CN208256906U - A Miniaturized Broadband High Gain Omnidirectional Antenna - Google Patents

Abstract

A miniaturized broadband high-gain omnidirectional antenna relates to wireless communication antenna equipment and technology, and consists of a multi-element composite array and an external feeder for feeding the multi-element composite array; the multi-element composite array comprises M groups of N-element sub-arrays which are uniformly arranged at the same interval in the same linear direction, and M groups of printed balanced double-guide feeders for feeding each N-element sub-array, wherein each N-element sub-array is formed by N ultra-wide oscillator units with the same shape and size in parallel, each ultra-wide band oscillator unit is formed by an upper oscillator arm, an oscillator lower arm and two parasitic branches, the ultra-wide band oscillator units are firstly constructed, then the N units form the wide band sub-array, balanced double-guide-wire feeding is adopted, the impedance is designed to be 25 omega instead of the conventional 50 omega, the broadband characteristic of the multi-element composite array is equivalent to that of a single oscillator, the gain is improved by nearly one time, and the basic premise is provided for. Further reducing welding spots, good intermodulation performance, light weight, low cost, suitability for batch production, miniaturization and high gain.

Description

A Miniaturized Broadband High Gain Omnidirectional Antenna

technical field

The utility model relates to wireless communication antenna equipment and technology, in particular to a miniaturized broadband high-gain omnidirectional antenna.

Background technique

Omnidirectional antenna, usually refers to a type of antenna with uniform radiation characteristics in the azimuth plane, it has a wide range of important uses in the field of wireless communication, typical scenarios such as communication base stations, radio and television towers, or terminals such as vehicles, aircraft, and wireless gateways equipment. First of all, since the position and orientation of the user equipment relative to the base station are arbitrary, the use of an omnidirectional antenna can not only ensure a good communication effect, but also reduce the size and cost of the equipment. In addition, considering the coverage and system capacity of the base station, the omnidirectional antenna must be high gain, wide bandwidth and high power. Furthermore, considering a large number of deployments and actual installations, omnidirectional antennas must also have the characteristics of miniaturization, low intermodulation, low cost, and suitable for mass production. To sum up, in the field of engineering, omnidirectional antennas with miniaturization, wide bandwidth, high gain, high efficiency, low cost, low intermodulation, and easy production have strong application requirements.

So far, all kinds of high-gain omnidirectional antennas have been realized by using half-wave dipoles in collinear or coaxial arrays. Due to factors such as application requirements, design difficulty, and size constraints, the common gain of high-gain omnidirectional antennas is 5~12dBi. Moreover, as the gain increases, the bandwidth will gradually decrease, that is, the gain and bandwidth are a pair of contradictions. For conventional high-gain broadband dipole arrays, metal tubes with thicker diameters are usually used as radiation units, and coaxial cables are used to construct feeder networks. This solution can overcome the contradiction between gain and bandwidth, and has a large power capacity, but has many solder joints, poor intermodulation, heavy weight, high cost, and difficulty in mass production. In contrast, the PCB printing scheme has the advantages of low intermodulation, high reliability, low cost, light weight, and suitable for mass production, but has lower power capacity, narrower impedance bandwidth, and narrower gain bandwidth. In view of the above characteristics, printed dipole arrays have been widely used in low-gain, narrow-band systems, such as terminal equipment. If the problem of high power and narrow bandwidth is solved, the printed vibrator array will become an ideal design solution for omnidirectional base stations. To sum up, the miniaturized high-gain broadband omnidirectional antenna has broad application prospects, but it still needs to break through many engineering bottlenecks, so it is still an important direction of antenna research.

Utility model content

In order to solve the above-mentioned technical problems, the utility model provides a miniaturized broadband high-gain omnidirectional antenna. Firstly, an ultra-wideband vibrator unit is constructed, and then N units are formed into a broadband sub-array, and a balanced dual wire feed is adopted. The impedance is designed to be 25Ω and Unconventional 50Ω, which makes its broadband characteristics comparable to that of a monooscillator, but its gain is nearly doubled, which provides the basic premise for achieving higher gain. Further, M such N-element sub-arrays are reorganized to form a higher-gain composite array, and coaxial cable feed is used to maintain the broadband characteristics of the sub-array, reduce solder joints, have good intermodulation performance, light weight, and low cost. Low, suitable for mass production, and has miniaturization, high gain effect.

In order to achieve the above technical objectives, the adopted technical solution is: a miniaturized broadband high-gain omnidirectional antenna, which consists of a multi-element composite array and an external feeder feeding the multi-element composite array;

The multi-element composite array includes M groups of N-element sub-arrays uniformly arranged in the same straight line and at the same distance, and M groups of N-element sub-arrays that are located on the center line of each N-element sub-array and feed each N-element sub-array. Printed balanced double-guide feeder, wherein, M≥2n, ⁿ =1, 2, 3..., at both ends of each N-element sub-array, there is a printed balanced double-guide feeder for the N-element sub-array Metallized via holes for short-circuiting the upper and lower feeder lines, and a central feeder hole for electrical connection between the external feeder line and the upper and lower feeder lines of the printed balanced double-conductor feeder line is provided in the center of each N-element sub-array;

