CN114497995A

CN114497995A - Omnidirectional DTMB antenna

Info

Publication number: CN114497995A
Application number: CN202111570033.6A
Authority: CN
Inventors: 朱广冕; 荆蕾; 高树贤
Original assignee: Yantai Nanshan University
Current assignee: Yantai Nanshan University
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-05-13

Abstract

The invention relates to a wireless signal receiving device, in particular to an omnidirectional DTMB antenna, which comprises a C-shaped conductor bent by a copper pipe or an aluminum pipe, wherein the C-shaped conductor comprises a body section, a long arm section, a short arm section, a long body section connecting the body section with the long arm section and a short body section connecting the body section with the short arm section, the axes of the long arm section and the short arm section are superposed, the axis of the long arm section or the short arm section is parallel to the axis of the body section, the axis of the body section is orthogonal to the axes of the long body section and the short arm section, a body feed point and a short arm feed point are respectively arranged on the body section and the short arm section, the body feed point is connected with an inner terminal of a female seat through a coaxial cable, and the short arm feed point is connected with an outer terminal of the female seat through a coaxial cable. The invention can realize the omnidirectional reception of DTMB signals by a C-shaped conductor which is bent by a copper pipe or an aluminum pipe. Practice tests show that the solar cell panel does not need directional installation, can be placed in an outdoor place where the solar cell panel is not obviously shielded, is free from wind and rain, low in manufacturing cost and long in service life, and has a good receiving effect.

Description

Omnidirectional DTMB antenna

Technical Field

The invention relates to a wireless electromagnetic wave signal receiving device, in particular to an omnidirectional DTMB antenna.

Background

At present, a yagi antenna is used for receiving DTMB signals, and a typical yagi antenna is shown in figure 1 and comprises a main rod 2 fixed on a vertical rod 1, a vibrator is fixed on the main rod 2, and the main rod 2 and the vibrator are integrally shaped like a Chinese character 'wang'. The active oscillator or main oscillator 3 connected with the coaxial cable feeder 6 in the middle, and the reflector 4 longer than the active oscillator on one side of the active oscillator play a role of weakening the electric wave transmitted from the direction or the electric wave transmitted from the antenna; a director 5, which is located on the other side of the active vibrator 3 and is slightly shorter than the active vibrator, enhances the electric wave transmitted from or emitted to this side. The director 5 may be provided in a plurality, each having a length slightly shorter than its adjacent one and close to the active element. The more directors, the sharper the direction and the higher the gain, but actually, the more than four or five directors, the more the "benefit" is increased is less obvious, and the problems of large volume, self weight increase, increased requirements on material strength, increased cost and the like are more prominent, so that four or five directors are usually sufficient.

DTMB, English is called Digital Television Terrestrial Multimedia Broadcasting, and Chinese is called Digital Television Terrestrial Broadcasting. The DTMB is used for realizing global coverage in China, a county and city radio and television bureau transmits DTMB signals and transmits high-frequency electromagnetic waves with specific frequency to all directions, a user installs a DTMB antenna outdoors to receive a part of the high-frequency electromagnetic waves, induced potential and induced current, namely electric signals, are generated on a vibrator and transmitted to a DTMB receiver through a coaxial cable feeder, the electric signals are amplified and the like in the receiver and are finally converted into audio and video signals approved by a television, and the audio and video signals are transmitted to an AV interface of the television through an audio and video line, so that the television can display television programs, and remote mountain areas and field culture farmers can also watch the television.

However, the existing yagi antenna still has certain defects: firstly, because the yagi antenna is a directional antenna, the antenna can deviate from the direction and needs to be readjusted when strong wind occurs; secondly, the vibrator and the conductor should be insulated, but due to long-term weather, plastics can be aged, the insulating property is reduced, and the receiving effect is poor; and the vertical rod for fixing the wire needs to have enough strength, otherwise, the antenna can shake in strong wind to cause unstable signals. The three points all affect the viewing effect, and the service life of the yagi antenna is 2-3 years generally.

Disclosure of Invention

In order to solve one of the defects or shortcomings of the prior art, the invention discloses an omnidirectional DTMB antenna, which adopts the technical scheme that:

an omnidirectional DTMB antenna comprises a C-shaped conductor bent by a copper pipe or an aluminum pipe, wherein the C-shaped conductor comprises a body section, a long arm section, a short arm section, a long body section and a short body section, the long body section is connected with the body section and the long arm section, the short body section is connected with the body section and the short arm section, the axes of the long arm section and the short arm section are overlapped, the axis of the long arm section or the short arm section is parallel to the axis of the body section, the axis of the body section is orthogonal to the axes of the long body section and the short body section, a body feed point and a short arm feed point are respectively arranged on the body section and the short body section, the body feed point is connected with an inner terminal of a coaxial cable connecting female seat through a lead, and the short arm feed point is connected with an outer terminal of the coaxial cable connecting female seat through a lead.

