RFID (radio frequency identification) reader based on adaptive smart antennae

Abstract

The invention discloses an RFID (radio frequency identification) reader based on adaptive smart antennae, belonging to the technical field of radio frequency identification. The RFID reader comprises a protocol processing module, a digital beam former, a digital transmitting / receiving component (T / R) component) and an antenna array consisting of a plurality of antenna elements, wherein the protocol processing module comprises coding, decoding and protocol processing; the digital beam former comprises an optimal weight generating network and an adaptive beam forming network; and the T / R component comprises a DDS (direct digital synthesizer), an upper frequency converter, a lower frequency converter, a filter, a power amplifier, a circulator and an A / D (analog-to-digital) sampling unit. The RFID reader disclosed by the invention can ensure that antenna beam main lobes point to a useful signal direction and null or lower side lobes point to an interference signal direction, so that the identification range of the reader is expanded and the interference resistance of the reader is improved.

Description

technical field [0001] The invention relates to a radio frequency identification (RFID) technology, in particular to an RFID reader. Background technique [0002] With the development of information technology, the Internet of Things has developed into a new industry. As one of the foundations of the Internet of Things, Radio Frequency Identification (RFID) technology has become a technology that people pay more and more attention to. The RFID system is mainly composed of three parts: transponder (radio frequency card and electronic tag), reader (reader and base station) and host computer system (middleware and network application). In the radio frequency identification system, according to the different structures of the electronic tag power supply system, RFID electronic tags are mainly divided into active tags, semi-active tags and passive tags. Active tags and semi-active tags have an external battery, which provides energy for the work of the tag chip. The advantage is...

AI Technical Summary

Problems solved by technology

[0004] (1) In the passive UHF RFID system, the maximum recognition distance of a reader is about 10 meters, and the total effective recognition area is limited, which cannot meet the needs of most users

[0005] (2) In the UHF RFID system, a key problem is that it is difficult to achieve 100% recognition rate, that is, some tags are not recognized, that is, the problem of missing tags

In terms of hardware, there are two main reasons for the problem of lost tags: First, the effective identification area of ​​passive RFID systems is limited because of the limited transmit power of the antenna and the fixed radiation pattern

Second, multipath interference causes some tags not to have enough energy to be activated in the identification area

[0007] (4) Since the commonly used RFID reader antenna has a low-gain, wide-beam transmission pattern, the label positioning error is relatively large

If a high-gain, multi-beam scanning antenna is used, the EIRP can exceed 4W in a certain direction for a short period of time. When calculating the average power, it has the same average power as a low-directivity, fixed-beam antenna because the beams are in multiple direction is controlled by sweeping, which reduces the average power

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