The input impedance of the N-element sub-array is 25Ω, and N ultra-wide oscillator units of the same shape and size centered on the central feed hole are arranged side by side, wherein, N≥2; the ultra-wideband oscillator unit is arranged on the front of the PCB board. The upper arm of the vibrator, the lower arm of the vibrator arranged on the opposite side of the PCB and two parasitic branches, the upper arm of the vibrator is mirrored with the lower arm of the vibrator after moving down a distance T, the upper arm of the vibrator is connected to the upper feeder of the printed balanced double guide feeder line, the lower arm of the vibrator It is connected to the lower feeder of the printed balanced double guide feeder. The upper arm of the vibrator and the lower arm of the vibrator are both U-shaped vibrators. The openings of the upper arm of the vibrator and the lower arm of the vibrator are set opposite to each other. The wing arms on the upper and lower sides of the cross arm form a U-shaped structure. The wing arm is composed of a narrow arm section connected to the cross arm and a wide arm section at the other end. The center of the inside is provided with a notch that is sunken toward the outside;

A parasitic branch is provided on both sides between the outer side of the upper arm of the vibrator and the outer side of the lower arm of the vibrator. The two parasitic branches are not in contact and are symmetrically arranged on the front or back of the PCB board. Each parasitic branch is left and right Symmetrical, there are gaps between the inner side of the parasitic branch and the outer side of the upper arm of the vibrator and the outer side of the lower arm of the vibrator, and its outer side is flush with the outer edge of the narrow arm section. and the extension section, the center of the long strip section is connected to the sharp corner section, and the sharp corner section is connected to the extension section, and the long strip section is located in the gap surrounded by the wide arm section and the narrow arm section of the upper and lower arms of the vibrator. And the same shape as the gap, the pointed section is located in the space surrounded by the chamfered interior angle θ of the upper and lower arms of the vibrator, and is the same shape as the space, the extension section extends to the gap between the cross arms of the upper and lower arms of the vibrator ;

The external feeder is composed of a power divider, an impedance transformer, and a main feeder cable, and the power divider is divided into a group of two center feed holes and a printed balanced double-conductor feeder. The upper and lower feeders are electrically connected, and the one-to-two power divider is electrically connected to the main feeder cable through an impedance converter.

The upper and lower feeders of the printed balanced double-guide feeder described in the utility model are formed by cascading multiple conductor segments with unequal lengths and widths.

The external feeder of the utility model is composed of a 50Ω feeder cable, a 35Ω conversion section cable and a 50Ω main feeder cable. The upper and lower feeders of the balanced double-guide feeder are electrically connected, the center of the 50Ω split feeder cable is electrically connected to one end of the 35Ω conversion section cable, and the other end of the 35Ω conversion section cable is electrically connected to the 50Ω main feeder cable.

The upper arm of the vibrator and the lower arm of the vibrator described in the utility model form a half-wave vibrator, the length of each arm is 0.20-0.25 center wavelength λ _c , the ratio of the outer edge of the upper and lower two wide and narrow sections to the length of the upper arm of the vibrator is 0.45-0.75, the upper and lower The ratio of the opening distance between the two wide and narrow sections to the length of the upper arm of the vibrator is 0.25~0.35; the value of the chamfered internal angle θ ranges from ^15o to ^60o .

The notches described in the utility model are rectangular, triangular, circular grooves or other symmetrical structures.

The width-to-length ratio of the parasitic branches described in the utility model is 0.01-0.20.

The dielectric constant ε _r of the PCB board described in the utility model is 1-20, and the PCB board is various dielectric substrates including air.

In the utility model, the spacing between adjacent ultra-broadband oscillator units in the same N-element sub-array is d= (0.55 ~0.85) λ _c , and when the multi-element composite array composed of M N-element sub-arrays is uniformly arranged, M The element spacing of the multi-element composite array is N ‧( M- 1) ‧d .

The beneficial effects of the utility model are:

The positive progress effect of the utility model lies in that by taking the following measures: 1) Constructing the ultra-broadband vibrator unit; 2) The ultra-broadband vibrator forms an N-element sub-array, adopts printed balanced double-conductor feeding, and the impedance is designed to be 25Ω instead of the conventional 50Ω, which makes its broadband characteristics comparable to that of a single oscillator, but its gain is nearly doubled, which provides a basic premise for achieving higher gain; 3) N-element sub-arrays form a multi-element composite array, and use an external feeder, that is, a coaxial cable feed In order to maintain the broadband characteristics of the sub-array, the cables include three different impedance models, and the three types of cables are divided into two equal power dividers, impedance converters and main feeder cables, namely 50Ω feeder cables, 35Ω conversion section cables and 50Ω main feeder cables. Feeder cable; the low dispersion and low loss characteristics of the cable ensure the broadband high gain of the array. By adopting the above measures, the multi-element PCB vibrator composite array antenna of the present invention realizes near ultra-wideband (1.71-2.18GHz, VSWR≤2.5, BW=470MHz, 24.2%), high gain ( G =7.34~8.71 dBi), ideal omnidirectionality (out of roundness <2.4dB), low upper side lobe (SLL<-18dB), high lower side lobe (SLL>-12dB), and high efficiency ( η _A ≥70%) work. In addition, this solution also has the characteristics of small size (length -2.472× λ _c , width -0.177× λ _c ), simple feeding, low intermodulation, easy assembly and low cost, and is an ideal all-round solution for cellular base stations. antenna scheme.

In addition, this method also has the characteristics of novel thinking, clear principle, universal method, simple implementation, low cost, and suitable for mass production. The design and improvement of the terminal omnidirectional antenna is also applicable and effective.

Description of drawings

Figure 1 is a schematic diagram of the definition of the Cartesian coordinate system adopted by the antenna model of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 2 is a front view structural diagram of the upper arm and the lower arm of the miniaturized broadband high-gain omnidirectional antenna dipole.