Further, if the distance between the axis of the long arm section and the axis of the short arm section is defined as L2, the distance between the axis of the long body section and the opening end thereof is defined as L1, the distance between the body feed point and the axis of the short body section is defined as L3, and the distance between the short arm feed point and the axis of the short body section is defined as L4, then: l3= L4; l1=1/2 λ mm; l2=3/4 λ mm; l3=1/16 λ -10 mm; λ is the center wavelength of the receiver DTMB signal, which is calculated by equation (r):

λ=0.96×3×10⁵/f ①

wherein f is the center frequency of the receiving ground DTMB signal, which is calculated by equation (II):

f=（f1+f2+f3+…+fn）/n ②

wherein f1-fn is the frequency of each frequency point of the DTMB signal transmitted by the receiving place, and n is the total number of the frequency points of the DTMB signal transmitted by the receiving place.

Further, the distance between the open ends of the long arm section and the short arm section is 10mm, and the distance between the axial line of the long arm section and the axial line of the short arm section and the axial line of the body section is 20 mm.

Furthermore, the outer diameter of the copper pipe or the aluminum pipe is 4-6mm, and the wall thickness is 0.2-0.5 mm.

Further, the C-shaped conductor, the lead wire and the female coaxial cable connection holder other than the screw head are encapsulated in the cured random copolymer polypropylene sheet.

Further, the random copolymer polypropylene plate has more than one lug thereon.

Compared with the prior art, the integrated DTMB signal receiving device has the advantages that the split structure of the active vibrator, the reflector and the director is abandoned, the integrated scheme is that the C-shaped conductor is bent by a copper pipe or an aluminum pipe, the all-round receiving of the DTMB signal can be realized, the practical inspection is realized, the directional installation is not needed, the DTMB signal receiving device can be placed at any place without obvious shielding outdoors, the weather is not feared, the manufacturing cost is low, the good receiving effect is realized, and the service life can reach 50 years after the DTMB signal receiving device is packaged by the random copolymerization polypropylene.

Drawings

Fig. 1 is a schematic structural diagram of a conventional yagi antenna.

Fig. 2 is a schematic structural view of embodiment 1 of the present invention.

Fig. 3 is a schematic front view of a C-shaped conductor according to embodiment 1 of the present invention.

Fig. 4 is a schematic view of an external structure of embodiment 2 of the present invention.

Detailed Description

Example 1 the invention is further illustrated below by way of example in a longut launch station.

The terrestrial broadcasting frequency of the digital television of the longuette transmitting station is shown in the following table:

as can be seen from the above table, the longkou has two frequency points, i.e., f1=498 and f2=514, and the formula = (f 1+ f2+ f3 … + fn)/n represents the center frequency f = (498 + 514)/2 =506MH of the DTMB signal that can be received_Z；

Substituting f into formula (λ =0.96 × 3 × 10)⁵Center wavelength λ =0.96 × 3 × 10 of DTMB signal where/f can be received⁵/506=569.17 mm; wherein 0.96 is the wavelength correction factor.

An omni-directional DTMB antenna as shown in fig. 2-3 comprises a C-shaped conductor 100 as shown in fig. 3 bent by a copper tube having an outer diameter of 6mm and a wall thickness of 0.5mm, for convenience of description, the C-shaped conductor 100 is divided into a body section 101, a long arm section 102, a short arm section 103, a long body section 104 connecting the body section and the long arm section, and a short body section 105 connecting the body section and the short arm section, the axes of the long arm section 102 and the short arm section 103 are coincident, the axis of the long arm section 102 or the short arm section 103 is parallel to the axis of the body section 101, the axis of the body section 101 is orthogonal to the axes of the long body section 104 and the short body section 105, the body feed point 106 and the short arm feed point 107 are respectively arranged on the body section 101 and the short body section 105, two ends of one conducting wire 300 are respectively welded with the body feed point 106 and the inner terminal connected with the coaxial cable connecting female socket 200, and two ends of the other conducting wire 300 are respectively welded with the short arm feed point 107 and the outer terminal connected with the coaxial cable connecting female socket 200.

If the distance from the axis of the long body section 104 to the open end thereof is defined as L1, then L1=1/2 λ mm =569.17/2 ≈ 285 mm;

if the distance between the axis of the long arm segment 102 and the axis of the short arm segment 103 is defined as L2, then L2=3/4 λ mm =569.17 × 3/4 ≈ 427mm;

if the distance between the axis of long body segment 104 and the open end thereof is defined as L1, the distance between body feed point 106 and the axis of short body segment 105 is defined as L3, and the distance between short arm feed point 107 and the axis of short body segment 105 is defined as L4, then L3= L4=569.17/16-10 ≈ 26mm;

the open ends of the long arm segment 102 and the short arm segment 103 are 10mm apart, and the distance between the axis of the long arm segment 102 and the short arm segment 103 and the axis of the shaft segment 101 is 20 mm.

