CN108832294A - Antenna - Google Patents

Abstract

The invention discloses an antenna, which belongs to the technical field of antennas and comprises a radio frequency wire and a screw rod; the radio frequency wire is connected with the spiral rod, and the antenna also comprises a resistance wire for impedance matching; the radio frequency wire and the spiral rod are connected through the resistance wire. The invention mainly solves the problem that the return loss of a commonly used rod sleeve antenna is larger, the antenna carries out impedance matching through the resistance wire, and technicians select a proper resistance value of the resistance wire to carry out impedance matching on the radio frequency wire and the spiral rod during production.

Description

an antenna

technical field

The present invention relates to the technical field of antennas, in particular to an antenna.

Background technique

At present, wireless communication technology is developing at a high speed. Wireless communication is inseparable from electromagnetic waves, and antennas are devices that convert guided waves on transmission lines and electromagnetic waves propagating in space.

Antennas in the prior art usually use impedance matching methods to achieve the purpose of reducing the return loss of the antenna. For example, a common pole sleeve antenna encapsulates interconnected radio frequency lines and helical rods in the pole sleeve; the radio frequency line connects the signal The source and the screw rod, the electrical signal of the signal source is transmitted to the screw rod through the radio frequency line, and the screw rod radiates the signal to the space in the form of electromagnetic waves. In the prior art, impedance matching is usually achieved by adjusting the size parameters of the screw rod .

The above-mentioned impedance matching method, because it is difficult to adjust the size of the screw rod to adjust the satisfactory impedance value, so the effect of reducing the return loss is not very good, the return loss is relatively large, and the return loss of the commonly used rod sleeve antenna is -6dB about.

Contents of the invention

In order to solve the above problems, the present invention provides an antenna, which implements impedance matching by connecting resistors in series, so as to reduce the return loss of the antenna.

The technical solution adopted by the present invention is: an antenna, including a radio frequency wire and a helical rod; The rods are connected through the resistance wire; during production, technicians select the appropriate resistance value of the resistance wire to perform impedance matching on the radio frequency wire and the screw rod. Since the resistance value of the resistance wire is easier to control, compared with adjusting the size of the screw rod, Choosing the resistance value of the resistive wire makes it easier to impedance match the RF wire and the helical rod, thereby reducing the return loss of the antenna.

In the above technical solution, the radio frequency line includes an outer conductor and an inner conductor that are insulated from each other; the outer conductor is wrapped outside the inner conductor to receive and shield external interference signals.

In the above technical solution, the outer conductor is coaxial with the inner conductor.

In the above technical solution, the antenna further includes a grounded copper pipe, and the outer conductor is connected to the grounded copper pipe to form a loop, so that the outer conductor can receive and shield clutter signals.

In the above technical solution, the antenna further includes a radiating copper tube, and the inner conductor of the radio frequency line is connected to the radiating copper tube to enhance the radiation effect of the signal.

In the above technical solution, the resistance wire passes through the radiation copper tube.

In the above technical solution, the antenna further includes a standard interface connected to the radio frequency line, and the standard interface enables the antenna to be quickly connected to a signal source.

In the above technical solution, this kind of antenna also includes a heat-shrinkable sleeve, and the heat-shrinkable sleeve wraps the connection point between the helical rod and the resistance wire to reinforce the connection point between the helix rod and the resistance wire .

In the above technical solution, the impedance matching of the screw rod and the radio frequency line is performed by the following formula:

Z _l × Z ₀ = Z _r

Wherein, Z ₁ is the impedance of described screw rod;

Z ₀ is the characteristic impedance of the radio frequency line;

Z _r is the impedance of the resistance line.

The beneficial effects of the present invention are:

1. This type of antenna performs impedance matching through resistance wires. During production, technicians select the appropriate resistance value of resistance wires to match the impedance of the radio frequency wire and the screw rod. Since the resistance value of the resistance wire is easier to control, compared with adjusting the spiral The size of the rod, the selection of the resistance value of the resistance wire can more easily match the impedance of the RF wire and the helical rod, thereby reducing the return loss of this antenna more effectively;

2. This kind of antenna includes a radiating copper tube, and the inner conductor of the radio frequency line is connected with the radiating copper tube, which strengthens the radiation effect of the signal, and enables the signal to radiate in all directions, so that the signal can be distributed in a wider range of space;

3. This kind of antenna includes a helical rod, which can shorten the length of the antenna compared with a linear vibrator.