Fig. 3 is a front view structural schematic diagram of a miniaturized broadband high-gain omnidirectional antenna ultra-broadband dipole unit.

Fig. 4 is a perspective structural schematic diagram of a miniaturized broadband high-gain omnidirectional antenna and an ultra-wideband dipole unit.

Fig. 5 is a schematic diagram of a front view structure of a two-element sub-array of a miniaturized broadband high-gain omnidirectional antenna.

FIG. 6 is a schematic perspective view of a two-element sub-array of a miniaturized broadband high-gain omnidirectional antenna.

FIG. 7 is a schematic diagram of a partially enlarged structure of a central feeding hole of a two-element subarray of a miniaturized broadband high-gain omnidirectional antenna.

FIG. 8 is a schematic diagram of a partially enlarged structure of metalized via holes at both ends of a two-element subarray of a miniaturized broadband high-gain omnidirectional antenna.

FIG. 9 is a schematic diagram of a front view structure of a multi-element composite array composed of two two-element sub-arrays of a miniaturized broadband high-gain omnidirectional antenna.

Fig. 10 is a schematic diagram of a front view structure of a miniaturized broadband high-gain omnidirectional antenna composed of two two-element sub-arrays forming a multi-component composite array and using an external feeder.

Figure 11 is a schematic diagram of the positional relationship between the external feeder of the multi-element composite array composed of two two-element sub-arrays of the miniaturized broadband high-gain omnidirectional antenna and the balanced double-guide feeder printed on the two sub-arrays.

Fig. 12 is a frequency characteristic curve of the input impedance Z _in of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 13 is the reflection coefficient | S ₁₁ | curve of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 14 is the standing wave ratio VSWR curve of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 15 is the gain pattern of the N-element sub-array at the center frequency f _c =1.90 GHz of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 16 is a frequency characteristic curve of the input impedance Z _in of the miniaturized broadband high-gain omnidirectional antenna.

Figure 17 is the VSWR curve of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 18 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _L =1.71 GHz.

Fig. 19 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _C =1.945 GHz.

Fig. 20 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _H =2.18 GHz.

Figure 21 shows the variation characteristics of the gain G of the miniaturized broadband high-gain omnidirectional antenna with frequency f .

Fig. 22 is a curve of H-plane out-of-roundness versus frequency f of a miniaturized broadband high-gain omnidirectional antenna.

Figure 23 shows the variation characteristics of the E-plane (vertical plane) half-power beamwidth HBPW with frequency f of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 24 is a variation curve of the efficiency η _A of the miniaturized broadband high-gain omnidirectional antenna with frequency f .

Fig. 25 is a schematic diagram of the distance between two two-element sub-arrays of the miniaturized broadband high-gain omnidirectional antenna.

Fig. 26 is a schematic diagram of the distance between two ternary sub-arrays of the miniaturized broadband high-gain omnidirectional antenna.

In the figure: 1. Multi-element composite array, 2. External feeder, 3. N-element sub-array, 4. Printed balanced double-guide feeder, 4-1. Printed upper feeder, 4-2. Printed lower feeder, 41. Metallized via hole, 42, central feed hole, 5, feeder cable, 6, transformation section cable, 7, main feed cable, 8, ultra-broadband vibrator unit, 81, vibrator upper arm, 811, cross arm, 811-1 , inner angle, 811-2, notch, 812, wing arm, 812-1, narrow arm section, 812-2, wide arm section, 82, vibrator lower arm, 83, parasitic branch, 831, long strip section, 832, Pointed section, 833, extension section.

The drawings in this paper are used to further explain and understand the utility model, and constitute a part of the description, and are used to explain the utility model together with specific embodiments of the utility model, but do not constitute a limitation or limitation to the utility model.

Detailed ways

Provide preferred embodiments of the utility model below in conjunction with accompanying drawing, to describe the technical solution of the utility model in detail. Here, the utility model will be described in detail with corresponding drawings. It should be noted that the preferred implementation examples described here are only used to illustrate and explain the utility model, and are not used to limit or limit the utility model.

The utility model aims to provide a miniaturization, wide frequency band, high gain, omnidirectional, low upper side lobe/high lower side lobe, high efficiency, low intermodulation, high reliability, simple structure and low cost for cellular communication , An omnidirectional base station antenna that is easy to produce, and provides a useful reference method for the design and improvement of omnidirectional antennas for low-gain, wide-narrowband terminal omnidirectional antennas.

A miniaturized broadband high-gain omnidirectional antenna is composed of a multi-element composite array 1 and an external feeder 2 feeding power to the multi-element composite array 1; the multi-element composite array can be designed according to requirements. The upper, lower, left and right sides proposed by the utility model are all limited by the direction shown in the figure.

The multi-element composite array 1 includes M groups of N-element sub-arrays 3 uniformly arranged in the same straight line and at the same distance, and N A group of printed balanced double guide feeders 4, wherein, M≥2n, ⁿ =1, 2, 3..., that is, the multi-element composite array contains at least two N-element sub-arrays to form an N·M-element composite array, each N The upper surface and the lower surface of the sub-array are respectively provided with upper and lower feeders of printed balanced double-guide feeder lines, and the printed balanced double-guide feeder lines are designed on the surface of the PCB board and electrically connected with the printed N-element sub-array.