In another preferred embodiment, the copper pipe is replaced by an aluminum pipe, further reducing the cost.

The C-shaped conductor 100, the female coaxial cable connector 200 and the conductor 300 may be fixed by any means, for example, they may be fixed to a plastic plate. Then one end of a 50 omega coaxial cable with a male connector at both ends is inserted into the coaxial cable connecting female seat 200, the other end is inserted into the input port of the DTMB set-top box, the audio and video output end of the set-top box is connected with the audio and video interface of the television through an audio and video cable, the C-shaped conductor 100 receives the DTMB signal in the air and then transmits the DTMB signal to the set-top box, the set-top box demodulates the signal, and the television can receive all 16 sets of television programs, so that the television is very clear. Need not directional installation, can place at will, for example can hang on the peasant household eaves wall, also can fix on a pole top, can directly put even on outdoor windowsill, can both receive the signal well, low in cost, the experiment shows that there is good receiving effect.

Embodiment 2, in order to better fix the C-shaped conductor 100, the female coaxial cable connector 200 and the conductive wire 300, the inventor manufactures a rectangular groove-shaped mold with a rounded corner having a slightly larger outline than the C-shaped conductor 100 with an iron plate, the side wall of the groove-shaped mold is provided with a round hole having an inner diameter slightly larger than the outer diameter of the screw head of the female coaxial cable connector 200, the C-shaped conductor 100 is then placed in the groove-shaped mold in an overhead manner, the screw head of the female coaxial cable connector 200 is exposed outside the side wall of the groove-shaped mold through the round hole, then the random copolymer polypropylene particles are melted and poured into the groove-shaped mold, the C-shaped conductor 100 and the female coaxial cable connector 200 are completely buried, the random copolymer polypropylene is cooled to room temperature, and then the plate-shaped omnidirectional DTMB antenna shown in fig. 4 can be obtained by taking out the random copolymer polypropylene from the groove-shaped mold, the random copolymer polypropylene has high dielectric strength, high weather resistance and no fear of wind and rain, the service life of the packaged plate-shaped omnidirectional DTMB antenna can reach 50 years.

Claims

1. An omni-directional DTMB antenna, comprising: the coaxial cable connection female seat comprises a C-shaped conductor (100) bent by a copper pipe or an aluminum pipe, wherein the C-shaped conductor (100) comprises a body section (101), a long arm section (102), a short arm section (103), a long body section (104) and a short body section (105), the long body section (104) is connected with the body section and the long arm section, the short body section (105) is connected with the body section and the short arm section, the axes of the long arm section (102) and the short arm section (103) are overlapped, the axis of the long arm section (102) or the short arm section (103) is parallel to the axis of the body section (101), the axis of the body section (101) is orthogonal to the axes of the long body section (104) and the short arm section (105), a body feed point (106) and a short arm feed point (107) are respectively arranged on the body section (101) and the short arm section (105), the body feed point (106) is connected with an inner terminal of the coaxial cable connection female seat (200) through a lead (300), and the short arm feed point (107) is connected with an outer terminal of the coaxial cable connection female seat (200) through a lead (300).

2. The omni-directional DTMB antenna of claim 1, wherein: if the distance between the axis of the long arm section (102) and the axis of the short arm section (103) is defined as L2, the distance between the axis of the long body section (104) and the opening end thereof is defined as L1, the distance between the body feed point (106) and the axis of the short body section (105) is defined as L3, and the distance between the short arm feed point (107) and the axis of the short body section (105) is defined as L4, then the following steps are provided: l3= L4; l1=1/2 λ mm; l2=3/4 λ mm; l3=1/16 λ -10 mm; λ is the center wavelength of the receiver DTMB signal, and the center wavelength λ of the receiver DTMB signal is calculated by equation (r):

λ=0.96×3×10⁵/f ①

where f is the center frequency of the received DTMB signal.

3. The center frequency of the received DTMB signal is calculated by equation (ii):

f=（f1+f2+f3+…+fn）/n ②

4. The omni-directional DTMB antenna of claim 1, wherein: the distance between the open ends of the long arm section (102) and the short arm section (103) is 10mm, and the distance between the axes of the long arm section (102) and the short arm section (103) and the axis of the body section (101) is 20 mm.

5. The omni-directional DTMB antenna of claim 1, wherein: the outer diameter of the copper pipe or the aluminum pipe is 4-6mm, and the wall thickness is 0.2-0.5 mm.

6. The omni-directional DTMB antenna of any of claims 1-4, wherein: the C-shaped conductor (100), the lead wire (300) and the female coaxial cable connection socket (200) other than the screw head are encapsulated in a cured random copolymer polypropylene plate (400).

7. The omni-directional DTMB antenna of claim 5, wherein: the random copolymerized polypropylene plate (400) is provided with more than one lug (401).