Broadband center-fed antenna matching coil

Abstract

The utility model relates to the technical field of antennas, in particular to a broadband center-fed antenna matching coil, which comprises a magnetic core, a first cable and a second cable. The first cable and the second cable are both wound on the magnetic core, an inner core of the first cable and an inner core of the second cable are connected in series, and the winding turn number ratio of the first cable to the second cable is 3: 6 to 4: 6; the impedance of the first cable ranges from 45 ohms to 55 ohms, the impedance of the second cable ranges from 70 ohms to 80 ohms, the length of the first cable ranges from 360 mm to 400 mm, and the length of the second cable ranges from 485 mm to 525 mm. The broadband center-fed antenna matching coil provided by the utility model is used for overcoming the defects of limited frequency band and high standing-wave ratio of the existing matching coil.

Description

Technical Field

[0001] The utility model relates to the technical field of antennas, in particular to a matching coil for a wide-band mid-feed antenna. Background Art

[0002] A center-fed antenna is a ground-independent antenna that is fed from the middle of the antenna. The prior art discloses an ultra-short wave VHF vehicle-mounted broadband center-fed antenna, which includes a SFF-50-1.5-1 coaxial RF cable about 900 mm long, which is evenly wound around three stacked R40C1 magnetic rings. It forms a two-port matching coil with an operating frequency band of 33 to 88 MHz and a voltage standing wave ratio of less than or equal to 4 in the entire frequency band. Its disadvantage is that the bandwidth with a standing wave ratio less than 3 is only 12 MHz, and the standing wave ratio is as high as 3.0 at 88 MHz.

[0003] It can be seen that in the entire 33-88MHz operating frequency band, the bandwidth of the existing matching coil with a standing wave ratio less than 3 is only 12MHz, which cannot meet the communication requirements at certain specific frequencies. Moreover, at 88MHz, the standing wave ratio is as high as 3, which increases signal reflection and loss, affecting the communication quality and efficiency. In addition, the winding formula of the existing matching coil is uniformly distributed, and the spacing of each turn of the coil must be kept equal for a long time. The production process is complex and the reliability is not high. Utility Model Content

[0004] The utility model provides a broadband center-fed antenna matching coil, which is used to solve the defects of the existing matching coils, such as limited frequency band and high standing wave ratio.

[0005] The utility model provides a broadband center-fed antenna matching coil, comprising a magnetic core, a first cable and a second cable;

[0006] The first cable and the second cable are both wound around the magnetic core, the inner core of the first cable is connected in series with the inner core of the second cable, and the ratio of the number of windings of the first cable and the second cable is 3:6 to 4:6;

[0007] The impedance of the first cable is 45 ohms to 55 ohms, the impedance of the second cable is 70 ohms to 80 ohms, the length of the first cable is 360 mm to 400 mm, and the length of the second cable is 485 mm to 525 mm.

[0008] According to the broadband center-fed antenna matching coil provided by the utility model, the first cable and the second cable are tightly wound around the magnetic core so that the gap between adjacent turns of the cable is zero.

[0009] According to the broadband center-fed antenna matching coil provided by the utility model, the magnetic core includes three adjacent magnetic rings, and the gap between the adjacent magnetic rings is zero.

[0010] According to the broadband center-fed antenna matching coil provided by the utility model, the ratio of the number of windings of the first cable and the second cable is 3:5.

[0011] According to the broadband center-fed antenna matching coil provided by the utility model, the impedance of the first cable is 50 ohms, and the impedance of the second cable is 75 ohms.

[0012] According to the broadband center-fed antenna matching coil provided by the utility model, the length of the first cable is 380 mm, and the length of the second cable is 505 mm.

[0013] The broadband center-fed antenna matching coil provided by the utility model further includes a first heat shrinkable sleeve, which is sleeved at the connection between the inner core of the first cable and the inner core of the second cable.

[0014] The broadband mid-feed antenna matching coil provided by the utility model further includes a second heat shrinkable sleeve, one end of which is sleeved on the dielectric layer of the first cable, and the second end of which is sleeved on the dielectric layer of the second cable.

[0015] The broadband mid-feed antenna matching coil provided by the utility model further includes a coaxial cable shielding layer, one end of the coaxial cable shielding layer is connected to the shielding layer of the first cable, and the other end of the coaxial cable shielding layer is connected to the shielding layer of the second cable.

[0016] The broadband center-fed antenna matching coil provided by the utility model further includes a third heat shrinkable sleeve, and the third heat shrinkable sleeve is sleeved on the coaxial cable shielding layer.