Both ends of each N-element sub-array 3 are provided with a metallized via hole 41 that short-circuits the upper and lower feeder lines of the printed balanced double-guide feeder line 4 of the N-element sub-array 3, and the metallized via hole 41 passes through the upper and lower sides of the PCB board. On the surface, the upper and lower feeders of the printed balanced double-guided feeder 4 on the upper and lower surfaces of the PCB are short-circuited, and the upper and lower feeders for the external feeder 2 and the printed balanced double-guided feeder 4 are electrically connected at the center of each N-element subarray 3 The center feed hole 42 of the central feed hole 42 is to make the coaxial cable pass through the hole from below, the inner conductor is electrically connected with the upper feeder of the printed balanced double guide feeder 4, and the outer conductor is connected with the printed balanced double guide feeder 4 The lower feeder is electrically connected, or the central feeder hole 42 is to allow the coaxial cable to pass through the hole from above, the inner conductor is electrically connected to the lower feeder of the printed balanced double guide feeder 4, and the outer conductor is connected to the printed balanced double guide feeder 4's upper feeder is electrically connected.

The input impedance of the N-element sub-array 3 is 25Ω, and N ultra-broadband oscillator units 8 of the same shape and size centered on the central feed hole 42 are arranged side by side, wherein, N≥2; the ultra-broadband oscillator unit 8 is arranged on the front of the PCB board The upper arm 81 of the vibrator (upper surface), the lower arm 82 of the vibrator arranged on the reverse side (lower surface) of the PCB, and two parasitic branches 83 are composed. The upper arm 81 of the vibrator moves down a distance T and is mirror-symmetrical with the lower arm 82 of the vibrator. The distance T is is the thickness of the PCB board, the upper arm 81 of the vibrator is connected to the upper feeder of the printed balanced double guide feeder 4, the lower arm 82 of the vibrator is connected to the lower feeder of the printed balanced double guide feeder 4, the upper arm 81 of the vibrator and the lower arm 82 of the vibrator are both U The openings of the upper arm 81 of the vibrator and the lower arm 82 of the vibrator are arranged opposite to each other. The upper arm 81 of the vibrator or the lower arm 82 of the vibrator consists of a cross arm 811 in the middle and wing arms 812 symmetrically arranged on the upper and lower sides of the cross arm 811 to form a U-shaped structure. The arm 812 is composed of a narrow arm section 812-1 connected to the cross arm 811 and a wide arm section 812-2 at the other end. The width of the wide arm section 812-2 is greater than the width of the narrow arm section. The inner angle θ is chamfered inwardly, and the inner center of the cross arm 811 is provided with a notch 811 - 2 which is depressed outwardly.

A parasitic branch 83 is provided above and below (both sides) between the outer side of the upper arm 81 of the vibrator and the outer side of the lower arm 82 of the vibrator, that is, a parasitic branch 83 is provided above and below the gap between the upper arm 81 of the vibrator and the lower arm 82 of the vibrator. One parasitic branch 83, and two parasitic branches 83 are not in contact and are arranged symmetrically on the front or back of the PCB board. Each parasitic branch 83 is left-right symmetrical. There are gaps on the outside of 82, that is, the outer surface of the parasitic branch 83 is in the gap between the upper arm 81 of the vibrator and the lower arm 82 of the vibrator, and does not contact the outside of the two. The outer edge of 1 is flush, and the parasitic branch 83 is composed of an integrally formed long section 831, a sharp corner section 832 and an extension section 833, the center of the long strip section 831 is connected to the sharp corner section 832, and the pointed corner section 832 The corner is connected with an extension section 833, and the long section 831 is located in the gap surrounded by the wide arm section 812-2 and the narrow arm section 812-1 of the upper and lower arms of the vibrator, and has the same shape as the gap, and its size is slightly smaller than the gap , the sharp corner section 832 is located in the space enclosed by the chamfered inner angle θ of the upper and lower arms of the vibrator, and has the same shape as this space, and its size is slightly smaller than this space. The extension section 833 extends to between the cross arms 811 of the upper and lower arms of the vibrator In the gap, the extensions 833 of the two parasitic branches 83 are arranged in the gap between the cross arms 811 of the upper and lower arms of the vibrator facing but not in contact;

The external feeder 2 is composed of a splitter of equal power, an impedance converter and a main feeder cable, and the splitter of equal power is connected with the printed balanced dual through two center feed holes 42 as a group. The upper and lower feeders of the guide and feeder 4 are electrically connected, and the one-to-two power divider is electrically connected to the main feeder cable through an impedance converter.

If the number of N-element sub-arrays is 2, and the N-element sub-array is a two-element sub-array, then the external feeder needs a one-to-two power divider, an impedance converter and a main feeder cable, which is divided into two The output lines of the equal power divider are respectively electrically connected to the center feed hole 42 of a two-element subarray, and the input end of the equal power divider is connected to an impedance converter, and the input end of the impedance converter is connected to a The main feeder cable completes the external feeder connection and feeds power to the quaternary composite array.

If the number of N-element sub-arrays is 4, the N-element sub-array is a two-element sub-array, and the external feeder of the group needs to be prepared by combining two two-element sub-arrays into one group, and the external feeder line of this group needs to be divided into two Second-class power divider, an impedance converter and a main feeder cable, one is divided into the output lines of the second-class power divider to be electrically connected with the center feed hole 42 of an N-element sub-array respectively, and one is divided into two-class power divider The input end of the divider is connected to an impedance transformer, and the input end of the impedance transformer is connected to a main feeder cable, and then the main feeder cables of the two groups are respectively connected to an impedance transformer, and then the impedance transformer is connected to the final main feeder cable. On the feeder cable, complete the external feeder connection and feed power to the eight-element composite array.

