CN201303048Y - Microwave range dielectric resonator RFID tag antenna capable of working on metal surfaces - Google Patents

Abstract

The utility model discloses a microwave section dielectric resonance RFID tag antenna which can work on metal surfaces, comprising an upper high dielectric constant dielectric resonator (1), a lower dielectric substrate (2); an upper high dielectric constant dielectric resonator (1) and Between the lower dielectric substrates (2) is a microstrip feeder (4); the lower surface of the lower dielectric substrate (2) is pasted with a copper floor (3); between the microstrip feeder (4) and the copper floor (3) An input port (5) of the antenna is arranged between them, and is directly connected with the RFID tag chip. The utility model can work in the microwave frequency band, that is, in the radio frequency identification system of 2.45GHz or 5.8GHz, and the bandwidth covers 2400MHz-2483MHz or 5725MHz-5875MHz. Not only can it work on non-metallic surfaces, but it can also be conveniently applied to metal surfaces. It has the characteristics of high gain, small size, simple structure, easy processing and low cost.

Description

Microwave Dielectric Resonance RFID Tag Antenna Can Work on Metal Surface

technical field

The utility model relates to a radio frequency identification electronic label antenna, in particular to a high-gain radio frequency identification electronic label antenna which can be applied in the microwave frequency band, that is, in the range of 2400MHz-2483MHz or 5725MHz-5875MHz, and can be conveniently applied to metal surfaces.

Background technique

Radio Frequency Identification (RFID) technology is an automatic identification technology that conducts non-contact two-way data communication through radio frequency to identify targets and obtain relevant information. Radio frequency identification technology (RFID) has been rapidly promoted in recent years, and is widely used in logistics, warehouses and other occasions for item identification, helping such industries to collect and manage item information in an informatized and high-speed manner, so as to achieve high efficiency of items management and scheduling. The radio frequency identification system is mainly composed of three parts: the reader, the middleware and the electronic tag. The electronic tag is composed of an on-chip antenna and an integrated chip. It exchanges data with the reader through electromagnetic waves, and has intelligent reading and writing and encrypted communication functions. The antenna transmits and receives the power of the front-end radio frequency signal in the form of electromagnetic waves. It is an interface device between the circuit and the space, and is used to realize the conversion of guided wave and free space wave energy. In the RFID system, the electronic tag antenna is responsible for receiving energy and plays a key role in the entire RFID system.

However, there are two major difficulties in the design and application of microwave segment RFID tag antennas. First, RFID tags will be pasted on the surface of various items with different dielectric properties in practical applications. Different dielectric properties of items will degrade the performance of RFID tag antennas to varying degrees. In particular, the performance deterioration caused by metal items is particularly serious, which will cause the RFID tag to be unrecognizable and reduce the success rate of the RFID system for identifying items. However, the traditional flexible plate antenna cannot work on the metal surface, which requires the design of an antenna RFID tag antenna that can work on the metal surface. Second, due to the complexity of the environment, the reading distance of the electronic tag is reduced. In order to increase the effective reading distance of the electronic tag, it is necessary to increase the gain of the tag antenna in order to meet the above requirements. Although the currently used microstrip antenna can work on metal surfaces, the gain of the antenna is low, and its reading distance is relatively short. Therefore, it is necessary to design an antenna with higher gain to meet actual needs.

In the design of the RFID tag antenna, in addition to considering and overcoming the above two difficulties, it is also necessary to make the RFID tag antenna have the characteristics of convenient input impedance adjustment, small size, easy processing and low cost. Only such a tag antenna can be accepted by the market and bring convenience to the popularization and use of RFID technology. The dielectric resonant antenna is designed directly considering its grounding characteristics, which is less affected by the floor, and has the characteristics of high radiation efficiency and high gain.

Utility model content

The purpose of the utility model is to provide a microwave segment RFID electronic tag antenna which can be conveniently applied to the metal surface, has high gain, small volume and simple structure in view of the difficulties encountered in the current design.

The purpose of this utility model is achieved through the following technical solutions:

The microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces includes an upper high dielectric constant dielectric resonator and a lower dielectric substrate; a microstrip feeder is between the upper high dielectric constant dielectric resonator and the lower dielectric substrate; the lower dielectric A copper floor is pasted on the lower surface of the substrate; an input port of the antenna is provided between the microstrip feeder and the copper floor, and is directly connected to the RFID tag chip.

The dielectric constant of the upper high dielectric constant dielectric resonator is preferably 10-100; the size of the upper high dielectric constant dielectric resonator is adjustable, the side length is preferably 10mm-50mm, and the thickness is preferably 2mm-10mm.

The width and length of the microstrip feeder line are adjustable, the width is preferably 1 mm to 3 mm, and the length is preferably 4 mm to 8 mm.

The side length of the copper skin floor can be adjusted within a range of more than one wavelength, and the wavelength is the wavelength corresponding to the frequency of 2.45GHz or 5.8GHz.

Compared with the prior art, the utility model has the following advantages:

(1) The dielectric resonant antenna needs a grounding plate when it works, and the grounding characteristics of the antenna are directly considered in the design, so the antenna is less affected by the ground and can be easily applied to metal surfaces.

(2) There is no conductor loss and surface wave loss in the dielectric resonant antenna, and its radiation efficiency is very high; in addition, because it works on the metal surface, the metal as a reflector not only does not affect the transceiver effect of the antenna, but increases the gain of the antenna. Further improve the label reading distance.

(3) The dielectric resonant antenna adopts a microstrip feeding mode, and the input end of the antenna is a microstrip line, and its impedance is easily matched with the RFID chip in the microwave frequency band, which is convenient for application in the RFID system.