[0017] The wide-band center-fed antenna matching coil provided by the utility model can improve the impedance matching effect of the coil, reduce the standing wave ratio at a specific frequency, improve the communication quality and anti-interference capability, and make the call distance longer by connecting in series the inner cores of a first cable with an impedance range of 45 ohms to 55 ohms and a length of 360mm to 400mm and a second cable with an impedance range of 70 ohms to 80 ohms and a length of 485mm to 525mm, and winding them on the magnetic core according to a winding turn ratio of 3:6 to 4:6.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic diagram of a broadband center-fed antenna matching coil provided by an embodiment of the utility model;

[0021] Figure 2 It is a schematic diagram of the connection between the first cable and the second cable in the matching coil of the wide-band center-fed antenna provided by an embodiment of the utility model;

[0022] Figure 3 This is a voltage standing wave ratio test diagram of a wide-band center-fed antenna matching coil provided by an embodiment of the utility model.

[0023] Reference numerals:

[0024] 1. Magnetic core; 2. First cable; 3. Second cable; 4. First heat shrink tubing; 5. Second heat shrink tubing; 6. Coaxial cable shielding layer; 7. Third heat shrink tubing; 8. Fixing tape. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In the description of the embodiments of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific circumstances.

[0028] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0030] Combine the following Figures 1 to 3 The utility model describes a broadband center-fed antenna matching coil.

[0031] See also Figure 1 and Figure 2 As shown, the broadband center-fed antenna matching coil provided by the embodiment of the utility model includes a magnetic core 1 , a first cable 2 and a second cable 3 .

[0032] The first cable 2 and the second cable 3 are both wound around the magnetic core 1, the inner core of the first cable 2 is connected in series with the inner core of the second cable 3, and the winding turn ratio of the first cable 2 to the second cable 3 is 3:6 to 4:6;

[0033] The impedance of the first cable 2 is 45 ohms to 55 ohms, the impedance of the second cable 3 is 70 ohms to 80 ohms, the length of the first cable 2 is 360 mm to 400 mm, and the length of the second cable 3 is 485 mm to 525 mm. It should be noted that the length of the first cable 2 and the length of the second cable 3 specifically refer to the total length of the first cable 2 and the second cable 3.

[0034] The wide-band center-fed antenna matching coil provided by the utility model can improve the impedance matching effect of the coil, reduce the standing wave ratio at a specific frequency, improve the communication quality and anti-interference ability, and make the call distance longer by connecting in series the inner cores of a first cable 2 with an impedance range of 45 ohms to 55 ohms and a length of 360mm to 400mm and a second cable 3 with an impedance range of 70 ohms to 80 ohms and a length of 485mm to 525mm, and winding them on a magnetic core 1 according to a winding turn ratio of 3:6 to 4:6.

[0035] Experimental results show that the wide-band center-fed antenna matching coil provided by the utility model has a standing wave ratio of less than 4 in the entire frequency band from 30MHz to 88MHz, and the bandwidth with a standing wave ratio of less than 3 is 43MHz, especially less than 2 at 88MHz.

[0036] It should be noted that, in this embodiment, the first cable 2 and the second cable 3 wound on the magnetic core 1 are insulated from each other, so that the turns of the coil will not be broken down and form a short circuit when the voltage passes through instantly. The magnetic core 1 and the coil in the coil of the choke (the choke refers to an inductive coil that resists alternating current) are insulated from each other, so that the magnetic core 1 and the coil will not be broken down when the voltage passes through instantly. The coil wound with the first cable 2 and the second cable 3 is a single layer, which is used to reduce the parasitic capacitance of the choke coil, enhance the coil's ability to withstand the instantaneous voltage, and prevent voltage breakdown.

[0037] Specifically, in a preferred embodiment of the present invention, the first cable 2 is a SFF-50-1.5-1 type 50 ohm coaxial cable, the second cable 3 is a SFF-75-1.5-1 type 75 ohm coaxial cable, the winding turn ratio of the first cable 2 and the second cable 3 is 3:5, the length of the first cable 2 is 380 mm, and the length of the second cable 3 is 505 mm. Figure 3 As shown, by controlling the specifications of the matching coil within the above parameters, the impedance matching effect of the coil can be further improved and the standing wave ratio at a specific frequency can be reduced.