If the number of N-element sub-arrays increases again, impedance converters and main feeder cables need to be added according to the above rules to complete all external feeder connections.

In addition, the external feeder 2 can be composed of a 50Ω feeder cable 5, a 35Ω conversion section cable 6 and a 50Ω main feeder cable 7, and the two ends of the 50Ω feeder cable 5 respectively pass through two central feeder holes 42 as a group It is electrically connected with the upper and lower feeders of the printed balanced double guide feeder 4, the center of the 50Ω distribution cable 5 is electrically connected with one end of the 35Ω conversion section cable 6, and the other end of the 35Ω conversion section cable 6 is connected with the 50Ω main feeder cable 7 electrical connection. When the two feeder cables are electrically connected to the center feed hole 42 of an N-element sub-array, they act as a power splitter, and the 35Ω conversion section cable 6 can replace the role of an impedance converter. Its installation design principle is the same as the above description. External feeder connections can be made according to the number of N-element sub-arrays.

The upper and lower feeders of the printed balanced double guide feeder 4 are formed by cascading multiple conductor segments with different lengths and widths, as shown in FIG. 5 .

The upper arm 81 of the vibrator and the lower arm 82 of the vibrator form a half-wave vibrator. The length of the upper arm 81 of the vibrator or the lower arm 82 of the vibrator is 0.20~0.25 center wavelength λ _c , and the ratio of the outer edges of the upper and lower wide and narrow sections to the upper arm of the vibrator is 0.45~0.75 , the ratio of the opening distance between the upper and lower wide and narrow sections to the length of the upper arm of the vibrator is 0.25~0.35; the range of the chamfered interior angle θ is ^15o ~ ^60o .

The notch 811-2 is a rectangular, triangular, circular groove or other symmetrical structure, and the symmetrical structure only needs to ensure that the center point on the inner side of the cross arm can be symmetrical up and down.

The width-to-length ratio of the parasitic branches 83 is 0.01-0.20.

The spacing between adjacent ultra-broadband oscillator units 8 in the same N-element sub-array is d= (0.55 ~0.85) λ _c , and when the multi-element composite array 1 composed of M N-element sub-arrays is uniformly arranged, the M multi-element The inter-element spacing of the composite array is N ‧( M-1) ‧d .

The dielectric constant of the PCB board is ε _r =1~20, and the PCB board is a variety of common dielectric substrates including air, such as Rogers series, Taconic series and Arlon series.

The miniaturized ultra-wideband high-gain omnidirectional antenna is characterized in that the design method of the miniaturized ultra-wideband high-gain omnidirectional antenna comprises the following steps:

Step 1, establish a space Cartesian coordinate system, as shown in Figure 1;

Step 2, constructing an ultra-broadband oscillator unit. On the XOZ plane, build a U-shaped structure with the opening facing upward along the +Z axis direction. The two arms of the U-shape are symmetrical to the left and right. The width of the two arms is wider at the top opening. sunken. Then, mirror the U shape along the X axis, and translate the mirror body along the Y axis for a distance T , so that the two arms of the vibrator are located on the front and back sides of the PCB, as shown in Figures 2 and 3. In addition, a pair of parasitic branches are attached in parallel to the outer sides of the U-shaped two arms. The branches are symmetrical up and down, left and right. The edges of the two arms are flush, and the middle of the branch protrudes inward into the gap between the two arms of the vibrator, as shown in Figure 3 and 4;

Step 3, constructing and printing the balanced dual conductor feeder and the N-element sub-array. The ultra-broadband oscillator unit in step 2 is translated and copied N times along the Z axis, so that the distance between two adjacent ultra-broadband oscillator units is d , forming an equally spaced N-element uniform linear array. Then, the printed balanced double-guide feeder is used to feed power in the middle of the N-element sub-array, and there are metallized vias at both ends of the N-element sub-array to short-circuit the upper and lower feeders of the printed balanced double-guide feeder; the printed balanced double-guide feeder is composed of It is formed by cascading multiple conductor segments with different lengths and widths. The upper and lower feeders of the printed balanced double-conductor feeder are respectively connected to the upper and lower arms of the N-element sub-array, as shown in Figures 5-8;

Step 4, construct the external feeder and multi-element composite array. Translate the N -element sub-array in step 3 along the Z -axis for a distance of N‧d , and copy the sub-array M times to form a composite array of ( N·M ) elements. Then, 2M feeder cables are used to connect the central feed holes of the ^{M N} -element subarrays respectively, and the 2M feeder cables are connected to another section of the impedance transformation section cable with a feed slot in groups of 2. Finally, connect a standard 50 ohm main feeder cable to the other end of each transformation section cable with a feeder slot, as shown in Figures 9~11.

Fig. 4 is a perspective structural schematic diagram of a miniaturized broadband high-gain omnidirectional antenna and an ultra-wideband dipole unit.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light-colored black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board;

Fig. 5 is a schematic diagram of a front view structure of a two-element sub-array of a miniaturized broadband high-gain omnidirectional antenna.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light-colored black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box in the center indicates the center feed hole, and the dotted line boxes at both ends indicate the metallization process. hole;

FIG. 6 is a schematic perspective view of a two-element sub-array of a miniaturized broadband high-gain omnidirectional antenna.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box in the center indicates the central feed hole, and the dotted line boxes at both ends indicate metallized vias ;

FIG. 7 is a schematic diagram of a partially enlarged structure of a central feeding hole of a two-element subarray of a miniaturized broadband high-gain omnidirectional antenna.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box indicates the central feed hole, and its aperture size is different on both sides of the printed feed line;

