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,...

How to systematically implement advanced antenna architecture for LTE wireless devices Expect to finish reading in 13 minutes With the substantial improvement of its connection reliability and transmission speed, LTE is rapidly developing all over the world. According to data from the Global Mobile Suppliers Association (GSA), more than 318 LTE networks have been put into commercial use in 111 countries and regions. There is a commonality in all of these LTE networks that have been commercialized and are being planned. They also need to realize the multiple input and multiple output (MIMO) requirements of LTE. These MIMO requirements will extend to base stations and terminal equipment. In the case of terminal equipment, there are several reasons that make MIMO a challenge, including the need for multiple antennas, the trend of continuous thinning, unprecedented frequency band separation, operator preference for low frequencies, and lack of experience in RF design. 3G requires only one antenna, while MIMO technology requires at least two antennas. The number of antennas will increase as MIMO is designed to be 4×4 and 8×8. With multiple LTE antennas (including 3G/2G backup antennas, GPS, Wi-Fi, Bluetooth, and NFC), finding space becomes more difficult. The high-end MIMO design conflicts with thinner and lighter devices. As devices become thinner and lighter, the internal space of smartphones and tablets is declining at a rate of 25% per year. The display screen and battery received the highest priority, while components such as the processor, memory, antenna system, and other components could only compete for the remaining space. On the one hand, there is a trend toward thinner; on the other hand, MIMO and low frequency bands (such as 700MHz) require a larger physical size antenna configuration. To meet these two needs at the same time, this gives original equipment manufacturers (OEMs) and their The design team brings pressure that cannot be ignored. LTE operates in more than 40 frequency bands, covering from 450MHz to 2.7GHz, about half of which have been used in existing equipment. Establishing LTE global roaming for smartphones or tablets requires at least 40 frequency bands to be supported. In areas not covered by LTE, it is downgraded to the corresponding 3G standard. In these frequency bands, even in any small subset of frequency bands, it is challenging to find antenna space for the necessary 2×2 or more MIMO, plus antennas such as Wi-Fi and other technologies. It becomes even more difficult at times. Operators are always eager for lower capital expenditure (CapEx) and operating cost (OpEx), so low frequency bands become their best choice. The general experience is that lower frequency and lower density base stations will bring better revenue to operators. Lower frequency bands can also provide better indoor coverage, such as 700MHz. This frequency band can also meet the needs of the rapidly growing "Internet of Things" (IoT) market and pro...

Antenna principle Expect to finish reading in 9 minutes 1. Antenna principle 1.1 Definition of antenna: A device that can effectively radiate electromagnetic waves in a specific direction in space or can effectively receive electromagnetic waves from a specific direction in space. 1.2 The function of the antenna: Energy conversion-the conversion of guided traveling waves and free space waves; Directional radiation (receiving)-has a certain directionality. 1.3 Principle of antenna radiation 1.4 Antenna parameters Radiation parameters Half-power beam width, front-to-back ratio; Polarization mode, cross-polarization discrimination rate; Directivity coefficient, antenna gain; Main lobe, side lobe, side lobe suppression, zero point filling, beam downtilt... Circuit parameters Voltage standing wave ratio VSWR, reflection coefficient Γ, return loss RL; Input impedance Zin, transmission loss TL; Isolation degree Iso; Passive third-order intermodulation PIM3… Antenna side lobe Horizontal beam width Front-to-back ratio: specify the ratio of the forward radiation power to the antenna and the backward radiation power within ±30° 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; Several key points of antenna gain: The 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. The gain of the antenna is produced by the superposition of the elements. The higher the gain, the longer the antenna length. The gain is increased by 3dB and the volume is doubled. The higher the antenna gain, the better the directivity, the more concentrated the energy, and the narrower the lobe. 1.5 Radiation parameters Polarization: Refers to the trajectory or changing state of the electric field vector in space. 1.6 Circuit parameters Return loss In this example, the return loss is 10log(10/0.5) = 13dB VSWR (Standing Wave Ratio) is another measure of this phenomenon Isolation: It is the ratio of the signal received by one polarization of the other polarization https://www.whwireless.com/

Aquatic Black Technology-IoT Hub's aquaculture intelligent monitoring system solution    The aquaculture industry is very strict in terms of environmental data requirements and sensitivity, and needs to pay attention to various data at all times. With the development of industrial Internet, Internet of Things, cloud computing and other technologies, the aquaculture industry can use these technologies to master various equipment data in real time, greatly improve the efficiency of the aquaculture industry's production, management, and service links, and accelerate the entire industry Upgrade and transformation of the chain. Project Background    A large aquaculture enterprise has several fisheries scattered across the country, and each fishery has one or more breeding equipment (controlled by PLC). However, existing equipment cannot upload status information in time and return it to the service center of the enterprise, resulting in poor controllability of the production process; water quality information cannot be updated in real time, resulting in increased production costs; equipment cannot be remotely controlled, resulting in high labor costs. The client hopes to establish a set of real-time monitoring system, which can upload on-site information in real time and grasp the situation in time.    aquaculture system monitoring solution based on IoT Hub    The IoT Hub Industrial Internet Empowerment Platform team designed an intelligent monitoring system for aquaculture based on customer pain points.   Equipment monitoring system architecture diagram The entire system IoT Hub industrial Internet empowerment platform, connected to the PLC of the aquaculture plant through the edge controller, transmits the field data to each local IoT Hub? server via WIFI or 4G, and finally each local IoT Hub uploads the data to the IoT The Hub Industrial Internet Empowerment Platform summarizes.   1 Features of IoT Hub Industrial Internet Empowerment Platform   ■ Provide powerful data storage capabilities   ■ Provide rich background service functions   ■ Provide flexible deployment methods   ■ Provide secure data protection   2 Features of Edge Controller   ■ Quick access to equipment   ■ Fast data analysis   ■ Results are uploaded quickly   ■ Remote control: You can remotely control the work of key equipment through mobile phones and tablets, requiring specific permissions.   ■ Timing trigger: The equipment can be controlled regularly through the management system and requires specific permissions.   ■ Real-time monitoring and alarm: real-time monitoring of various key data, when the parameter value reaches a dangerous value, the system sends a mobile phone text message to the manager.   ■...