About 5G antenna OTA test method analysis and application Estimated 8 minutes to finish reading www.whwireless.com Test methods of existing antennas With the deepening of electromagnetic research and the development of electronic technology, the development and application of antennas have penetrated into many fields such as navigation, communication, electronic countermeasures and radar, etc. Multi-beam antennas can form multiple mutually independent transmit or receive beams simultaneously or in time through phased arrays to achieve flexible control of beam shape and rapid switching of beam direction. At present, the most widely used phased array antenna test methods are mainly three: far-field method, near-field method and tight field method. 1、Far field test scheme Far-field test is the most direct test method, when the test distance is far enough, the human wave in the receiving surface is close to the plane wave. The diagram below shows the far-field test system, where the part under test can be rotated 360° in the vertical and horizontal planes, and the test probe position is fixed and can be polarised and rotated. The test system can test the beam assignment directional map and EIRP (Effective Isotropic Radiated Power), EVM (Error Vector Magnitude), occupied bandwidth, EIS (Effective Isotropic Sensitive), and EIS (Effective Isotropic Sensitive) of the 5G base station antenna. Isotropic Sensitive, effective omnidirectional sensitivity) and other RF radiation indicators. 2、Tight field test programme The tight field test is a far-field test method, which can use a reflector or lens to convert the spherical wave from the feed source at the focal point into a plane wave, so as to achieve the far-field test in a limited physical space. The figure below shows a parabolic single reflector constrained field test system that can test the beam assignment direction map and EIRP, EVM, occupied bandwidth, ACLR (Adjacent Channel LeakagePower ration), EIS, ACS (Adjacent Channel Selectivity) of a 5G base station antenna. Channel Selectivity) and other RF radiation indicators. 3、Near-field test solution Multi-probe spherical near-field test solution Near-field test in the measured antenna radiation near-field area to collect the amplitude and phase information, and then through the near and far field conversion algorithm to collect data into the far field direction map. The multi-probe spherical near-field test system is shown in the diagram below, where a large number of probes are arranged along the circumference of the radiated near-field of the DUT, and the DUT only needs to be rotated by 180 degrees to capture data from the entire radiated sphere. The system is capable of testing the beam assignment direction of a 5G base station antenna in CW (Continuous Wave) mode.   Single probe near-field test system Single probe near-field testing is less efficient than multi-probe spherical near-field testing, but it is simpler and requires less space. The ...

Principles and functions of common antennas and passive components that engineers must master Estimated 6 minutes to finish reading www.whwireless.com 1. Antenna principle 1.1 Definition of antenna: Ø A device that can effectively radiate electromagnetic waves to a specific direction in space or can effectively receive electromagnetic waves from a specific direction in space. 1.2 The function of the antenna: Ø Energy conversion-the conversion between guided traveling waves and free space waves; Ø Directional radiation (receiving)-has a certain directionality. 1.3 Principle of antenna radiation 1.4 Antenna parameters u Radiation parameters ØHalf power beam width, front-to-back ratio; ØPolarization method, cross-polarization discrimination rate; ØDirectivity coefficient, antenna gain; ØMain lobe, side lobe, side lobe suppression, zero point filling, beam downtilt... u circuit parameters ØVoltage standing wave ratio VSWR, reflection coefficient Γ, return loss RL; ØInput impedance Zin, transmission loss TL; Ø Isolation degree Iso; ØPassive third-order intermodulation PIM3… u antenna side lobe u Horizontal beam width u Front-to-back ratio: Specify the ratio of the forward radiation power to the antenna and the backward radiation power within ±30° u The relationship between gain and antenna size and beam width Flatten the "tire", the more concentrated the signal, the higher the gain, the larger the antenna size, and the narrower the beam width; u Several key points of antenna gain: ØThe antenna is a passive device and cannot generate energy. Antenna gain is just the ability to effectively concentrate energy to radiate or receive electromagnetic waves in a specific direction. Ø The gain of the antenna is produced by the superposition of the vibrator. The higher the gain, the longer the antenna length. The gain is increased by 3dB and the volume is doubled. ØThe higher the antenna gain, the better the directivity, the more concentrated the energy, and the narrower the lobe. 1.5 Radiation parameters u Polarization: Refers to the trajectory or changing state of the electric field vector in space. 1.6 Circuit parameters u return loss In this example, the return loss is 10log(10/0.5) = 13dB VSWR (Standing Wave Ratio) is another measure of this phenomenon u Isolation: It is the ratio of the signal received by a certain polarization of another polarization u Passive Intermodulation (PIM): When two frequencies f1 and f2 are input to the antenna, due to the nonlinear effect, the signal radiated by the antenna includes other frequencies in addition to frequencies f1 and f2, such as 2f1-f2 and 2f2-f1 (3rd order).