FIG. 8 is a schematic diagram of a partially enlarged structure of metalized via holes at both ends of a two-element subarray of a miniaturized broadband high-gain omnidirectional antenna.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box indicates the metallized via;

FIG. 9 is a schematic diagram of a front view structure of a multi-element composite array composed of two two-element sub-arrays of a miniaturized broadband high-gain omnidirectional antenna.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box in the center indicates the central feed hole, and the dotted line boxes at both ends indicate metallized vias ;

Fig. 10 is a schematic diagram of a front view structure of a miniaturized broadband high-gain omnidirectional antenna composed of two two-element sub-arrays forming a multi-component composite array and using an external feeder.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box indicates the central feed hole or metallized via hole; the thick and thick black solid lines indicate all levels The feeder cables, the black dots represent the cable connection points; the cables of all levels are routed along the center of the printed feeder line on the same side of the array, their outer skins are peeled off, the outer conductors are welded to each other, and finally connected to the printed circuit boards of the sub-array. System feeder welding.

Fig. 11 is a schematic diagram of the positional relationship between the distribution cable of the multi-element composite array formed by the two two-element sub-arrays of the miniaturized broadband high-gain omnidirectional antenna and the balanced double-guide feeder printed on the two sub-arrays.

Among them, the black line box indicates the upper arm of the PCB oscillator, which is located on the front of the PCB board; the light black line box indicates the lower arm of the PCB oscillator, which is located on the back of the PCB board; the dotted line box indicates the central feed hole or metalized via hole; the thin black solid line indicates two A feeder cable, the black dot indicates the cable connection point; the cable connection point is then connected to the transformation section cable.

Fig. 12 is a frequency characteristic curve of the input impedance Z _in of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna. Wherein, the horizontal axis (X axis) is the frequency f in GHz; the vertical axis (Y axis) is the impedance Z _{in in} Ω; the solid line represents the real part R _in , and the dotted line represents the imaginary part X _in . As can be seen from the figure, in the frequency band of 1.71~2.18GHz, the ranges of real and imaginary parts are +20~+28Ω and -6~+6Ω, respectively, which have obvious broadband impedance characteristics.

Fig. 13 is the reflection coefficient | S ₁₁ | curve of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna. Wherein, the horizontal axis (X axis) is the frequency f , the unit is GHz; the vertical axis (Y axis) is the amplitude | S ₁₁ | of S ₁₁ , and the unit is dB. It can be seen from the picture that the antenna achieves good impedance matching in the LTE frequency band (1.71~2.18GHz, BW=470MHz), the reflection coefficient | S ₁₁ |≤-15, the lowest can reach -26.3dB, and the relative bandwidth is 24.2 %, basically realized the ultra-broadband work.

Fig. 14 is the standing wave ratio VSWR curve of the N-element sub-array of the miniaturized broadband high-gain omnidirectional antenna. Among them, the horizontal axis (X axis) is frequency f in GHz; the vertical axis (Y axis) is VSWR. As shown in the figure, the antenna achieves good impedance matching in the LTE frequency band (1.71~2.18GHz, BW=470MHz), the standing wave ratio VSWR≤1.43, the minimum reaches 1.1, and the relative bandwidth is 24.2%, which basically realizes ultra-wideband operation.

Fig. 15 is the gain pattern of the N-element sub-array at the center frequency f _c =1.90 GHz of the miniaturized broadband high-gain omnidirectional antenna. Among them, the solid line represents the H plane, and the dotted line represents the E plane; the H plane is close to a perfect circle, indicating that the omnidirectionality is good; the E plane has a narrow beam, a gain of G =4.81dBi, and a low side lobe (the normalized value is about -19dB) .

Fig. 16 is a frequency characteristic curve of the input impedance Z _in of the miniaturized broadband high-gain omnidirectional antenna. Wherein, the horizontal axis (X axis) is the frequency f in GHz; the vertical axis (Y axis) is the impedance Z _{in in} Ω; the solid line represents the real part R _in , and the dotted line represents the imaginary part X _in . As can be seen from the figure, in the frequency band of 1.71~2.18GHz, the ranges of real and imaginary parts are +25~+72Ω and -35~+20Ω respectively, which have obvious broadband impedance characteristics.

Figure 17 is the VSWR curve of the miniaturized broadband high-gain omnidirectional antenna. Among them, the horizontal axis (X axis) is frequency f in GHz; the vertical axis (Y axis) is VSWR. It can be seen from the figure that the antenna achieves good impedance matching in the LTE frequency band (1.71~2.18GHz, BW=470MHz), the standing wave ratio VSWR≤2.5, the minimum reaches 1.20, and the relative bandwidth is 24.2%, which basically realizes ultra-wideband work.

Fig. 18 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _L =1.71 GHz. Among them, the solid line represents the H plane, and the dotted line represents the E plane; the H plane is close to a perfect circle, indicating good omnidirectionality; the E plane has a narrow beam, and the gain G = 7.14dBi; there is no upper side lobe, and the interference to adjacent cells is low; the lower side The lobe level is high (the normalized value is about -12dB), which is conducive to improving the coverage under the station.

Fig. 19 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _C =1.945 GHz. Among them, the solid line represents the H plane, and the dotted line represents the E plane; the H plane is close to a perfect circle, indicating that the omnidirectionality is good; the E plane has a narrow beam, and the gain G = 8.69dBi; the upper side lobe level is low (the normalized value is about -18dB), which has little interference to neighboring cells; the lower side lobe level is higher (normalized value is about -12dB), which is conducive to improving the coverage under the station.