Description of drawings

Fig. 1 is a structural diagram of an antenna of the present invention;

Fig. 2 is a return loss curve diagram of an antenna in the prior art measured by a network analyzer;

Fig. 3 is to use network analyzer to measure the return loss curve figure of a kind of antenna provided by the present invention;

Reference signs are: 1. radio frequency line; 2. grounding copper pipe; 3. radiation copper pipe; 4. resistance wire; 5. heat shrinkable sleeve; 6. screw rod; 7. rod sleeve; , Standard interface.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in FIG. 1 , an antenna includes a radio frequency line 1 , a ground copper pipe 2 , a radiation copper pipe 3 , a resistance wire 4 , a spiral rod 6 , a rod sleeve 7 and a standard interface 9 .

The rod sleeve 7 is made of plastic material, and its interior is hollow to form an accommodating cavity 71 .

Viewed from the direction of FIG. 1 , this kind of antenna is placed horizontally. From the right end to the left end of the accommodating cavity 71 of the rod cover 7 there are: radio frequency wire 1 , resistance wire 4 and screw rod 6 .

The radio frequency line 1 includes an outer conductor and an inner conductor; the outer conductor is wrapped outside the inner conductor and is insulated from the inner conductor. Specifically, the inner conductor is covered with an inner insulating layer, and the braided outer conductor is wrapped inside Outside the insulating layer, the outer conductor is also covered with an outer insulating layer; that is, the radio frequency line 1 is the inner conductor, the inner insulating layer, the outer conductor and the outer insulating layer from the inside to the outside; and the outer conductor and the inner conductor are coaxial .

The radio frequency line 1 passes through the ground copper pipe 2, and there is a gap between the radio frequency line 1 and the ground copper pipe 2. The outer conductor of the radio frequency line 1 is connected to the ground copper pipe 2. Specifically, the outer conductor of the radio frequency line 1 The left end and the left end of the grounding copper pipe 2 are fixed together, and the signal can flow into the grounding copper pipe 2 from the outer conductor. The outer conductor of the radio frequency line 1 is connected to the ground copper pipe 2 to form a loop, so that the outer conductor can receive and shield clutter signals, and prevent clutter from affecting the guided wave in the inner conductor.

The right end of the inner conductor of the radio frequency line 1 is connected to the signal source of the antenna through a standard interface 9, the standard interface 9 is an SMA connector or an IPEX connector, and the shell of the standard interface 9 is rotatably connected to the pole sleeve 7 through a connecting shaft 8. The inner conductor of the radio frequency line 1 can also be connected to the signal source of the antenna by welding.

The left end of the inner conductor of the radio frequency line 1 is respectively connected with the resistance wire 4 and the radiation copper pipe 3. Specifically, the radiation copper pipe 3 is a hollow copper pipe, the resistance wire 4 passes through the radiation copper pipe 3, and the resistance wire 4 is two The ends pass through the two ends of the radiation copper pipe 3 respectively, and the left end of the inner conductor of the radio frequency line 1 is connected with the right end of the resistance wire 4 and the right end of the radiation copper pipe 3 respectively.

The left end of the resistance wire 4 is connected with the helical rod 6, which is the vibrator of the antenna, and the helical rod 6 is a helical metal.

The antenna also includes a heat-shrinkable sleeve 5 , the left end of the heat-shrinkable sleeve 5 covers the contact point between the resistance wire 4 and the screw rod 6 , and the right end of the heat-shrinkable sleeve 5 covers the left end of the radiation copper tube 3 .

The signal starts from the signal source and is transmitted through the radio frequency line 1. Part of the signal is radiated into the space by the radiation copper tube 3, and part of it continues to pass through the resistance line 4, and then enters the screw rod 6 and is radiated into space by the screw rod 6.

The principle of impedance matching of this kind of antenna is: select the appropriate resistance value of the resistance wire 4 to carry out impedance matching to the radio frequency line 1 and the screw rod 6, because the resistance value of the resistance wire 4 is easier to control, compared with adjusting the size of the screw rod 6 , selecting the resistance value of the resistance wire 4 can more easily perform impedance matching on the radio frequency wire 1 and the helical rod 6, thereby reducing the return loss of the antenna more effectively.

