Detailed analysis of the 8 core parameters of antennas 2021-11-26 www.whwireless.com Estimated 6 minutes to finish reading Antennas have always been the key focus of attention in the field of connectivity products, we have previously carried out a preliminary introduction and analysis according to the type of antenna, but in this large segment of the antenna, it is necessary to know further its key parameters in order to understand more deeply the advantages and use of each type of antenna. The following parameters are divided into two main parts: radiation parameters and circuit parameters, which we will analyse precisely and quickly introduce the meaning of them. Front-to-back ratio The antenna's front-to-back ratio is the ratio of the power flux density in the maximum radiation direction of the main flap (specified as 0°) to the maximum power flux density near the opposite direction (specified as within 180°±30°) F/B=10log(front-to-back power/backward power). Electric down tilt angle The electric down tilt angle is the maximum radiation pointing on the vertical radiation surface of the communication antenna and the angle of the antenna normal. Communication antenna is divided into fixed down tilt antenna and electric tilt antenna according to whether it supports electric down tilt adjustment: fixed down tilt antenna refers to the fixed down tilt antenna generated by the amplitude and phase assignment of the antenna radiation unit array according to the wireless coverage demand; and electric tilt antenna refers to the phase difference of different radiation units in the array through phase shifting unit to produce different radiation main flap down tilt state, usually the down tilt state of electric tilt antenna Only within a certain adjustable angle range. Wave speed width In the direction of the diagram usually have two flaps or more flaps, which is the largest flap called the main flap, the rest of the flap called the secondary flap. The angle between the two half-power points of the main flap is defined as the width of the flap of the antenna directional diagram. Called half power (angle) flap width. The narrower the main flap flap width, the better the direction, the stronger the anti-interference ability. Generally speaking, the narrower the main flap beam width of the antenna, the higher the antenna gain. Antenna gain Gain and antenna size and beam width of the relationship. The flatter the "tyre", the more concentrated the signal, the higher the gain, the larger the antenna size, the narrower the beamwidth. → 3 important points to pay attention to in particular 1. Antennas are passive devices and do not generate energy. Antenna gain is only the ability to focus energy effectively in a particular direction to radiate or receive electromagnetic waves. 2, the gain of the antenna is generated by the superposition of oscillators. The higher the gain, the longer the length of the antenna. Gain increase 3dB, double the volume. 3, the higher th...

Antenna gain calculation 2021-10-22 www.whwireless.com Estimated 6minutes to finish reading Antenna gain is a very important part of the antenna knowledge structure, of course, is also one of the important parameters for the selection of antennas. Antenna gain for the quality of operation of the communication system also plays a big role, in general, the gain is mainly dependent on reducing the width of the vertical-oriented radiation flap, and in the horizontal plane to maintain the omnidirectional radiation performance. A, the definition of antenna gain. Antenna in a certain direction of the radiation power flux density and reference antenna in the same input power when the maximum radiation power flux density ratio. → Need to pay attention to the following points. (1) if not specially marked, antenna gain are referred to the maximum radiation direction gain. (2) Under the same conditions, the higher the gain, the better the directionality, the farther the wave propagates, i.e. the distance covered increases. However, the wave speed width will not be compressed, the narrower the wave flap, thus leading to poor uniformity of coverage. (3) Antennas are passive devices and do not generate energy. Antenna gain is only the ability to effectively concentrate energy to a particular direction of radiation or receive electromagnetic waves. Second, the formula for calculating antenna gain We can learn from the definition of antenna gain, antenna gain and antenna directional map has a close relationship, the narrower the main flap, the smaller the secondary flap, the higher the gain. 5G 4G 8dbi mimo antenna (1) For parabolic antenna, the gain can be approximated by the following equation. G(dBi) = 10Lg{4.5×(D/λ0)^2} *Note that D: paraboloidal diameter λ0: central operating wavelength 4.5: Statistically validated empirical data 2.4 GHz 13 dBi bipolar omnidirectional MIMO antenna - N-type female connector (2) For an upright omnidirectional antenna, the following equation can also be used to approximate G(dBi) = 10Lg{2L/λ0} *Note that L: Antenna length λ0: central working wavelength Third, gain and transmitting power The RF signal output from the radio transmitter, through the feeder (cable) to the antenna, by the antenna in the form of electromagnetic wave radiation out. After the electromagnetic wave reaches the receiving place, it is received by the antenna (only a very small part of the power is received) and sent to the radio receiver through the feeder. In the engineering of wireless networks it is therefore very important to calculate the transmitting power of the transmitter and the radiation capacity of the antenna. The transmitted power of a radio wave is the energy in a given frequency band range and is usually measured or measured in two ways. Power (W): a linear level relative to 1 watt (Watts). Gain (dBm): a proportional level relative to 1 milliwatt (Milliwatt). → The two expressions can be converted to each other. dBm = 10 x log[power mW] mW ...

