Under the trend of Internet of Everything, wireless communication module has become an indispensable part of various electronic devices, and the communication quality of the module largely depends on whether the antenna design is reasonable or not. This paper describes how to choose the right antenna and play the best performance of the antenna.
With the progress of technology, in order to save the development cycle, many manufacturers have introduced a variety of finished antennas. However, if engineers do not choose the right antenna, it will not only fail to achieve the desired effect, but also waste a lot of time and cost on debugging, which is not worth the loss. In this article, I will introduce several commonly used antennas and combine them with the actual use of experience in the project to give design suggestions for your reference.
Next, I will introduce the commonly used antenna types.
(1) On-board PCB type antenna: low cost using PC etching, but limited performance, good tunability. WiFi wireless communication module.
(2) T-Patch type : Commonly used ceramic antenna, small footprint, high integration, easy to replace, suitable for space
products with small space requirements, but this type of antenna is slightly more expensive and has a smaller bandwidth.
(3) External rod antenna: good performance, no need to debug, easy to replace, high gain, applicable to a variety of terminal equipment.
(4) FPC antenna: connected by feed line, free installation, high gain, machine non-metallic metal can usually be backed with adhesive paste
The shell is suitable for products with high performance requirements and sufficient shell space.
The role of the antenna is to radiate RF signals into free space. At this point, choosing the right antenna has a great impact on the transmission distance. The antenna is very sensitive to the surrounding environment, even if you choose the right antenna, it will not achieve the expected results. Since some customers do not know the factors that need to be considered for antenna design, we give some experiences in the actual engineering design, so that customers can better design their own circuits and PCBs to increase the chance of project success.
1、 Matching circuit design
When designing the schematic diagram, you need to reserve a π-type network in the antenna and module RF output pins. Antenna impedance is affected
PCB laying, antenna installation, surrounding metal and other factors, in order to match the antenna to 50 when it is seriously off 50 when the impedance of the ohms. x1, x2, x3 If the antenna is standard, they are all reactive elements 50 ohm impedance, so X2, X3 can not be soldered, X1 connected to the 220PF capacitor or 0 ohm resistor. In the PCB design process, these three devices are located as close as possible to the RF output pins of the module, with short, straight transmission lines. Matching components around 1.5mm in order to reduce the impact of parasitic parameters on the matching circuit, do not influence in the circuit.
2, microstrip line design
In the PCB in the design, antenna and module output impedance is mostly 50 ohms, in order to reduce the transmission process of energy reflection, RF output pin and antenna between PCB leads should be 50 ohms microstrip line. Commonly used plate is FR4 (dielectric constant 4.2-4.6), according to experience, when the line width of the microstrip line distance from the reference layer of 2.2 times the distance, the characteristic impedance of the microstrip line is about 50 ohms. It is recommended to use the microstrip line impedance control tool (ADS, txline, etc.) to calculate the specific design, and complete the design of the microstrip line through the actual debugging. As shown in the figure below, the grounding layer under the microstrip line must be a complete ground, and more grounding holes are needed on both sides of the microstrip line.
3. The effect of metal on the antenna
If there is metal material near the antenna, the metal can reflect electromagnetic waves, which will not only affect the actual space of the antenna, increase the loss resistance of the antenna, reduce the radiation efficiency, but also deteriorate the radiation performance of the antenna. Attention should be paid when installing the antenna:
a: The antenna should be at least 5mm from the battery;
b: The antenna should be at least 4mm from the shielding shell;
c: In the case of the need to install the shell, do not paint or coat the surface components of the shell.
Ltd. specializes in high-precision GNSS modules and wireless communication products, technology development and application promotion service providers, relying on the wireless communication technology in the field of R & D and promotion experience, JUNODA set up a team with a wealth of experience in hardware and software development technology, aimed at domestic and foreign OEM / ODM customers and system integrators to provide high-quality, high-performance wireless module and application We aim to provide high-quality, high-performance wireless modules and application programs to OEM/ODM customers and system integrators at home and abroad, and create long-term value for customers!
The company mainly provides integrated antenna module, dual-frequency high-precision module, single-frequency high-precision module, thousand-seeking high-precision module, Zhongke micro-positioning module, U-BLOX positioning module, SICOM communication module, inertial navigation DR module, UWM GNSS module, RTK differential module, 4G communication module and high-precision antenna, etc., the products are sold well in Beijing, Shanghai, Shenzhen, Guangdong, Jiangsu, Zhejiang, Sichuan, Hunan and other parts of the country. Our GNSS modules are widely used in many application fields, such as drones, vehicle security monitoring and dispatching, automatic bus stop announcement, DVR, car DVD navigation, GPS electronic dog, synchronized timing, high-altitude balloon monitoring, engineering machinery, industrial automation, etc. In the field of wireless communication products, the company is closely involved in the field of wireless communication, such as RTK, RTK differential module, 4G communication module and high-precision antenna.
In the field of wireless communication products, the company follows the latest development of international communication technology, introduces and acts as an agent for wireless communication modules that meet the market demand, and the products have a comprehensive layout from 2G, 3G, 4G, and are widely used in financial electronic payment, vehicle remote control, remote advertising information, repeater monitoring, mobile Internet terminals, smart home, remote medical care, network testing, enterprise information management, anti-theft alarm, Remote video transmission, intelligent meter reading, mobile computing, network navigation, voice phone, wireless gateway and other fields. Focus areas include video surveillance, network optimization, routers, POS and other M2M industry applications.
If you need to consult, please contact online customer service!
