CN211929703U

CN211929703U - FRID frequency 902-928MHZ four-wall spiral antenna

Info

Publication number: CN211929703U
Application number: CN202020396531.8U
Authority: CN
Inventors: 吴永茂; 何仁志
Original assignee: Yongfutong Technology Shanghai Co ltd
Current assignee: Yongfutong Technology Shanghai Co ltd
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2020-11-13
Anticipated expiration: 2030-03-25

Abstract

The utility model discloses a FRID frequency 902-. The utility model discloses need not to add feed structure in addition, utilize the crust of coaxial cable self and inner core current amplitude equal, the phase difference 180 characteristics, can realize the balanced feed of four arms.

Description

FRID frequency 902-928MHZ four-wall spiral antenna

Technical Field

The utility model relates to an antenna field, in particular to FRID frequency 902-.

Background

The radio frequency identification system is abbreviated as FRID, is a non-contact automatic identification system, automatically identifies a target object through radio frequency wireless signals, acquires related data, and consists of an electronic tag, a reader-writer and a computer network, wherein an antenna is usually used as a converter in the working process of the FRID in the range of frequency 902 plus 928 MHZ.

The antenna is used as a converter to convert a guided wave propagating on a transmission line into an electromagnetic wave propagating in an unbounded medium (usually free space) or vice versa, and a component for transmitting or receiving the electromagnetic wave in a radio device, an engineering system such as radio communication, broadcasting, television, radar, navigation, electronic countermeasure, remote sensing, radio astronomy and the like, all of which transmit information by using the electromagnetic wave, depends on the antenna to operate.

When the existing antenna is used as a converter under the working environment, a feed structure is additionally needed to realize balanced feed of four arms, so that the structural complexity is greatly increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a FRID frequency 902-.

The utility model achieves the purpose through the following technical proposal that the FRID frequency 902-928MHZ four-wall spiral antenna comprises a peripheral guard bar, an upper top cover is rotatably arranged on the outer surface of the upper end of the peripheral guard bar, and the outer surface of the lower end of the peripheral guard bar is rotatably provided with a lower sealing cover, the outer surface of the lower end of the lower sealing cover is provided with an antenna joint, and the outer surface of the peripheral guard bar is provided with a first coaxial cable, a second coaxial cable, a third coaxial cable and a fourth coaxial cable, the inner part of the first coaxial cable is provided with a cable inner core, and one end of the cable inner core is provided with a connecting wire, the cable inner core in the first coaxial cable is connected with the sheath of the third coaxial cable through the connecting wire, the sheath in the first coaxial cable is connected with the sheath of the second coaxial cable, and the sheath of the third coaxial cable is connected with the fourth coaxial cable.

Preferably, the outer surface of the peripheral guard bar is provided with an external thread structure, the upper top cover and the lower sealing cover are of internal thread structures, and the peripheral guard bar can be rotatably installed with the upper top cover and the lower sealing cover.

Preferably, the outer guard bar is a hollow structure, and the outer surface of the outer guard bar is coated with a hydrophobic and oleophobic layer.

Preferably, the number of the first coaxial cable, the second coaxial cable, the third coaxial cable and the fourth coaxial cable is three, and a set of four-wall helical antenna is formed by a set of the first coaxial cable, the second coaxial cable, the third coaxial cable and the fourth coaxial cable.

Preferably, an inclination angle is arranged between the first coaxial cable and the peripheral guard bar, and an inclination angle is arranged between the third coaxial cable and the peripheral guard bar.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses a realize coaxial cable to the balanced feed of antenna arm, make the four arms of antenna all use coaxial cable, be connected the cable inner core of first coaxial cable and third coaxial cable's crust, be connected the crust of first coaxial cable and the crust of second coaxial cable again, connect the crust of third coaxial cable and the crust of fourth coaxial cable at last, because the current amplitude of coaxial cable crust and cable inner core equals, opposite direction, so the electric current on the spiral four arms equals, the utility model discloses need not to add feed structure in addition, can realize the balanced feed of four arms.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a connection diagram of the coaxial cable according to the present invention.

In the figure: 1. the antenna comprises a peripheral guard bar, 2, an upper top cover, 3, a lower sealing cover, 4, an antenna joint, 5, a first coaxial cable, 6, a second coaxial cable, 7, a third coaxial cable, 8, a fourth coaxial cable, 9, a cable inner core, 10 and a connecting wire.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1-2, an FRID frequency 902-, and the outer surface of the lower end of the peripheral guard bar 1 is rotatably provided with a lower sealing cover 3, the outer surface of the lower end of the lower sealing cover 3 is provided with an antenna joint 4, and the outer surface of the peripheral guard bar 1 is provided with a first coaxial cable 5, a second coaxial cable 6, a third coaxial cable 7 and a fourth coaxial cable 8, the inner part of the first coaxial cable 5 is provided with a cable inner core 9, and a connecting wire 10 is installed at one end of the cable inner core 9, the cable inner core 9 in the first coaxial cable 5 is connected with the sheath of the third coaxial cable 7 through the connecting wire 10, the sheath in the first coaxial cable 5 is connected with the sheath of the second coaxial cable 6, and the sheath of the third coaxial cable 7 is connected with the fourth coaxial cable 8.