[0038] See also Figure 1As shown, according to some embodiments of the utility model, the first cable 2 and the second cable 3 are tightly wound around the magnetic core 1 so that the gap between adjacent turns of the cable is zero. By tightly winding the first cable 2 and the second cable 3 around the magnetic core 1, the difficulty of winding the cable can be reduced compared to the uniform winding method (the gap between adjacent coils is equal and greater than zero), making the matching coil more suitable for mass production. In addition, by tightly winding the first cable 2 and the second cable 3 around the magnetic core 1, the standing wave ratio of the matching coil at a specific frequency can be further reduced.

[0039] See also Figure 1 As shown, according to some embodiments of the utility model, the magnetic core 1 includes three adjacent magnetic rings, and the gap between the adjacent magnetic rings is zero. By setting the magnetic core 1 as three adjacent magnetic rings, the magnetic coupling effect can be enhanced, which helps to improve the impedance matching effect of the matching coil, thereby reducing the reflection and loss of the signal and improving the overall performance and efficiency of the antenna system. In addition, it can also make the entire magnetic ring system have higher magnetic permeability and magnetic properties, and can better control the frequency response characteristics of the coil.

[0040] Specifically, in this embodiment, the magnetic ring is an R40C1 type magnetic ring, and adjacent magnetic rings can be connected by bonding.

[0041] According to some embodiments of the present invention, the magnetic core 1 is a nickel-molybdenum alloy powder magnetic core 1. The nickel-molybdenum alloy powder magnetic core 1 has the characteristics of high magnetic permeability and low loss, is suitable for applications in a wide frequency range, and has high saturation magnetic induction intensity and good stability.

[0042] See also Figure 2 As shown, according to some embodiments of the utility model, the broadband mid-feed antenna matching coil further includes a first heat shrinkable sleeve 4, which is sleeved at the connection between the inner core of the first cable 2 and the inner core of the second cable 2. By providing the first heat shrinkable sleeve 4, the inner cores of the first cable 2 and the second cable 3 can be connected and fixed, and additional insulation protection is provided to prevent the inner cores of the first cable 2 and the second cable 3 from being damaged or contaminated by the external environment, thereby protecting the stability and reliability of the line.

[0043] See also Figure 2 As shown, according to some embodiments of the utility model, the broadband center-fed antenna matching coil further includes a second heat shrinkable sleeve 5, one end of the second heat shrinkable sleeve 5 is sleeved on the dielectric layer of the first cable 2, and the second end of the second heat shrinkable sleeve 5 is sleeved on the dielectric layer of the second cable 3. By providing the second heat shrinkable sleeve 5, the dielectric layers of the first cable 2 and the second cable 3 can be connected and fixed, and additional insulation protection is provided to prevent the dielectric layer of the cable from being damaged or contaminated by the external environment, thereby protecting the stability and reliability of the line.

[0044] See also Figure 2 As shown, according to some embodiments of the utility model, the wideband mid-feed antenna matching coil further includes a coaxial cable shielding layer 6, one end of the coaxial cable shielding layer 6 is connected to the shielding layer of the first cable 2, and the other end of the coaxial cable shielding layer 6 is connected to the shielding layer of the second cable 3. By providing the coaxial cable shielding layer 6, the shielding layers of the first cable 2 and the second cable 3 can be connected to each other to suppress the influence of external interference signals and improve the stability and reliability of signal transmission.

[0045] Specifically, in this embodiment, two ends of the coaxial cable shielding layer 6 are respectively connected to the shielding layers of the first cable 2 and the second cable 3 by welding.

[0046] See also Figure 2 As shown, according to some embodiments of the utility model, the broadband mid-feed antenna matching coil further includes a third heat shrinkable sleeve 7, and the third heat shrinkable sleeve 7 is sleeved on the coaxial cable shielding layer 6. By providing the third heat shrinkable sleeve 7, a certain mechanical protection effect can be provided to the coaxial cable shielding layer 6, and the coaxial cable shielding layer 6 can be insulated from the outside.

[0047] See below Figure 1 and Figure 2 , a specific example is given to illustrate the wide-band mid-feed antenna matching coil provided by the utility model.

[0048] The broadband center-fed antenna matching coil provided by the utility model comprises a magnetic core 1, a first cable 2, a second cable 3, a first heat shrinkable sleeve 4, a second heat shrinkable sleeve 5, a coaxial cable shielding layer 6, a third heat shrinkable sleeve 7 and a fixing belt 8.

