CN213425179U - Antenna device on high-frequency RFID chip - Google Patents

Abstract

The passive high-frequency chip needs to connect the external antenna with a welding Point (PAD) on the top of the chip through a welding technology. The external antenna needs to be manufactured through a special process technology, and is high in cost and large in antenna area. The welding technology also has disadvantages, such as tedious process, high cost, and large influence of coupling capacitance generated when welding chips on the performance and consistency of the high frequency tag. The utility model provides an antenna device on high frequency RFID chip, the purpose is in order to reduce its manufacturing cost, makes its range of application more extensive, produces the high frequency electronic tags who has more competitiveness.

Description

Antenna device on high-frequency RFID chip

Technical Field

The utility model belongs to the technical field of integrated circuit, specifically, belong to the design field of high frequency RFID chip.

Background

RFID refers to radio frequency identification, which is a communication technology that can identify a specific target and read and write related data through a radio signal without establishing physical or optical contact between an identification system and the specific target. The RFID can be used as a unique identity card of each object, and is also a basis for identifying, communicating and interconnecting each object in the Internet of things. In recent years, with the development of technologies such as large-scale integrated circuits, network communication, and information security, the RFID technology is in a commercial application stage. Due to the characteristics of high-speed moving object identification, multi-label simultaneous identification, non-contact identification and the like, the RFID technology shows great development potential and application space. The application fields of the RFID are as follows: logistics, retail, anti-counterfeiting, transportation, identification card identification, medical, food, automotive, and the like.

The working frequency is an important technical index of the RFID, and the frequency band of the RFID is internationally recognized and divided: low frequency, high frequency, ultra high frequency, microwave. The high-frequency RFID is the most mature application at present, belongs to passive RFID, the working energy of the high-frequency RFID is derived from inductive coupling between a reader coil and a high-frequency tag coil, the radio frequency working frequency of the high-frequency RFID is generally 3MHz to 30MHz, and the most typical working frequency of the high-frequency RFID is 13.56 MHz.

The high frequency RFID has the following characteristics: the transmission speed is high, generally more than 100kbps, and multiple tags can be identified; the frequency band system is mature, and the price of the read-write equipment is low; the storage capacity of the high-frequency tag is from 128 bits to more than 8K bytes, the high-frequency tag can support high safety characteristics, and the high-frequency tag is integrated from the simplest write locking to stream encryption, even an encryption processor; fourth, the RFID technology is generally applied to RFID applications with high safety requirements, such as identity recognition, library management, product management and the like, and the largest application in the frequency band is a well-known non-contact smart card, such as a traffic card, an access card, a second-generation identity card and the like.

As shown in fig. 1, the passive high-frequency chip needs to connect the external antenna to the bonding PAD (PAD) on the top of the chip by using a bonding technique. The external antenna needs to be manufactured through a special process technology, and is high in cost and large in antenna area. The welding technology also has disadvantages, such as tedious process, high cost, and large influence of coupling capacitance generated when welding chips on the performance and consistency of the high frequency tag.

Disclosure of Invention

The utility model provides an antenna device on high frequency RFID chip, the purpose is in order to reduce its manufacturing cost, makes its range of application more extensive, produces the high frequency electronic tags who has more competitiveness.

The utility model relates to an antenna device on high frequency RFID chip is an on-chip inductance coupling antenna: the on-chip inductive coupling antenna is manufactured by a copper metal wire or an aluminum metal wire in a CMOS (complementary metal oxide semiconductor) process, and the antenna presents a specific and regular spiral surrounding pattern, such as a square or rectangular surrounding pattern; the inductive coupling antenna can use 1 layer of copper metal wire or aluminum metal wire in the CMOS process; the inductive coupling antenna can also use a plurality of layers of copper metal wires or aluminum metal wires in a CMOS process; the on-chip inductive coupling antenna and the chip internal voltage-stabilizing resonant capacitor form an oscillation loop together, the oscillation loop is tuned to the transmitting frequency of the reader-writer, and the voltage U on the inductive coupling antenna coil reaches the maximum value through the resonance of the loop.

