CN203134983U - A coupled feeding horizontal omnidirectional annular RFID label antenna - Google Patents

Abstract

The utility model relates to a coupled feeding horizontal omnidirectional annular RFID label antenna. Most of conventional RFID antennas have dipole structures and have radiation patterns vertical to the surfaces of the antennas. Generally, the conventional RFID antenna is used on the vertical surface of an object. When the vertical outer surface of a target object cannot provide available area for the RFID label, the structure is no longer suitable. The coupled feeding horizontal omnidirectional annular RFID label antenna comprises a substrate, a radiation outer loop antenna, and a coupled feeding inner loop structure. The radiation outer loop antenna and the coupled feeding inner loop structure are disposed on the substrate and are arranged concentrically. The coupled feeding horizontal omnidirectional annular RFID label antenna with little structure may operate in FCC frequency range (902 to 928 MHz) and can be attached to the top and the bottom surface of the target object. The radiation pattern is omnidirectional on a horizontal plane and reading distance may reach 9.5 m farthest.

Description

A kind of coupling feed horizontal omnidirectional annular RFID label antenna

Technical field

The utility model belongs to antenna technology and wireless communication field, relates to a kind of coupling feed horizontal omnidirectional annular RFID label antenna.

Background technology

Radio-frequency (RF) identification is RFID(Radio Frequency Identification) technology, claim electronic tag, radio frequency identification again, be a kind ofly can identify specific objective and read and write related data by radio signals, and need not to set up between recognition system and the specific objective communication technology that machinery or optics contact.Passive RFID commonly used has low frequency (125k～134.2K), high frequency (13.56Mhz), hyperfrequency (860-960MHz).

The RFID label antenna is as the important component part of rfid system, and its performance will influence efficient and the quality of whole rfid system greatly.The principal element that influences the RFID antenna performance comprises the size of antenna, working frequency range, impedance and gain etc.General RFID antenna commonly used often adopts bending line style dipole form, is convenient to reduce the processing of antenna size and antenna.The type antenna pattern is perpendicular to antenna surface, is attached at the target object tapered outer surface when therefore using.

When the vertical side of target object provided the space that the RFID label attaches for irregular or insufficient area, the RFID labeling requirement was attached at end face or the bottom surface of target object, and the RFID antenna of dipole form is no longer suitable.In order to tackle this special circumstances, the RFID label antenna that directional diagram is parallel to antenna surface is a kind of reasonable selection.

Summary of the invention

The utility model provides a kind of coupling feed horizontal omnidirectional annular RFID label antenna at the deficiencies in the prior art.

The utility model comprises ring structure in substrate, radiation outer shroud and the coupling feed, and ring is concentric structure in radiation outer shroud and the feed.

Periodically load four interdigital capacitors in the described radiation outer shroud, four interdigital capacitor structures are identical.

Ring loads an interdigital capacitor and a RFID chip in the described feed, and electric capacity and chip are about ring center of circle symmetry in the feed.

Described coupling feed horizontal omnidirectional annular RFID label antenna is operated in the FCC frequency range, i.e. the 902-928MHz frequency range.

The technical solution adopted in the utility model is:

Coupling feed horizontal omnidirectional annular RFID label comprises ring structure in substrate, radiation outer shroud and the coupling feed, and ring is concentric structure in radiation outer shroud and the feed.

Wherein, periodically load four interdigital capacitors in the radiation outer shroud, four interdigital capacitor structures are identical;

Wherein, ring loads an interdigital capacitor and a RFID chip in the feed, and electric capacity and chip are about ring center of circle symmetry in the feed.

The beneficial effect that the utlity model has is:

RFID antenna of the present utility model has small-scale structure, and can be operated under the FCC frequency range (902-928MHz), antenna has good omni-directional at horizontal plane simultaneously, and its reading distance can reach 9.5m, and use end face and the bottom surface that can be attached at target object.This antenna has good adjustable characteristic simultaneously, can easily realize the adjusting of overall dimensions by the electric capacity of regulating outer shroud and interior ring.

Description of drawings

Fig. 1 is the overall structure figure of antenna;

Fig. 2 is the structure chart of interdigital capacitor in the outer shroud;

Fig. 3 is the structure chart of the interdigital capacitor in the interior ring;

Fig. 4 is the input impedance test result figure of antenna.

Fig. 5 is the reading distance resolution chart of label.

The directivity resolution chart of label when Fig. 6 is 925MHz.

