Principle and calculation of quarter wavelength antennas https://www.whwireless.com/  Estimated 5 minutes to finish reading Quarter wavelength antennas are more common in areas such as walkie-talkies, and their name is more technical than that of antennas that are distinguished by their shape. In this article, we will further discuss the characteristics of the quarter wavelength antenna by looking at the principles and applications of this antenna. First, the antenna's transmission principle Regarding the quarter wavelength antenna, we need to understand the basic principle of the antenna's emission first. Electricity travels through a conductor at a speed close to that of light, and when it encounters a discontinuity in the conductor, it is reflected back to the signal source. If the current is alternating and the reflected current returns to the origin or feed point at the right moment, then the current is reinforced by the subsequent cycles so that only a small amount of energy is required to maintain a standing wave within the antenna. That is, due to the presence of standing waves so that the antenna is in a resonant state. Thus transmitting electric waves into space. In the resonant state, the voltage in the current for the maximum of the midpoint (oscillator of the midpoint) is very little, but at both ends there is a great value, Ohm's law applies to the antenna, in the midpoint due to the current, the voltage is low, so the resistance is small, at both ends of the situation is exactly the opposite, thus the impedance is high.   Second, the principle and application of quarter wavelength antenna According to the theory of transmission line, 1/4 wavelength open line is equivalent to a series resonant circuit, so its entire load is purely resistive, in some occasions, due to environmental factors, the length of the antenna is often limited, so there is a loaded antenna. According to the theory of transmission line, the length of the antenna is less than 1/4 wavelength multiples of its impedance is capacitive, when the antenna does not resonate, for this reason we can add an inductor on the antenna to balance with the antenna, so that the antenna resonance, we call this antenna for loading antenna. Theoretical and practical evidence, when the length of the antenna for the radio signal wavelength of 1/4, the antenna transmission and reception conversion efficiency is high. Compared to one-half wavelength, full wavelength, antenna size is much smaller, compared to the antenna transmitting and receiving efficiency and the highest ratio of antenna size, so commonly used quarter wavelength antenna. Third, how to calculate the quarter wavelength A quarter wavelength can be calculated by frequency, the formula is: the length of the antenna (in meters) = (300/f) * 0.25 * 0.96, f indicates the frequency in MHz, 0.96 is the wavelength shortening rate (electromagnetic wave propagation in the antenna, some factors lead to wavelength shortening...

How to install outdoor antenna? Introduction to 5 specifications https://www.whwireless.com/ Estimated 5 minutes to finish reading Compared with the indoor antenna, the outdoor antenna needs to consider the surrounding complex environment, and there will be many points to pay attention to in the installation. This paper will focus on the five installation specifications of outdoor antenna and introduce how to operate it correctly. 1、 Tower side installation of directional antenna 2.4 GHz, 14 DBI, 90 ° sector antenna, vertical polarization, integrated n-type female connector In order to reduce the influence of the antenna tower on the antenna directivity pattern, it should be noted during installation that the distance from the center of the directional antenna to the tower is λ/ 4 or 3 λ/ 4, the maximum directivity outside the tower can be obtained. 2、 Tower side installation of omnidirectional antenna 2.4 GHz 7 DBI omnidirectional Mini Pro Series antenna - n-type female connector In order to reduce the influence of the antenna tower on the antenna directivity pattern, in principle, the antenna tower cannot become the reflector of the antenna. Therefore, during installation, the antenna should always be installed on the edges and corners, and the nearest distance between the antenna and any part of the tower should be greater than λ。 3、 Multi antenna common tower To minimize the coupling and interaction between the receiving and transmitting antennas of different networks, and try to increase the isolation between antennas, the best way is to increase the distance between them. When the antenna is in the same tower, the vertical installation shall be preferred. 4、 Traditional monopolar antenna (vertical polarization) Due to the isolation (≥ 30dB) between antennas (rx-tx, tx-tx) and the requirements of spatial diversity technology, there is a certain horizontal and vertical separation distance between antennas. Generally, the vertical distance is about 50cm and the horizontal distance is about 4.5m. At this time, infrastructure investment must be increased to expand the platform for installing antennas. 5、 Dual polarization antenna (± 45 ° polarization) Since the polarization orthogonality of ± 45 ° can ensure that the isolation between + 45 ° and - 45 ° antennas can meet the requirements of intermodulation on the isolation between antennas (≥ 30dB), the spatial spacing between dual polarization antennas only needs 20-30cm. The mobile base station does not need to build an iron tower, but only needs to erect an iron column with a diameter of 20cm, and fix the dual polarization antenna on the iron column according to the corresponding coverage direction. Antenna spacing: 1. Diversity receiving antenna in the same cell: > 3M 2. Horizontal spacing of omnidirectional antenna: > 4m 3. Horizontal spacing of directional antenna: > 2.5m 4. Vertical spacing of antennas on different platforms: > 1m It should also be noted that the transceiver an...