What does antenna interface mean? Estimated 2 minutes to finish reading You will often see the word antenna at the interface of some home electronic devices, this word actually means antenna, so its corresponding interface is actually the antenna interface, which is specifically used to connect the antenna port. antenna interface is a round antenna interface, antenna interface is an interface end of wireless devices, the antenna of the wireless device itself has a certain distance limit. When the distance beyond this limit, it is necessary to enhance the wireless signal through these external antennas to achieve the purpose of extending the transmission distance. There are three concepts involved. First, the frequency range it refers to the antenna work frequency band, this parameter determines which wireless standard it applies to wireless devices. Second, the gain value of this parameter indicates the antenna power amplification, the larger the value indicates that the signal amplification is larger, that is to say, when the gain value is larger, the stronger the signal, the better the transmission quality. Third, the antenna interface is mainly for wireless equipment that can be disassembled and external antenna, for different interfaces to correctly match the corresponding antenna, to increase the signal and extend the distance of the function. www.whwireless.com

Demystifying the antenna tuning of mobile 5G devices 2020-10-30 12:34 It is expected to finish reading in 5 minutes Want to design multiple mobile antennas? Facing the problem of reduced efficiency? Here is a guide to help you develop products with excellent antenna performance using COFF capacitor devices to improve system efficiency and expand coverage. 5G technology has led to a significant increase in the number of new frequency bands that mobile antennas must support. Due to the complexity of the design of new mobile phones, mobile phone designers need to use more and more aperture tuners on a single antenna. Increasing the aperture tuner helps to optimize the overall antenna performance of each frequency band, but sometimes at the expense of antenna efficiency. If the antenna efficiency and the performance of each frequency band of the antenna are not balanced, the performance and coverage of the entire device will be affected. Each antenna has an inherent resonant frequency at which the maximum antenna efficiency can be achieved. Place a parallel capacitor (to reduce the resonant frequency) or a parallel inductor (to increase the resonant frequency) on the antenna to achieve aperture tuning. Using multiple capacitors and inductors, the antenna can be tuned to multiple frequencies through the antenna tuner switch, as shown in the figure below. Interpretation of RON and COFF Aperture tuning mainly uses tuner switches and tunable capacitors. The main quality factors of these switches are on-state resistance (RON) and off-state capacitance (COFF), as shown in the figure below. For tunable capacitors, it is important to have a wide range of tuning capacitors and a good Q factor (quality factor). RON and COFF will significantly affect the antenna efficiency. When the voltage is low, the influence of RON is greater; when the voltage is high, the influence of COFF is greater; the switch layout strategy of low RON or low COFF can be optimized for different frequencies. In the off state, the COFF of the aperture tuner will affect the capacitive load on the antenna, thereby reducing the resonant frequency. The higher the COFF of the tuner, the greater the deviation of the freque ncy from the natural resonance frequency of the antenna. To Figure 1 below shows the effect of COFF of a single pole double throw (SPDT) switch on the simulation efficiency of an inverted F antenna (IFA). The reference measurement value shown is taken when the SPDT is not placed in the tuning position. After SPDT is added, the COFF of each port is set to 100 fF and 200 fF respectively. figure 1. COFF antenna tuning When switching from the reference antenna to the low COFF switch, a frequency shift of 40 MHz is observed, and the peak efficiency drops by 0.3 dB. When switching from a low 100fF COFF to a high 200fF COFF switch, a 40 MHz offset will also occur, and the peak efficiency will drop by 0.85 dB. Compared with the benchmark, a frequency shift of 80 MHz finally occurred,...