In one embodiment, the antenna operates in the frequency range of 470MHz-510MHz, the characteristic impedance of the radio frequency line 1 is 50Ω, the inner diameter of the grounding copper pipe 2 is 7.5mm, and the inner diameter of the radiating copper pipe 3 is 5.2mm.

Select the appropriate impedance of the resistance line 4 to match the load impedance with the characteristic impedance of the radio frequency line 1, so as to reduce the return loss of this antenna.

The specific method is:

1. Measure the characteristic impedance Z ₀ of the radio frequency line 1;

2. Measure the impedance value Z _l of the screw rod 6;

3. The characteristic impedance Z ₀ of the radio frequency line 1 is multiplied by the impedance value Z _l of the screw rod 6, and the obtained value Z _r is used as the impedance value of the resistance line 4.

In the above method, the formula for impedance matching is:

Z _l × Z ₀ = Z _r

Wherein, Z ₁ is the impedance of screw rod 6;

Z ₀ is the characteristic impedance of the radio frequency line 1;

Z _r is the impedance of the resistance line 4 .

When using a network analyzer to test the return loss of this type of antenna, the antenna to be tested is fixed on the test bench, and the standard interface 9 of the antenna is connected to the network analyzer through a test cable, and the return loss value is directly displayed by the network analyzer Read out from the screen and export the images in Figures 2 and 3 from the network analyzer.

As shown in Figure 2, the return loss of the prior art antenna operating in the 470MHz-510MHz frequency band is above -9dB in the 470MHz-510MHz frequency band, and the return loss measured at the 470MHz frequency is -6.7217dB, the return loss measured at 490MHz is -7.6165dB, and the return loss measured at 510MHz is -8.5113dB.

As shown in Figure 3, the return loss of the antenna provided in this embodiment is below -9dB in the frequency band of 470MHz-510MHz, and the return loss value measured at the frequency of 470MHz is -15.109dB. The return loss measured at 490MHz is -12.884dB, and the return loss measured at 510MHz is -10.659dB.

In the frequency band of 470MHz-510MHz, compared with the antenna in the prior art, the return loss of the antenna provided by this embodiment is lower.

The above embodiments are only intended to illustrate rather than limit the present invention, so all equivalent changes or modifications made according to the methods described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims (9)

1. a kind of antenna, including radio frequency line (1) and screw rod (6)；The radio frequency line (1) and screw rod (6) connection, feature exist In further including the resistive conductor (4) for impedance matching；The radio frequency line (1) and the screw rod (6) pass through the resistive conductor (4) it connects.

2. a kind of antenna according to claim 1, it is characterised in that：The radio frequency line (1) includes that the outer of mutually insulated is led Body and inner conductor；The outer conductor is coated on outside the inner conductor.

3. a kind of antenna according to claim 2, it is characterised in that：The outer conductor and the inner conductor are coaxial.

4. a kind of antenna according to claim 2 or 3, it is characterised in that：It further include copper earth tube (2), the outer conductor It is connect with the copper earth tube (2).

5. a kind of antenna according to claim 2 or 3, it is characterised in that：It further include radiation copper pipe (3), the radio frequency line (1) inner conductor is connect with the radiation copper pipe (3).

6. a kind of antenna according to claim 5, it is characterised in that：The resistive conductor (4) is out of described radiation copper pipe (3) It passes through.

7. a kind of antenna according to claim 1,2 or 3, it is characterised in that：It further include standard interface (9), the standard Interface (9) is connect with the radio frequency line (1).

8. a kind of antenna according to claim 1,2 or 3, it is characterised in that：It further include heat-shrinkable T bush (5), the pyrocondensation The tie point of casing (5) the cladding screw rod (6) and the resistive conductor (4).

9. a kind of antenna according to claim 1, it is characterised in that：The screw rod (6) and the radio frequency line (1) pass through Following formula carries out impedance matching：

Z_l×Z₀=Z_r

Wherein, Z_lFor the impedance of the screw rod (6)；

Z₀For the characteristic impedance of the radio frequency line (1)；

Z_rFor the impedance of the resistive conductor (4).