Full-integration UHF-RFID reader-writer radio frequency reception front end circuit working in 860-960MHz

Abstract

The invention discloses a full-integration UHF-RFID reader-writer radio frequency reception front end circuit working in 860-960MHz, consisting of four-input cross coupled difference low noise amplifier LNA, an I path lower mixer DM1, a Q path lower mixer DM2, a I path low-pass filter LPF1, a Q path low-pass filter LPF2 and an orthogonal upper mixer, wherein the orthogonal upper mixer comprises an I path upper mixer UM1, a Q path upper mixer UM2 and a summator ADDER. The invention mixes carrier leakage and label signals downwardly to low frequency, and the label signals are removed through the low-pass filter to maintain direct current; the direct current is converted to a carrier frequency band through the upper mixer; the carrier frequency band and the label signal containing the carrier leakage go through the difference low noise amplifier, and the carrier leakage signal is offset and the label signal is amplified. In the 10 dBm carrier leakage situation, the conversion gain in the working frequency band of 860-960MHz is higher than 26dB, the noise coefficient is smaller than 24dB, the sensitivity is superior to -86dBm, the time consumed by the carrier for offset is smaller than 15Mus, and all requirements for communication speed of the UHF RFID are satisfied.

Description

technical field [0001] The invention belongs to the technical field of UHF RFID reader-writer integrated circuit design, and relates to a CMOS fully integrated UHF RFID reader-writer radio frequency receiving front-end circuit with a carrier leakage cancellation function and working at 860-960 MHz. Background technique [0002] In recent years, backscattered radio frequency systems have received extensive attention and research due to their low cost and high integration. The RFID system is one of the most famous applications. Due to its high flexibility and programmability, RFID technology is widely used in fields such as medicine, construction, security, transportation and military. UHF RFID is an automatic identification technology with a recognition distance of more than several meters. It has the advantages of fast, anti-interference, safety, and relatively long distance. It is considered to replace barcode technology in the near future. [0003] In the UHF RFID system...

AI Technical Summary

Problems solved by technology

[0004] In order to read passive tags, UHF RFID requires the reader to emit continuous carrier waves to provide energy for the tags, and the tag backscatter modulates its stored data, so that there is a high carrier leakage (10dBm) in the RF front end of the receiver in the read mode; due to and The expected signal frequency is very close (40-600kHz), and the in-band carrier leakage is difficult to filter out, which severely limits the sensitivity of the RFID reader chip

In addition, the carrier leakage will reduce the gain of the receiver or even directly saturate it, and the reader cannot work normally

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