Fig. 20 is a gain pattern diagram of a miniaturized broadband high-gain omnidirectional antenna at the frequency point f _H =2.18 GHz. Among them, the solid line represents the H plane, and the dotted line represents the E plane; the H plane is close to a perfect circle, indicating that the omnidirectionality is good; the E plane has a narrow beam, and the gain G = 8.44dBi; the upper side lobe level is low (the normalized value is about -18dB), which has little interference to neighboring cells; the lower side lobe level is higher (normalized value is about -11dB), which is conducive to improving the coverage under the station.

Figure 21 shows the variation characteristics of the gain G of the miniaturized broadband high-gain omnidirectional antenna with frequency f . Wherein, the horizontal axis (X axis) is the frequency f , and the unit is GHz; the vertical axis (Y axis) is the gain G , and the unit is dBi. It can be seen from the figure that the variation range of the in-band gain G is: 7.34~8.71 dBi, the gain is higher, and the in-band flatness is better.

Fig. 22 is a curve of H-plane out-of-roundness versus frequency f of a miniaturized broadband high-gain omnidirectional antenna. Among them, the horizontal axis (X axis) is the frequency f , the unit is GHz; the vertical axis (Y axis) is the out-of-roundness, the unit is degree dB. It can be seen from the figure that in the whole frequency band, the out-of-roundness (omnidirectionality or uniformity) of the pattern on the horizontal plane (H plane) is less than 2.4dB, which has a relatively ideal horizontal uniform radiation characteristic.

Figure 23 shows the variation characteristics of the E-plane (vertical plane) half-power beamwidth HBPW with frequency f of the miniaturized broadband high-gain omnidirectional antenna. Among them, the horizontal axis (X axis) is the frequency f , and the unit is GHz; the vertical axis (Y axis) is the beam width, and the unit is degree (deg); the solid line is the Phi=0° plane, and the dotted line is the Phi=90° plane. It can be seen from the figure that the in-band half-power wave widths of the two planes are: HPBW=18.2 ^o ~25 ^o , HPBW=17.5 ^o ~24.2 ^o , the wave width of the E plane is narrower, and the difference in the band is small. In addition, the difference in wave width between the two E-planes with Phi=0° and 90° is small, indicating that the out-of-roundness of the H-plane is ideal.

Fig. 24 is a variation curve of the efficiency η _A of the miniaturized broadband high-gain omnidirectional antenna with frequency f . Among them, the horizontal axis (X axis) is the frequency f in GHz; the vertical axis (Y axis) is the efficiency. It can be seen from the figure that the antenna efficiency η _A ≥ 70% (typical value > 82%) in the entire frequency band, the efficiency is ideal.

Fig. 25 is a schematic diagram of the distance between two two-element sub-arrays of the miniaturized broadband high-gain omnidirectional antenna.

Among them, d ₁ is the spacing between two adjacent ultra-broadband oscillator units in the two-element sub-array, and the element spacing of the multi-element composite array composed of two two-element sub-arrays is d ₂ , when S ₁ = S ₂ , d ₂ = 2d ₁ , when S ₁ < S ₂ , d ₂ > 2d ₁ .

Fig. 26 is a schematic diagram of the distance between two ternary sub-arrays of the miniaturized broadband high-gain omnidirectional antenna.

Among them, d ₁ is the spacing between two adjacent ultra-broadband oscillator units in the two-element sub-array, and the element spacing of the multi-element composite array composed of two two-element sub-arrays is d ₂ , when S ₁ = S ₂ , d ₂ = 3d ₁ , when S ₁ < S ₂ , d ₂ >3d ₁ .

The positive progress effect of the utility model lies in that by taking the following measures: 1) Constructing the ultra-broadband vibrator unit; 2) The ultra-broadband vibrator forms an N-element sub-array, adopts balanced dual wire feed, and the impedance is designed to be 25Ω instead of the conventional 50Ω, The gain is nearly doubled, but the bandwidth is basically unchanged; 3) N-element sub-arrays form a composite array, which is fed by coaxial cables. The low dispersion and low loss characteristics of the cables ensure the wideband high gain of the array. By adopting the above measures, the N·M element PCB oscillator composite array antenna of the present utility model realizes near ultra-wideband (1.71-2.18GHz, VSWR≤2.5, BW=470MHz, 24.2%), high gain ( G = 7.34~8.71 dBi), ideal omnidirectionality (out of roundness<2.4dB), low upper side lobe (SLL<-18dB), high lower side lobe (SLL>-12dB), and high efficiency ( η _A ≥70% )Work. In addition, this scheme also has the characteristics of small size (length -2.472× λ _c , width -0.177× λ _c in the case of two binary elements), simple feeding, low intermodulation, convenient assembly and low cost, etc. An ideal omnidirectional antenna solution for cellular base stations.

In addition, this method also has the characteristics of novel thinking, clear principle, universal method, simple implementation, low cost, and suitable for mass production. The design and improvement of the terminal omnidirectional antenna is also applicable and effective.

The above are only preferred examples of the present utility model, and are not intended to limit or limit the present utility model. For researchers or technicians in the field, the utility model can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model shall be included in the scope of protection declared by the utility model.

