foil, as evenly as possible (the evenness of the pasting will not affect the operation of the antenna). We suggest making a pyramidal horn, which is simpler and will provide an acceptable radiation pattern and elevation in case strangers want to get into our network.
The radiation pattern of a horn antenna for a router is not original. This is a petal, 15 degrees wide (depending on the design) in azimuth and elevation. This determines the specific application. To cover the house, the antenna is placed at the height of the middle distance away. So that the main petal covers all consumers. Let's start with the dimensions of the supply waveguide, which receives little attention. There is a calculator on the website http://users.skynet.be/chricat/horn/horn-javascript.html; use it to calculate the parameters by substituting the frequency. The default is channel 6 (2437 MHz).
The bottom of the supply waveguide is pierced from below by a pin spaced from the rear wall by a quarter of the wavelength, and the length of the section is half the wavelength. Using a formula from physics, we find the wavelength: 299792458 / 2430000000 = 123 mm. This is the wavelength in free space. There is a critical wave in the waveguide; it cannot work below it. The value is equal to twice the long side of the waveguide. Let's follow the advice of the calculator and take walls 90 x 60 mm. The critical wave length will be 180 mm. Inside the waveguide, the wave moves at an angle. Consequently, the wavelength increases, equal to the quotient of the wavelength in free space divided by the cosine of the angle of motion inside.
The difficulty is finding the angle. Special formulas have been developed for the calculation; readers will find them on their own, but we will use the results. Initially, the calculator asks you to specify the dimensions of the horn. Let's give the correct values. Using the method, we find the sides of a parallelepiped that includes the opening of the horn (without a supply waveguide). It turns out:
- Length P – 60 cm.
- Width H – 25 cm.
- Height E – 10 cm.
The dimensions of the external portal are found, and the internal one is equal to the entrance to the waveguide. This will determine the geometry of the four walls. Click on Compute and you will get a ready-made template. Pay attention to the Aperture Quality column. It should contain a figure less than 1/8 of a wave (in this case, 15 mm). A quarter was published with the original data from the site, but the author is not sure of its accuracy. Do not glue the first model tightly, but test it first on the ground. Please note that we have already calculated the wavelength in the waveguide, the figure is 16.85 cm. Now we understand what to do with the rod:
- distanced from the rear blanked wall of the waveguide by 168.5 / 4 = 42.125 mm;
- the waveguide section has a length of 84 mm;
These are important parameters and should be strictly followed. Here the signal is removed from the pin. How to set up a site. The pin protrudes from the bottom to a certain length, this is a quarter of a wave in free space (31 mm). You need to take the SWR meter and move it in different directions until you get a value in the unity region. If it doesn’t work for a long time, then tilt the rod slightly towards the back wall.
Well, the external antenna of the WiFi router is ready. Next there will be a conversation about microwave technologies.
A horn antenna is a structure consisting of a radio waveguide and a metal horn. They have a wide range of applications and are used in measuring equipment and as an independent device.
What is this
A horn antenna is a device that consists of an open-ended waveguide and a radiator. In shape, such antennas are H-sectoral, E-sectoral, conical and pyramidal. The antennas are wide-band, they are characterized by a small level of lobes. The horn design with force is simple. The amplifier allows it to be small in size. For example, or lenses align the phase of the wave and have a positive effect on the dimensions of the device.
The antenna looks like a bell with a waveguide attached to it. The main disadvantage of the horn is its impressive parameters. In order to bring such an antenna into working condition, it must be located at a certain angle. That is why the horn is longer in length than in cross-section. If we tried to build such an antenna with a diameter of one meter, it would be several times longer. Most often, such devices are used as a mirror irradiator or for servicing radio relay lines.
Peculiarities
The radiation pattern of a horn antenna is the angular distribution of power or energy flux density per unit angle. The definition means that the device is broadband, has a supply line and a small level of back lobes of the diagram. In order to obtain highly directional radiation, it is necessary to make the horn long. This is not very practical and is considered a disadvantage of this device.
One of the most modernized types of antennas include parabolic horns. Their main feature and advantage are low side lobes, which are combined with a narrow radiation pattern. On the other hand, parabolic horn devices are large and heavy. One example of this type is the antenna installed on the Mir space station.
In terms of their properties and technical characteristics, horn devices are no different from those installed in mobile phones. The only difference is that the latter have compact antennas and are hidden inside. However, miniature horn antennas can be damaged inside a mobile device, so it is recommended to protect the phone case with a case.
Types
There are several types of horn antennas:
- pyramidal (made in the shape of a tetrahedron pyramid with a rectangular cross-section, used most often);
- sectoral (has a horn with H or E extension);
- conical (made in the form of a cone with a round cross-section, emits circularly polarized waves);
- corrugated (horn with a wide bandwidth, low level of side lobes, used for radio telescopes, parabolic and satellite antennas);
- horn-parabolic (combines a horn and a parabola, has a narrow radiation pattern, low side lobes, operates at radio relay and space stations).
The study of horn antennas allows you to study their operating principle, calculate the radiation patterns and antenna gain at a certain frequency.
How does it work
Horn measuring antennas rotate around their own axis, located perpendicular to the plane. A special detector with amplification is connected to the output of the device. If the signals are weak, a quadratic current-voltage characteristic is formed in the detector. Electromagnetic waves are created by a stationary antenna, the main task of which is to transmit horn waves. In order to remove the directional characteristic, it is turned around. Then readings are taken from the device. The antenna is rotated around its axis and all changed data is recorded. It is used to receive radio waves and ultrahigh frequency radiation. The device has huge advantages over wire-based units, as it is capable of receiving a large volume of signal.
Where is it used?
The horn antenna is used as a separate device and as an antenna for measuring devices, satellites and other equipment. The degree of radiation depends on the opening of the antenna horn. It is determined by the size of its surfaces. This device is used as an irradiator. If the design of the device is combined with a reflector, it is called horn-parabalic. Amplified units are often used for measurements. The antenna is used as a mirror or beam feed.
The inner surface of the horn can be smooth, corrugated, and the generatrix can have a smooth or curved line. Various modifications of these emitting devices are used to improve their characteristics and functionality, for example, in order to obtain an axisymmetric diagram. If it is necessary to correct the directional properties of the antenna, accelerating or decelerating lenses are installed in the aperture.
Settings
The horn-parabolic antenna is tuned in the waveguide part using diagrams or pins. If necessary, you can make such a device yourself. The antenna belongs to the aperture class. This means that the device, unlike the wire model, receives the signal through an aperture. The larger the horn of the antenna, the more waves it will receive. Strengthening is easy to achieve by increasing the size of the unit. Its advantages include broadband, simplicity of design, and excellent repeatability. The disadvantages are that when creating one antenna, a large amount of consumables is required.
To make a pyramid antenna with your own hands, it is recommended to use inexpensive materials, such as galvanized steel, durable cardboard, plywood in combination with metal foil. It is possible to calculate the parameters of the future device using a special online calculator. The energy received by the horn enters the waveguide. If you change the position of the pin, the antenna will operate over a wide range. When creating a device, keep in mind that the inner walls of the horn and waveguide must be smooth, and the bell must be rigid on the outside.
