Aircraft Antenna Types - A two-strip blade antenna is a type of blade antenna that is a monopole whip antenna mounted on the outside of an aircraft in the form of a blade-like aerodynamic fairing to reduce air resistance. It is used by aviation radio communication systems. The dual-band type uses a "plane and cell" design to get efficient all-round coverage, so it can operate on two different radio bands.
A typical monopole antenna has an omnidirectional radiation pattern; it radiates the same radio power in all azimuth directions perpendicular to the antenna axis, the signal strength decreases to zero (zero radiation point) with the elevation angle in zit.
Aircraft Antenna Types
A monopole can be thought of as a dipole, where one d of the dipole now becomes the ground plane for said monopole. Through this line of conceptual thinking, it is easy to conclude that the radiation from a monopole antenna exists in the half-space of a similar dipole antenna. Therefore, the maximum gain is twice the maximum gain of a conventional dipole, or an additional 3 dB. Therefore, the maximum nominal value for a monopole antenna is about 5.15 dB.
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... A monopole is a dipole bisected at the third feed point and fed against the ground plane...
This article covers one type of double strip blade monopoles. This is a slot in Monopoly. Computer-aided electromagnetic modeling (CEM) is used to provide some graphics of operations for conceptual understanding.
Dual band works in dual mode, it works based on Ohm's law V = IR where V = voltage, I = current and R = resistance.
The monopole equations can be arrived at by checking the derivatives of the dipole, knowing that all radiation is half the size of said dipole. This leads to the following equations:
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This leads directly to the aforementioned maximum gain ratio to the dipole by the gain definition G = ϵ D , where ϵ is the radiation efficiency of the antenna.
A blade antenna is an attempt to create a wide range monopole (compared to a thin wire monopole). Most blade antennas are trapezoidal. This shape has been modified for aerodynamic purposes and grooves have been introduced to achieve broadband performance. This type of monopole antenna is commonly used in aviation in the UHF and UHF frequency ranges.
A slot antenna can be thought of as a dipole with opposite polarization. This is due to the conventional transmission, which places the E-field orientation at the smallest linear dimension of the aperture. The following equations can be used to "translate" a vertical or horizontal cell antenna to its complement (dipole):
Here, the subscript S gives the operation in the screening, and the subscript C gives its complement (dipole). Moreover, η = μ ϵ }}} where μ is the complex permittivity and ϵ is the complex permittivity of the medium we are radiating. This assumes an unrestricted environment. Moreover, all crack equations assume the coating thickness to be much smaller than the wavelength ( < λ 10 }} ). If this is not believed to be true, the existence and boundaries of regimes cannot be ignored.
Starboard Side Antenna Descriptions
This is defined by the Babinet principle, and Booker's Extsion extends this principle further to include polarization. The simple equations of Babinet's principle are given on the linked page provided by the author.
Dual band antennas are not a new idea. Over the years, many manufacturers have combined several elements to create antennas that operate on two separate bands (not to be confused with so-called frequency-independent antennas, such as log-period antennas).
One way to make a double-bladed antenna is to make a slot in a blade antenna with a value less than or equal to λ 10 }} so that the lower frequency does not "see" the slot (this is a simple rule of thumb). . a break in the structure less than λ 10 }} is negligible).
To the untrained eye, this may seem like a trivial process. With a little research and thought, you can realize that all local structures affect the radiation pattern by reflection, absorption, refraction, through an edge, or as part of a radiation structure. Any structure that is not local also causes these elements, including blocking and "re-radiation". With this in mind, the calculation can be difficult.
Radiation Pattern Analysis Of Aircraft Mounted Gps Antennas And Verification Through Scale Model Testing
There are several algorithms in CEM. These include, but are not limited to, Momts Method (MoM), Finite Element Method (FEM), and Uniform Theory of Diffraction (UTD). Two examples of open space software packages that use these techniques are FEKO and WIPL-D. Examples shown here are WIPL-D. Remember, these software packages must be used by someone who understands the process and can decide whether what is being calculated is accurate or whether errors in the model and input data can produce false output data (the old word garbage equals garbage disposal).
This example uses a design for biomedical telemetry with an approximate frequency of 460 MHz and GPS frequency L1 (1575.42 MHz) in one package (I hesitate to say one antenna, since there are two radio elements that require two balons for compatibility). Note that they are not compatible with any power supply line. Therefore, the design will not be practical to use. It is for demonstration purposes only.
Below you will see a simple one used for modeling. The ground plane is twice the wavelength of 460 MHz.
Below is a comparison of the transverse radiation patterns at L1 for the blade and notch. The slot shows the 8th dipole pattern in descending order. Although the blade still radiates, the gain is less and the pattern creates zeros. Please note, for a larger image, follow the link in each title or simply click on the image (it will look better if you click on the image).
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Polarization of both elements is also observed. As mentioned earlier, aperture polarization depends on its transmission, which is usually in the smallest linear dimension. This cell is polarized horizontally with respect to the ground plane, while the vane is polarized vertically with respect to the ground plane.
According to the previous section, if a dual-band blade antenna has different polarities, it can also be dual-band. The frequencies of the bands chosen for this example are relatively close and give a poor example of the power of such a device, although it does give a good indication of what can be done. When considering real estate, there are two distinct groups to cover, with good coverage and opposite polarization.
It also clearly shows that the effect of the rectangular cell radiating element on the low frequency monopole radiation pattern is negligible. This is due to the previously mentioned rule that it is advisable to keep the slot less than one-tenth of the operating frequency of the blade. Therefore, this frequency does not "see" the cell.
By combining the two elements in this way, you save on manufacturing costs and save on real estate when installing the antenna. Again, it should be noted that each emitting element has a different feed structure and may have a matching network. If you're an airplane enthusiast, you've probably wondered what all those antennas are for at some point. . How do pilots communicate with people on the ground? Where does airplane WiFi come from? What antennas do they use for what? Some of these questions have interesting answers, but none of them are complex or difficult to understand.
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On any aircraft, often inside it, you'll find dozens of antennas, each used for a different purpose. These antennas, known as aerials by many pilots, have been in the business for a while and are mainly used to help pilots communicate with other people, and most of them look like lightning bolts or other interesting protrusions.
Aircraft antennas can come in a variety of shapes and sizes, largely determined by the manufacturer. However, antennas are designed for their function more than anything else, and their shape and placement are usually determined by their directional properties and the frequencies they use to operate. Basically, these antennas have to have certain shapes and be located in certain places to work properly.
When most laymen think of airplane antennas, they assume that they are there for effective communication, and that's right. Comantennas are usually mounted on the top or bottom of the aircraft and their only concern is the effect on the fuselage shadow. Each communication transmitter has its own antenna and the antenna is mostly placed strategically because if not placed correctly, their range and coverage can be negatively affected.
The way they work is very simple and it is very important to place them in order to achieve their goal. For example, a radio that transmits an aerial antenna usually works well for communications
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