Claims (8)

1. A miniaturized broadband high-gain omnidirectional antenna is composed of a multi-element composite array (1) and an external feeder (2) feeding the multi-element composite array (1), and is characterized in that:

the multi-element composite array (1) comprises M groups of N-element sub-arrays (3) which are uniformly arranged at the same interval in the same linear direction, and M groups of printed balanced dual-conductive feed lines (4) which are positioned on the arrangement central line of each N-element sub-array (3) and feed each N-element sub-array (3), wherein M is more than or equal to 2ⁿN =1, 2, 3 … …, and each N-element subarray (3) has N-elements at both ends thereofThe upper feeder line and the lower feeder line of the printed balanced double-conductor feeder line (4) of each subarray (3) are short-circuited through metalized holes (41), and a central feed hole (42) used for electrically connecting the external feeder line (2) with the upper feeder line and the lower feeder line of the printed balanced double-conductor feeder line (4) is formed in the center of each N-element subarray (3);

the input impedance of the N-element subarray (3) is 25 omega, and N ultra-wideband oscillator units (8) which are same in shape and size and take a central feed hole (42) as a center are formed in parallel, wherein N is more than or equal to 2; the ultra-wideband oscillator unit (8) consists of an upper oscillator arm (81) arranged on the front side of a PCB, a lower oscillator arm (82) arranged on the back side of the PCB and two parasitic branches (83), the upper oscillator arm (81) is in mirror symmetry with the lower oscillator arm (82) after moving downwards by a distance T, the upper oscillator arm (81) is connected with an upper feeder line printed with a balanced double-conductor feeder line (4), the lower oscillator arm (82) is connected with a lower feeder line printed with the balanced double-conductor feeder line (4), the upper oscillator arm (81) and the lower oscillator arm (82) are both U-shaped oscillators, openings of the upper oscillator arm (81) and the lower oscillator arm (82) are oppositely arranged, the upper oscillator arm (81) or the lower oscillator arm (82) consists of a cross arm (811) in the middle part and wing arms (812) symmetrically arranged on the upper side and the lower side of the cross arm (811), and the wing arms (812) consist of a narrow arm section (812-1) connected with the cross arm (811) and a wide arm section (812-, the two outer ends of the cross arm (811) are chamfered at an inner angle theta in the inner direction, and the inner center of the cross arm (811) is provided with a notch (811-2) which is concave towards the outer direction;

two parasitic branches (83) are respectively arranged on two sides between the outer side of the upper arm (81) of the vibrator and the outer side of the lower arm (82) of the vibrator, the two parasitic branches (83) are not in contact with each other and are symmetrically and jointly arranged on the front surface of a PCB (printed circuit board) or the back surface of the PCB, each parasitic branch (83) is in bilateral symmetry, gaps are respectively formed between the inner edges of the parasitic branches (83) and the outer sides of the upper arm (81) of the vibrator and the lower arm (82) of the vibrator, the outer edges of the parasitic branches are flush with the outer edges of the narrow arm sections (812-1), each parasitic branch (83) is composed of a long strip section (831), a sharp corner section (832) and an extension section (833) which are integrally formed, the center of the long strip section (831) is connected with the sharp corner section (832), the sharp corner of the sharp corner section (832) is connected with the extension section (833), and the long strip section (831) is positioned in the gap formed by the wide arm section (812-2, and the shape is the same as the gap, the sharp-angled section (832) is positioned in the space enclosed by the inverted internal angle theta of the upper arm and the lower arm of the vibrator, and the shape is the same as the space shape, and the extension section (833) extends into the gap between the cross arms (811) of the upper arm and the lower arm of the vibrator;

the external feeder (2) consists of a power divider, an impedance converter and a main feed cable, wherein the power divider is divided into two parts, the power divider is electrically connected with the upper and lower feeders of the printed balanced double-guide feeder (4) through two central feed holes (42) which are a group, and the power divider is divided into two parts and is electrically connected with the main feed cable through the impedance converter.

2. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the upper feeder line and the lower feeder line of the printed balanced double-conductor feeder line (4) are formed by cascading a plurality of sections of conductor sections with different lengths and widths.

3. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the external feeder (2) is composed of a 50 omega branch feeder cable (5), a 35 omega conversion section cable (6) and a 50 omega main feeder cable (7), two ends of the 50 omega branch feeder cable (5) are respectively electrically connected with an upper feeder line and a lower feeder line of the printed balanced double-guide feeder line (4) through two central feed holes (42) which are in a group, the center of the 50 omega branch feeder cable (5) is electrically connected with one end of the 35 omega conversion section cable (6), and the other end of the 35 omega conversion section cable (6) is electrically connected with the 50 omega main feeder cable (7).

4. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the oscillator upper arm (81) and the oscillator lower arm (82) form a half-wave oscillator, and the length of each arm is 0.20-0.25 of central wavelengthλ _c The length ratio of the outer edges of the upper and lower wide and narrow sections to the upper arm of the vibrator is 0.45-0.75, and the opening between the upper and lower wide and narrow sectionsThe length ratio of the distance to the upper arm of the vibrator is 0.25-0.35; inverted internal angleθValue range of 15^o~60^o。

5. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the notch (811-2) is rectangular, triangular, circular groove or other symmetrical structures.

6. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the width-length ratio of the parasitic branch (83) is 0.01-0.20.

7. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the dielectric constant epsilon of the PCB_rAnd = 1-20, the PCB is various dielectric substrates including air.

8. A miniaturized wideband high gain omni directional antenna as claimed in claim 1, wherein: the distance between adjacent ultra-wideband vibrator units (8) in the same N-element subarray isd=(0.55 ~0.85)λ _c When M multi-element composite arrays (1) composed of N-element sub-arrays are uniformly arranged, the array element spacing of the M multi-element composite arrays (1) is equal toN‧(M-1)‧d。