Antenna technology in mobile communications 2021-10-11 www.whwireless.com Estimated 10 minutes to finish reading The antenna is an indispensable component of mobile communication and plays a very important role, it is located between the transceiver and the electromagnetic wave propagation space and achieves an effective energy transfer between the two. By designing the radiation characteristics of the antenna, the spatial distribution of electromagnetic energy can be controlled to improve resource utilisation and optimise network quality. Especially in the development of 3G, Smart Antenna has become a hot spot in recent international mobile communication research.     A, mobile antenna using the key technology     ⒈ symmetric oscillator and antenna array     The antenna form used in the current mobile communication is mainly line antenna, that is, the length of the antenna radiation body l is much larger than its diameter d line antenna is based on symmetrical oscillator. When the wavelength determined by the frequency change of the high-frequency current through the wire is much greater than the length of the wire, it can be considered that the amplitude and phase of the current on the wire is the same, only its value with time t for sinusoidal changes, this short wire is called current element or Hertzian dipole, it can be used as an independent antenna or become a complex antenna component unit. Complex antenna electromagnetic field in space can be seen as the result of the iterative addition of electromagnetic fields generated by many current elements. The radiated power of a current element is the average of the electromagnetic energy radiated outwards through the sphere per unit time. The energy of the radiated field will no longer be returned to the wave source, so it is an energy loss for the source. Introducing the concept of a circuit, we use the equivalent resistance to express this part of the radiated power, then this resistance is called the radiation resistance, the radiation resistance of the current element is :                         RΣ = 80π2(l/λ)2(l)     The directional diagram of the current element can be obtained by integrating the calculation. When l/λ < 0.5, as l/λ increases, the directional map becomes sharp and has only the main flap, which is perpendicular to the oscillator axis; when l/λ > 0.5, a secondary flap appears, and as l/λ increases, the original secondary flap gradually becomes the main flap, while the original main flap becomes the secondary flap; when l/λ = 1, the main flap disappears. This change in directionality is mainly caused by the change in current distribution on the oscillator.     Multiple symmetrical oscillators combined to form the antenna array. According to the symmetrical oscillator arrangeme...

How do antennas actually work? 2021-9-16 www.whwireless.com Estimated 8 minutes to finish reading Antennas are widely used in telecommunications, for example in radio communications, radio and television. Antennas pick up electromagnetic waves and convert them into electrical signals, or pick up electrical signals and radiate them as electromagnetic waves. In this article, let's take a look at the science behind antennas. If we have an electrical signal, how do we convert it into an electromagnetic wave? You probably have a simple answer in mind: that is to use a closed wire which, with the help of the principle of electromagnetic induction, will be able to generate a fluctuating magnetic field and an electric field around it. However, this fluctuating field around the source is of no use in the transmission of the signal. Here the electromagnetic field does not propagate, it just fluctuates. In an antenna, the electromagnetic waves around the source need to be separated from the source and they should propagate. Before we look at how to make an antenna, let's understand the physics of an antenna. Wave separation considers the placement of a positive charge and a negative charge. This pair of charges arranged very close together is called a dipole, and they obviously produce an electric field as shown in the diagram. Assuming that these charges are as shown, oscillating at the midpoint of their path, the velocity will reach a maximum and at the end of their path, the velocity will be zero, and due to the change in velocity, the charged particles will experience successive accelerations and decelerations. The challenge now is to find out how to make the electromagnetic field vary due to this motion. Let us focus on just one electric field line that expands and deforms in front of the wave that forms at time zero, after a time period of one-eighth. As shown in the diagram. You may be surprised to expect a simple electric field to be shown at this location as shown below. Why does the electric field expand to form an electric field like this one? It is because accelerating or decelerating charges produce some electric field memory effect and the old electric field does not easily adapt to the new electric field. It will take us some time to understand this memory effect electric field or the accelerating or decelerating charges produced by the kink. We will discuss this interesting topic in more detail in another article. If we continue the analysis in the same way, we can see that in a quarter time period the wave front meets at a point where. After this, the wave fronts separate and propagate. Note that this changing electric field automatically generates a magnetic field perpendicular to his change. If you plot the variation of the electric field strength with distance, you can see that the wave propagation is intrinsically sinusoidal. It is interesting to note that the resulting propagation wavelength is exactly twice the length of the dipole. T...