(4) The dielectric resonant antenna has the characteristics of low profile, small volume, simple structure, easy processing and low cost.

Description of drawings

Figure 1 is a schematic diagram of the three-dimensional structure of a dielectric resonant RFID tag antenna in the microwave segment that can work on a metal surface;

Fig. 2 is the front view of Fig. 1;

FIG. 3 is a top view of FIG. 1 .

specific implementation plan

The utility model will be described in further detail below in conjunction with the accompanying drawings, but the scope of protection claimed by the utility model is not limited to the scope of the following examples.

As shown in Figures 1, 2, and 3, the microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces includes an upper high-permittivity dielectric resonator 1 and a lower dielectric substrate 2; an upper high-permittivity dielectric resonator 1 and a lower layer Between the dielectric substrates 2 is a microstrip feeder 4; the lower surface of the lower dielectric substrate 2 is pasted with a copper floor 3; the bottom copper floor 3 mainly plays the role of reflecting electromagnetic energy. When the side length jk is greater than one wavelength, the size The size has little influence on the circuit performance of the antenna; the wavelength mentioned is the wavelength corresponding to the center frequency of the 2.45GHz or 5.8GHz frequency band. The utility model selects the 2.45GHz frequency band, and takes the side length jk as 150mm. In actual application, the attached metal surface can also be used as the underlying copper skin floor 3 .

Between the microstrip feeder 4 and the copper floor 3 is the input port 5 of the antenna, which is directly connected to the RFID tag chip. The input impedance in the working frequency band is adjustable to match the output impedance of the RFID tag chip in actual use. Specifically, the microstrip feeder 4 plays the role of adjusting the impedance matching and resonance frequency of the antenna. When the width fg increases, the input impedance of the antenna decreases, and the resonance frequency moves down; otherwise, the input impedance of the antenna increases, and the resonance frequency increases. shift. When the length gh increases, the input impedance of the antenna decreases and the resonant frequency moves down; otherwise, the input impedance of the antenna increases and the resonant frequency moves up. In order to be conveniently applied to metal surfaces, with high gain, small size and simple structure, the microwave segment ranges from 2400MHz to 2483MHz or 5725MHz to 5875MHz. The adjustable range of fg width is 1mm~3mm, and the adjustable range of length gh is 4mm~8mm .

The resonant frequency of the microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces is determined by the side length ab, thickness bc of the dielectric resonator 1 and the dielectric constant of the dielectric resonator 1 . The larger the side length ab, the thickness bc, and the dielectric constant of the dielectric resonator 1, the smaller the resonant frequency; otherwise, the larger the resonant frequency. In order to meet the purpose of this patent that can be easily applied to the metal surface, has high gain, small size, and simple structure in the microwave section of 2400MHz-2483MHz or 5725MHz-5875MHz, the adjustable range of side length ab is 20mm-40mm, and the thickness bc is adjustable. The range is 3mm-5mm, the dielectric constant of the dielectric resonator 1 can be adjusted in the range of 10-100, and the material can be ceramics. The dielectric substrate 2 mainly plays the role of impedance matching and isolating the dielectric resonator and the copper floor. The side length ed of the dielectric substrate 2 is adjustable. When ed is greater than or equal to the side length ab of the dielectric resonator, its influence on the circuit performance of the antenna is very small; the thickness cd of the dielectric substrate 2 mainly affects the impedance matching of the antenna, the greater the length of cd, the greater the impedance; otherwise, the smaller the impedance of the antenna. In order to meet the purpose of this patent, which can be easily applied to metal surfaces, has high gain, small volume, and simple structure in the microwave section 2400MHz-2483MHz or 5725MHz-5875MHz, the adjustable range of side length ed is 20mm-50mm; the thickness of the dielectric substrate 2 is cd The adjustable range is 0.5mm to 2mm, and FR4 with a dielectric constant of 4.4 can be selected.

The microwave segment RFID tag antenna of the utility model is realized by a dielectric resonance antenna, which directly considers the grounding characteristics of the antenna during design, and the antenna is less affected by the floor, and can be conveniently applied to the metal surface. The radiation efficiency and gain of the antenna are relatively high. Adopting the microstrip feeding method, the impedance matching is easy. It also has the characteristics of low profile, small volume, simple structure, easy processing and low cost.

Claims (4)

1. The microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces is characterized in that it includes an upper high dielectric constant dielectric resonator (1), a lower dielectric substrate (2); an upper high dielectric constant dielectric resonator (1 ) and the lower dielectric substrate (2) is a microstrip feeder (4); the lower surface of the lower dielectric substrate (2) is pasted with a copper floor (3); the microstrip feeder (4) and the copper floor (3 ) is provided with an input port (5) of the antenna, which is directly connected to the RFID tag chip. 2. The microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces according to claim 1, characterized in that the dielectric constant of the upper layer high dielectric constant dielectric resonator (1) is 10-100; the upper layer high dielectric constant The electric constant dielectric resonator (1) is adjustable in size, with a side length of 10 mm to 50 mm and a thickness of 2 mm to 10 mm. 3. The microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces according to claim 1, characterized in that the width and length of the microstrip feeder (4) are adjustable, the width is 1 mm to 3 mm, and the length is 4 mm to 8mm. 4. The microwave segment dielectric resonant RFID tag antenna that can work on metal surfaces according to claim 1, characterized in that the side length of the copper skin floor (3) is adjustable within a range of more than one wavelength, and the wavelength It is the wavelength corresponding to the frequency of 2.45GHz or 5.8GHz.

Images