The utility model discloses an antenna device, characterized in that, the antenna device can be manufactured through CMOS technology with the high-frequency chip and is an independent high-frequency electronic tag with a receiving and dispatching antenna after the CMOS technology is manufactured; the antenna device reduces the area of the high-frequency tag antenna to a millimeter level; the antenna device is not required to be connected with the chip and the antenna through a welding technology; the antenna device increases the performance and consistency of the high-frequency tag.

Drawings

Fig. 1 shows a passive high-frequency chip connected with an external antenna pattern by a welding technology.

Fig. 2 is a diagram of a complete high frequency RFID system.

Fig. 3 is a diagram of an antenna device on a high frequency RFID chip according to the present invention.

Detailed Description

The preferred embodiment is described in detail below with reference to fig. 2 and 3.

As shown in fig. 2, a complete high-frequency RFID system consists of a reader, a passive high-frequency electronic tag, and a data management system.

The reader is a device that reads information from the tag or writes information to be stored in the tag into the tag. The basic construction of a reader generally includes: the device comprises a receiving and transmitting antenna, a frequency generator, a phase-locked loop, a modulation circuit, a microprocessor, a memory, a demodulation circuit and an external interface.

The passive high-frequency electronic tag is composed of an external antenna and a high-frequency chip (a rectifying circuit, a demodulating circuit, a modulating circuit, a storage circuit and a logic control circuit), and is used for supplying power to the passive high-frequency electronic tag for a short time by receiving microwave signals transmitted by a reader-writer and acquiring energy through an electromagnetic induction coil, so that the information exchange is completed.

As shown in fig. 3, the utility model relates to an antenna device on high frequency RFID chip to chip internal circuit is the center, and PAD1 and PAD2 are two antenna connection points, with the copper metal line in the CMOS technology or the aluminium metal line with specific and regular spiral surround the figure (for example square or rectangle surround the figure), form on the piece inductance coupling antenna among the antenna device. When the on-chip inductive coupling antenna uses a plurality of layers of metal wires, such as copper wires or aluminum wires, the metal wires of the layers are connected in series or in parallel.

The LC resonance frequency calculation formula is as follows:

in the formula, F is the resonance frequency and the unit is MHz; l is the inductance value of the antenna coil and has the unit of uH; c is the internal steady voltage resonance electric capacity of chip, and the unit is pF.

For example, at 13.56MHz where a high frequency tag needs to operate, its metal line inductance value is 1uH, and the total required resonant capacitance is calculated by the formula to be 137.8 pF. And conversely, obtaining the internal voltage-stabilizing resonance capacitance value of the chip, and obtaining the inductance value of the on-chip inductive coupling antenna.

Although the present invention has been described in detail with respect to the preferred embodiments, various modifications and alterations will become apparent to those skilled in the art upon reading the foregoing description. The above description and drawings are only examples of the practice of the invention, and it should be understood that the above description should not be taken as limiting the invention.

Claims (1)

1. The utility model relates to an antenna device on high frequency RFID chip is an on-chip inductance coupling antenna: the on-chip inductive coupling antenna is manufactured by a copper metal wire or an aluminum metal wire in a CMOS (complementary metal oxide semiconductor) process, and the antenna is in a spiral surrounding square or rectangle shape; the inductive coupling antenna can use 1 layer of copper metal wire or aluminum metal wire in the CMOS process; the inductive coupling antenna can also use a plurality of layers of copper metal wires or aluminum metal wires in a CMOS process; the on-chip inductive coupling antenna and the chip internal voltage-stabilizing resonant capacitor form an oscillation loop together, the oscillation loop is tuned to the transmitting frequency of the reader-writer, and the voltage U on the inductive coupling antenna coil reaches the maximum value through the resonance of the loop.

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