Definition of magnetic antenna
Let’s talk about the composition of the magnetic antenna, the conventional sucker antenna on the market is mainly composed of: antenna radiator, strong magnetic sucker, feeder, antenna interface of these four pieces
1, the antenna radiator material is stainless steel, pure copper, memory alloy and other materials, the shape is generally whip or rod. The magnetic antenna radiator is actually a unipolar (whip) antenna, which is a symmetric oscillator with one arm perpendicular to an ideal conductor plane (the ground). According to the antenna principle, the resonant frequency of the wire antenna is an integral multiple of 1/2 wavelength, and according to the mirror principle, on the ideal infinite plane, the ideal minimum electrical size of the magnetic antenna is 1/4 wavelength, and if the gain is to be improved, the middle loading can be used to increase the length of the antenna radiator (1/4 wavelength integral multiple).
2, the role of the strong magnetic chuck is to fix the entire antenna and ensure that the chuck antenna is in contact with the metal being sucked.
3, the feeder is generally RG series (RG58, RG174), 3D wire and so on.
4, antenna interface common are: N head, SMA, BNC, TNC, I-PEX and other interface types, among which magnetic antenna commonly used connectors are N head, SMA, BNC, TNC, etc., male and female, choose the antenna must buy the connector that matches the equipment.
The main matters of magnetic antenna use
Just to clarify for you, why does a suction dish stick to metal?
From our previous tweets, we can know that the electrical performance of the antenna is closely related to the environment in which it is used, and the resonant frequency is affected by the dielectric constant of the material around the antenna, and its use and performance cannot be separated from the design environment requirements and the installation environment.
The radiator of the suction dish antenna mentioned above is a unipolar antenna. According to the image principle, a unipolar antenna with length h and its image form a symmetric oscillator with length 2h, whose field in the upper half space is the same as that of the symmetric oscillator, and the field strength in the lower half space is zero
Generally speaking, the magnetic antenna is mainly used in the cabinet, the roof of the car or similar environment, so it is designed on the basis of various cabinet and car body models, so that the size of the metal ground part of the radio wave wavelength of the communication frequency becomes part of the antenna. Therefore, the different installation position will directly affect the change of the original design electrical parameters of the antenna, especially the resonant frequency and the radiation direction.
The radiation direction diagram of a one-quarter wavelength unipolar antenna on a finite disk (in practical use, the grounded metal disk is limited and cannot form a complete mirror image), and there is also some radiation in the lower half space (diffraction effect).
The performance of the magnetic sucker antenna is completely different when it is adsorbed on the metal body of different sizes. Therefore, when using the sucker antenna, we recommend the following two points:
1, it is required to be adsorbed on the top of the cabinet or locomotive to ensure the height and radiation direction, in order to play the best performance of the antenna; If it is installed in other parts, it will cause changes in standing wave, direction pattern and elevation Angle, affecting the communication range.
2, as far as possible to install the antenna in a wide field of vision, avoid installation in a shaft or a complex electromagnetic environment, only in this way can improve the quality of communication, reduce background noise and other unpredictable interference phenomena.
Application of magnetic antenna
When it comes to the use of magnetic antennas, let’s first talk about its advantages. If installed correctly, the suction antenna has a better standing wave ratio and higher efficiency than the built-in antenna, and no customization is required. With the glue stick antenna in the same frequency band and structure size, the gain is higher, the transmission distance is longer, and different installation positions can be selected according to the actual use needs.
In addition to the above advantages, the suction antenna also has a wide range of uses, in addition to our daily visible vending machines, express cabinets, car radio, can also be applied to wireless modules and wireless gateways with moderate gain requirements.
Magnetic antenna can be used in outdoor electric box, car. When used outdoors, the radome can be made of fiberglass and other materials, which can be waterproof and windproof.
Magnetic antenna can also be used in vending machines, the base of the antenna is a strong magnetic sucker, easy to install, not easy to fall.
Magnetic antenna can also be used in wireless meter reading, antenna structure is light, beautiful appearance
Post time: Jul-02-2023