Embodiment

Below in conjunction with accompanying drawing the utility model is further described:

As shown in Figure 1, the MIMO antenna is made up of ring 1-2 in radiation outer shroud 1-1 and the feed in the utility model.The overall dimension of antenna is 43mm * 43mm, and what substrate 1-6 adopted is PET material commonly used in the processing of RFID label, and its dielectric constant is 4.3, and structural parameters are 45mm * 45mm * 0.05mm.The cycle loads four interdigital capacitor 1-3 that structure is identical on the outer shroud, and interior ring loads an interdigital capacitor 1-4, and ring is gone up and the interdigital capacitor symmetry in RFID chip 1-5 places.Outer shroud radius (middle to ring width from the center of circle) is 20mm, ring width 3mm; Interior ring radius (middle to ring width from the center of circle) is 10mm, ring width 3mm.

The structure of the interdigital capacitor that outer shroud loads as shown in Figure 2, it is by 3 pairs of interdigital compositions.Every pair interdigital be two parallel and in the metal structure at regular intervals of parallel direction.Refer to that length is 13.1 mm, finger beam is 0.3mm, refers to that spacing is 0.24mm, and the parallel direction spacing between a pair of finger (such as 2-1 and 2-2) is 0.3mm.

In the interdigital capacitor structure that loads of ring as shown in Figure 3, it is to refer to become arc by the level among Fig. 2 refer to.Its middle finger length is 78 ° (with respect to interior rings), and finger beam is 0.3mm, refers to that spacing is 0.24mm, and the displacement between a pair of finger is 2 °.

The input impedance of this antenna measurement as shown in Figure 4, measured impedance is 11+144j ohm when 925MHz, reaches conjugate impedance match with the impedance 11+143j of chip Monza4Dura.Label can reach optimal effectiveness when 925MHz.

The test of label farthest reading distance as shown in Figure 5, when 925MHz, reading distance can reach 9.5m farthest, and is good in FCC frequency range (902-928MHz) interior label performance.

The reading distance of label different directions when 925MHz as shown in Figure 6, different angles position measurement on antenna surface, the reading distance of antenna is 9.32-9.5m, omni-directional is good on antenna surface.

The advantage of RFID label of the present utility model comprises:

(1) size is little and reading distance is far away.As Fig. 1, the size of entire antenna has only 43mm * 43mm, is type comparatively small-sized in the RFID antenna.The reading distance farthest of label can reach 9.5m, far surpasses other RFID labels of similar size.

(2) work of FCC frequency range is good.As shown in Figure 5, antenna can operate as normal under the FCC frequency range, be 4.2-9.5m at its reading distance of this channel, satisfy the design needs of most of RFID application scenario.

(3) omni-directional is good.As Fig. 6, RFID label reading distance deviation on antenna surface is no more than 0.2mm, has good omni-directional.

(4) adjustability is strong.When antenna size changes, just can reorientate frequency easily and realize impedance matching as long as the interdigital capacitor that change outer shroud and interior ring load refers to length.This antenna can be designed as any size in theory.

The utility model has been stated a kind of coupling feed horizontal omnidirectional annular RFID label antenna, use donut to be radiation loop antenna feed innovatively, while loading capacitance on radiation ring and electric feedback ring, make the RFID antenna be easy to regulate operating frequency and input impedance, entire antenna is small-sized simultaneously, and omni-directional is good on antenna surface, is applicable to the end face or the bottom surface that are attached to target object.What antenna substrate adopted in the utility model is the PET material, is one of base material the most frequently used in the RFID processing.And other structures all are to be made with the aluminium etching and processing, and are with low cost and easy to process.In sum, the RFID label antenna of designing has not only overcome the problem that only is applicable to the target object vertical side of traditional RFID antenna, but also it is little to have size, reading distance is far away, and omni-directional is good, and is simple in structure, therefore low cost and other advantages has wide application value and market potential.

Claims (1)

1. a coupling feed horizontal omnidirectional annular RFID label antenna comprises ring structure in substrate, radiation outer shroud and the coupling feed, and it is characterized in that: ring is concentric structure in radiation outer shroud and the feed;

Periodically load four interdigital capacitors in the described radiation outer shroud, four interdigital capacitor structures are identical;

Ring loads an interdigital capacitor and a RFID chip in the described feed, and electric capacity and chip are about ring center of circle symmetry in the feed;

Described coupling feed horizontal omnidirectional annular RFID label antenna is operated in the FCC frequency range, i.e. the 902-928MHz frequency range.

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