The outer surface of the peripheral guard bar 1 is provided with an external thread structure, the upper top cover 2 and the lower sealing cover 3 are in internal thread structures, and the peripheral guard bar 1 can be rotatably installed with the upper top cover 2 and the lower sealing cover 3, so that the convenience and the convenience of assembling and disassembling corresponding components are effectively improved;

the peripheral guard bar 1 is of a hollow structure, the outer surface of the peripheral guard bar 1 is coated with a hydrophobic oil-repellent layer, and the hydrophobic oil-repellent layer and the oleophobic layer are arranged, so that the peripheral guard bar has hydrophobic and oleophobic functions, the self weight of the peripheral guard bar 1 is reduced, and the stability of the peripheral guard bar is ensured;

the number of the first coaxial cable 5, the second coaxial cable 6, the third coaxial cable 7 and the fourth coaxial cable 8 is three, and a set of four-wall helical antenna is formed by one set of the first coaxial cable 5, the second coaxial cable 6, the third coaxial cable 7 and the fourth coaxial cable 8, so that the formed four-wall helical antenna has a simple structure, and can realize balanced feed of four arms without adding a feed structure;

the inclination angles are arranged between the first coaxial cable 5 and the peripheral guard bar 1 and between the third coaxial cable 7 and the peripheral guard bar 1, and the arrangement of the inclination angles can effectively prevent the normal communication of the direct antenna caused by mutual influence of the problems of heating and the like in the working state of the three under the feeding state.

The utility model discloses a theory of operation:

the quadrifilar helix antenna is composed of a first coaxial cable 5, a second coaxial cable 6, a third coaxial cable 7 and a fourth coaxial cable 8, can be regarded as being composed of two double-arm helix antennas, and the two double-arm helix antennas rotate by 90 degrees and are fed orthogonally;

for a two-arm helical antenna, when the antenna is in a resonance state, the current amplitude on the arms is close to sinusoidal distribution, wherein the maximum value is located at a feeding point and a short-circuit point, the zero point is located at the middle part of the helical arms, the coaxial cable is used for feeding at the bottom part through the axis, the coaxial cable is used for reversing the current of the inner conductor and the outer conductor, so that the constant-amplitude reverse feeding of the two-arm helical can be realized, the 90-degree phase shift between the two-arm helical can be realized through a self-phase shift structure, namely, the two-arm helical has a certain difference in length, one of the two-arm helical is slightly longer than the length in resonance, an input impedance with-45-degree phase shift relative to the resonance is generated, the other one of the two-arm helical is slightly shorter than the length in resonance, an input impedance with + 45-degree phase shift relative to the resonance is generated, the inner core 9 of the first coaxial cable 5 is connected with the outer skin of the third coaxial cable 7, the outer skin of the first coaxial cable 5 is connected with the outer skin of the second coaxial cable 6, and finally the outer skin of the third coaxial cable 7 is connected with the outer skin of the fourth coaxial cable 8, and the currents on the four spiral arms are equal because the current amplitudes of the coaxial cable outer skin and the inner core 9 are equal and opposite in direction.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An FRID frequency 902-928MHZ four-wall helical antenna, characterized in that: comprises a peripheral guard bar (1), an upper top cover (2) is rotatably arranged on the outer surface of the upper end of the peripheral guard bar (1), a lower sealing cover (3) is rotatably arranged on the outer surface of the lower end of the peripheral guard bar (1), an antenna joint (4) is arranged on the outer surface of the lower end of the lower sealing cover (3), a first coaxial cable (5), a second coaxial cable (6), a third coaxial cable (7) and a fourth coaxial cable (8) are arranged on the outer surface of the peripheral guard bar (1), a cable inner core (9) is arranged inside the first coaxial cable (5), a connecting wire (10) is arranged at one end of the cable inner core (9), the cable inner core (9) in the first coaxial cable (5) is connected with the sheath of the third coaxial cable (7) through the connecting wire (10), the sheath in the first coaxial cable (5) is connected with the sheath of the second coaxial cable (6), the sheath of the third coaxial cable (7) is connected with the fourth coaxial cable (8).

2. The FRID frequency 902-928MHZ four-wall spiral antenna of claim 1, wherein: the outer surface of the peripheral guard bar (1) is provided with an external thread structure, the upper top cover (2) and the lower sealing cover (3) are of internal thread structures, and the peripheral guard bar (1) can be rotatably installed with the upper top cover (2) and the lower sealing cover (3).

3. The FRID frequency 902-928MHZ four-wall spiral antenna of claim 1 or 2, wherein: the peripheral guard bar (1) is of a hollow structure, and the outer surface of the peripheral guard bar (1) is coated with a hydrophobic and oleophobic layer.

4. The FRID frequency 902-928MHZ four-wall spiral antenna of claim 1, wherein: the number of the first coaxial cables (5), the second coaxial cables (6), the third coaxial cables (7) and the fourth coaxial cables (8) is three, and a set of four-wall helical antenna is formed by one set of the first coaxial cables (5), the second coaxial cables (6), the third coaxial cables (7) and the fourth coaxial cables (8).

5. The FRID frequency 902-928MHZ four-wall spiral antenna of claim 1, wherein: and inclined angles are arranged between the first coaxial cable (5) and the peripheral guard bar (1) and between the third coaxial cable (7) and the peripheral guard bar (1).