RF Low Noise Amplifier Circuit Principle
Radio frequency refers specifically to electromagnetic waves that have a certain wavelength that can be used for radio communications. The high-frequency circuit used to generate the radio frequency becomes a radio frequency circuit, which basically consists of passive components, active devices, and passive networks. With the development of communication technology, the frequencies used by communication devices have been increasing. Radio frequency (RF) and microwave (MW) circuits are widely used in communication systems. The field of RF circuit design has received special attention from the industry.
RF (Radio Frequency) technology is widely used in various fields, such as: television, radio, mobile phones, radar, automatic identification systems. The special term RFID (Radio Frequency Identification) refers to the use of radio frequency identification signals to identify objects. Applications of RFID include: ETC (Electronic Toll Collection), railway locomotive and vehicle identification and tracking, container identification, identification, certification and tracking of valuables, commercial retail, medical care, logistics, etc. Target management, outbound management, and animal identification , tracking, automatic locking of the vehicle (anti-theft)
RF (radio frequency) refers specifically to electromagnetic waves that have a certain wavelength that can be used for radio communications. Electromagnetic waves can be expressed by their frequency as: KHz (kHz), MHz (megahertz), and GHz (gigahertz). Its frequency range is VLF (very low frequency) ie 10-30 KHz to EHF (very high frequency) ie 30-300 GHz. RFID is a flexible application technology that is easy to operate, simple and practical, and particularly suitable for automation control. Its unique advantages are beyond other identification technologies. It can support both read-only and read-write work modes without contact or aiming; it can work freely in various harsh environments; and it can perform high-level data integration. In addition, because this technology is difficult to be counterfeited and invaded, RFID has extremely high security protection capabilities.
Conceptually speaking, RFID is similar to bar code scanning. For bar code technology, it attaches an encoded bar code to an object and uses a dedicated scanning reader to transmit information from bar magnetic to scan and write using optical signals. RFID, on the other hand, uses a dedicated RFID reader and a dedicated RFID unit that can be attached to the target, and uses RF signals to transmit information from the RFID unit to the RFID reader. The RFID unit contains all kinds of relevant information about the target, such as the name of the target, the starting point of the target transportation, the transit point, and the specific time when the target passes through a certain place. It can also be loaded such as temperature. And other indicators. RFID units, such as tags, cards, etc., can be flexibly attached to various types of items from the vehicle to the cargo chassis. The radio frequency used by the RFID technology is 50 KHz-5.8 GHz. As shown in FIG. 1, a basic RFID system generally includes the following: Several parts:
An RFID unit (answering machine or card, tag, etc.) carrying information about the target; an antenna for transmitting RF signals between readers and RFID units; an RF transceiver for generating RF signals; The RFID reader returns the RF signal and transmits the decoded data to the host system for processing. The antenna, reader, transceiver, and host can be partially or fully integrated into a single unit or integrated into a small number of components. Different manufacturers have their own different integration methods.