The reasons for the use of antenna covers and classification details https://www.whwireless.com/  Estimated 5 minutes to finish reading Outdoor antennas are often attacked by wind and rain, resulting in the reduction of antenna transmission capacity, so we also need a protective device to maintain the normal operation of the antenna. Antenna cover is a structure to protect the antenna system from external environment, it has good electromagnetic wave penetration characteristics in electrical performance, mechanical performance can withstand the role of external harsh environment. This article will discuss the purpose and classification of antenna masks from the point of view of why they are needed. Radome for parabolic antenna, 400mm diameter I. Why do we need a radome? 1、Protect the antenna system from wind and rain, ice and snow, sand and dust and solar radiation, make the antenna system work more stable and reliable, at the same time reduce the antenna system wear, corrosion and aging, prolong the service life. 2, eliminate wind load and wind moment, reduce the driving power of the rotating antenna, reduce the weight of the mechanical structure, reduce inertia and improve the inherent frequency. 3、The relevant equipment and personnel can work inside the cover, not affected by the external environment, improve the efficiency of the use of equipment and improve the working conditions of the operator. 4, for high-speed flight of the aircraft, the radome can solve the high temperature, aerodynamic load and other load to the antenna brought about by the problem. However, it should be noted that the radome is an obstacle in front of the antenna, which will produce absorption and reflection of the antenna radiation wave, change the free space energy distribution of the antenna, and affect the electrical performance of the antenna to some extent. → Cause analysis. The reflection of the antenna hood wall and the uneven part of the bypass will cause the antenna main flap electric axis offset, thus producing aiming error; The antenna hood on high frequency energy absorption and reflection will cause transmission loss, thus affecting the antenna gain (receive when the system noise temperature increase); The antenna hood caused by the antenna flap distortion, so that the antenna main flap width change, zero depth increase and side flap level increase. 1710~2700MHz 6dBi gain omni-directional PRO series antenna, N-type female connector, glass fiber radome Second, the classification of the radome 1, From the use of the two categories of aviation type and ground (including ship) type. 2, from the electrical according to the antenna radiation wave incidence angle is divided into vertical incidence radome and large incidence angle radome. Radiation wave rays and the angle of the wall normal for the angle of incidence. The angle of incidence is less than 30°, called vertical incidence radome. Antenna in the hood scan to any position, the incidence angle of c...

The structure of antenna radome and the 5 main types www.whwireless.com Estimated 6 minutes to finish reading We have already introduced the advantages of antenna radomes before, in this article we will start with the structure of radomes and discuss their main structural forms, as well as the material composition and specific use of radomes under different structures. I, the structure design of the antenna radome The difference between the structure of the radome and other building structures is that the design of the structure type, component size, cover wall thickness, material selection and structural details must be considered electrical characteristics. 1. Canopy wall thickness: related to the working wavelength. Electrically, in order to minimise reflections, a uniform single wall thickness or core thickness of the sandwich structure must be designed according to the working wavelength. However, the chosen wall thickness must be able to withstand the expected maximum aerodynamic load and other loads without being damaged or without producing large deformations. The specific choice of wall thickness should be based on the working wavelength, radome size and shape, environmental conditions, materials used in electrical and structural performance of each other. 2, material selection: the radome wall media materials to be considered factors are: in the working frequency of the dielectric constant and loss angle tangent to low, to have sufficient mechanical strength. Generally speaking, the inflatable radome commonly used coated with sea Palon rubber or neoprene polyester fiber film; rigid radome with glass fiber reinforced plastic; sandwich structure in the sandwich more with honeycomb core or foam. Aviation radome generally with glass fiber reinforced plastic, ceramic, glass - ceramic and laminate. 3, specific structure: the uneven part of the radome will cause high frequency energy bypass and reflection, therefore, in the radome wall where the high frequency energy through the part generally should not set reinforcement, because it may make the shell radome produce local or overall instability, or produce large deformation, thus bringing many restrictions to the structural design and cover size. In order to facilitate the manufacture, installation and transportation, must be made into a large rigid radome block type, spherical connection shall be set flange, resulting in the cover wall is not uniform. Therefore, in the design generally through the electrical performance test and structural performance test, to find a good overall performance of the connection scheme. In addition, the metal components or metal connections used should be such that their electrical shading is minimised. 700/960/1710/27003800/4800MHz 8dBi gain 5G 4G omni-directional PRO series antenna, N-type female connectorX2 WH-5G-MM8x2 Second, the introduction of 5 kinds of common antenna cover 1、Aerial antenna radome Generally for shell structure. According to the spec...