[0049] Among them, the magnetic core 1 is a nickel-molybdenum alloy powder magnetic core 1, which includes three adjacent magnetic rings, and the gap between adjacent magnetic rings is zero. The first cable 2 is a SFF-50-1.5-1 type 50 ohm coaxial cable, and its length is 380mm, and the second cable 3 is a SFF-75-1.5-1 type 75 ohm coaxial cable, and its length is 505mm. The inner cores of the first cable 2 and the second cable 3 are connected in series and tightly wound on the magnetic core 1, so that the gap between adjacent coils is zero, and the winding turn ratio of the first cable 2 and the second cable 3 is 3:5. By setting the above specifications of the magnetic core 1, the first cable 2 and the second cable 3, and the winding method of the first cable 2 and the second cable 3, the impedance matching effect of the coil can be improved, and the standing wave ratio at a specific frequency can be reduced, the communication quality and anti-interference ability can be improved, and the call distance can be longer.

[0050] The first heat shrinkable sleeve 4 is sleeved at the connection between the inner core of the first cable 2 and the inner core of the second cable 2; one end of the second heat shrinkable sleeve 5 is sleeved on the dielectric layer of the first cable 2, and the second end of the second heat shrinkable sleeve 5 is sleeved on the dielectric layer of the second cable 3; one end of the coaxial cable shielding layer 6 is welded and connected to the shielding layer of the first cable 2, and the other end of the coaxial cable shielding layer 6 is welded and connected to the shielding layer of the second cable 3; the third heat shrinkable sleeve 7 is sleeved on the coaxial cable shielding layer 6. By setting the first heat shrinkable sleeve 4, the inner cores of the first cable 2 and the second cable 3 can be connected and fixed, and additional insulation protection is provided to prevent the inner cores of the first cable 2 and the second cable 3 from being damaged or polluted by the external environment, thereby protecting the stability and reliability of the line. By setting the second heat shrinkable sleeve 5, the dielectric layers of the first cable 2 and the second cable 3 can be connected and fixed, and additional insulation protection is provided. By setting the coaxial cable shielding layer 6, the shielding layers of the first cable 2 and the second cable 3 can be connected to each other to suppress the influence of external interference signals and improve the stability and reliability of signal transmission. By providing the third heat shrink sleeve 7, a certain mechanical protection effect can be provided to the coaxial cable shielding layer 6, and the coaxial cable shielding layer 6 can be insulated from the outside.

[0051] The fixing belt 8 is wound around the outside of the coil and is used to fix the coil to ensure its stability during use.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A broadband mid-feed antenna matching coil, characterized in that: including a magnetic core, a first cable, and a second cable; The first cable and the second cable are both wound around the magnetic core, the inner core of the first cable is connected in series with the inner core of the second cable, and the ratio of the number of windings of the first cable and the second cable is 3:6 to 4:6; The impedance of the first cable is 45 ohms to 55 ohms, the impedance of the second cable is 70 ohms to 80 ohms, the length of the first cable is 360 mm to 400 mm, and the length of the second cable is 485 mm to 525 mm.

2. The broadband center-fed antenna matching coil according to claim 1, characterized in that: The first cable and the second cable are tightly wound around the magnetic core so that the gap between adjacent turns of the cable is zero.

3. The broadband center-fed antenna matching coil according to claim 1, characterized in that: The magnetic core comprises three adjacently arranged magnetic rings, and the gap between adjacent magnetic rings is zero.

4. The broadband center-fed antenna matching coil according to claim 1, characterized in that: The ratio of the number of winding turns of the first cable to that of the second cable is 3:

5.

5. The broadband center-fed antenna matching coil according to claim 1, characterized in that: The impedance of the first cable is 50 ohms, and the impedance of the second cable is 75 ohms.

6. The broadband center-fed antenna matching coil according to claim 1, characterized in that: The length of the first cable is 380 mm, and the length of the second cable is 505 mm.

7. The wide-band center-fed antenna matching coil according to any one of claims 1 to 6, characterized in that: It also includes a first heat shrinkable sleeve, which is sleeved on the connection between the inner core of the first cable and the inner core of the second cable.

8. The wideband center-fed antenna matching coil according to any one of claims 1 to 6, characterized in that: It also includes a second heat shrinkable tube, one end of which is sleeved on the dielectric layer of the first cable, and the second end of which is sleeved on the dielectric layer of the second cable.

9. The wide-band center-fed antenna matching coil according to any one of claims 1 to 6, characterized in that: It also includes a coaxial cable shielding layer, one end of the coaxial cable shielding layer is connected to the shielding layer of the first cable, and the other end of the coaxial cable shielding layer is connected to the shielding layer of the second cable.

10. The broadband center-fed antenna matching coil according to claim 9, characterized in that: It also includes a third heat shrink sleeve, which is sleeved on the coaxial cable shielding layer.

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