CN213959104U

CN213959104U - Miniaturized base station antenna built-in cavity duplexer

Info

Publication number: CN213959104U
Application number: CN202023264980.6U
Authority: CN
Inventors: 陈国梁
Original assignee: Hengerwei Technology Suzhou Co ltd
Current assignee: Hengerwei Technology Suzhou Co ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-08-13
Anticipated expiration: 2030-12-30

Abstract

The utility model discloses a miniaturized base station antenna built-in cavity duplexer, which comprises a cavity, a radio frequency cable, an upper cover plate and a lower cover plate, wherein the upper cover plate is arranged at the top of the cavity, and the lower cover plate is arranged at the bottom of the cavity; a first filter and a second filter are arranged in the cavity and are connected through a common cavity; the first filter and the second filter are both composed of a plurality of resonators, the common cavity is a resonator, and the resonator is composed of a resonance rod and a loading capacitor connected to the resonance rod; the number of the radio frequency cables is three, one end of each radio frequency cable is respectively connected with the first filter, the second filter and the common cavity, and the other end of each radio frequency cable is led out of the cavity. The utility model discloses a common chamber merges two wave filters into a duplexer, and the isolation of duplexer can be improved to the form in this kind of common chamber, reduces the mutual interference between two wave filters, simple structure moreover, easily production.

Description

Miniaturized base station antenna built-in cavity duplexer

Technical Field

The utility model belongs to the technical field of communication, in particular to built-in cavity duplexer of base station antenna.

Background

With the rapid development of mobile communication technology, base station antennas and radio frequency devices have become the focus of attention. Under the push of increasing market and demand, communication technology is continuously showing new, so that the development of the communication industry has new development requirements and directions. With the miniaturization, light weight, integration, low cost and higher gain of the base station antenna, higher and higher requirements are put forward on the radio frequency device built in the base station antenna. Wherein the base station antenna built-in duplexer becomes the most critical part of the above requirements. The duplexer with the built-in base station antenna is used for array frequency multiplexing and frequency selection of the base station antenna, and plays a crucial role in miniaturization and integration of the base station antenna. The performance of the duplexer also affects the overall performance of the antenna, and the low loss and high isolation of the duplexer can bring higher gain and isolation to the antenna. With the internal structure of the antenna becoming more and more complex and the internal space becoming more and more compact, higher requirements are put on the volume and weight of the base station duplexer. In the current products in the mobile communication market, the high performance and small volume of the duplexer are always difficult to balance.

Disclosure of Invention

The utility model aims at providing a cavity duplexer is put to miniaturized base station antenna to realize little volume, low-loss, high isolation and the high intermodulation of duplexer.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a miniature base station antenna built-in cavity duplexer comprises a cavity, a radio frequency cable, an upper cover plate and a lower cover plate, wherein the upper cover plate is arranged at the top of the cavity, and the lower cover plate is arranged at the bottom of the cavity; a first filter and a second filter are arranged in the cavity and are connected through a common cavity; the first filter and the second filter are both composed of a plurality of resonators, a common cavity is a resonator, and the resonator is composed of a resonance rod and a loading capacitor connected to the resonance rod; the number of the radio frequency cables is three, one end of each radio frequency cable is respectively connected with the first filter, the second filter and the common cavity, and the other end of each radio frequency cable is led out of the cavity.

Furthermore, metal connecting ribs are arranged between adjacent resonators and are respectively connected with the resonance rods of the adjacent resonators.

Furthermore, the metal connecting ribs are arranged between one group or multiple groups of adjacent resonators.

Furthermore, a debugging hole is formed in the loading capacitor, and the debugging hole is a through hole.

Further, the spacing between adjacent resonators is adjustable.

Further, the radio frequency cable is an RG-401 radio frequency cable.

Has the advantages that: the utility model discloses a common chamber merges two wave filters into a duplexer, and the isolation of duplexer can be improved to the form in this kind of common chamber, reduces the mutual interference between two wave filters, simple structure moreover, easily production. The utility model discloses simple structure, simple inner structure not only can obtain higher third-order intermodulation, can also improve the production uniformity to reduction in production cost. Compared with the prior art, the utility model has the advantages of it is following:

1. low loss, high isolation: the insertion loss of the duplexer is less than-0.5 dB, the return loss is less than-20 dB, and the mutual isolation between the two pass bands is less than-32 dB;

2. high intermodulation: the utility model has simple structure, good effect of third-order intermodulation test, the third-order intermodulation is less than-155 dBc (2 multiplied by 20W), and the intermodulation passing rate is high;

3. high mass productivity, low cost: the utility model discloses simple structure, easily mass production, the through rate is high, and is with low costs.

Drawings

Fig. 1 is a schematic structural diagram of the miniaturized base station antenna built-in cavity duplexer of the present invention;

fig. 2 is a disassembly schematic diagram of the miniaturized base station antenna built-in cavity duplexer of the present invention;

FIG. 3 is a schematic diagram of the internal structure of the chamber;

FIG. 4 is a schematic view of a weld of a radio frequency cable;

fig. 5 is a simulation curve of the duplexer of the embodiment;

FIG. 6 is a test curve (698-862MHz band) of the duplexer of the embodiment;

FIG. 7 shows a test curve (880-960MHz band) of the duplexer of the embodiment.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

As shown in fig. 1 to 3, the cavity duplexer with a built-in miniaturized base station antenna of the present invention includes a cavity 2, a radio frequency cable 4, an upper cover plate 1 disposed on the top of the cavity 2, and a lower cover plate 3 disposed on the bottom of the cavity 2; two filters, namely a first filter and a second filter, are arranged in the cavity 2, and the first filter and the second filter are connected through a common cavity 9 to form a duplexer.

The first filter and the second filter are both composed of several resonators, and the common cavity 9 is one resonator.

The resonator consists of a resonant rod 6 and a loading capacitor 5 connected to the resonant rod 6. The filter syntonizer of constituteing by loading electric capacity 5 and resonance bar 6 has higher quality factor the utility model discloses on 780 MHz's frequency at place, can reach more than 1300, under equal filter order, can obtain lower loss. According to the theoretical formula: f is 1/(2pi × sqrt (L × C)), where f is the resonance frequency, C is the inductance, and L is the capacitance. The thickness and the width of the resonance rod 6 are reduced, namely the L is increased, so that the eigenfrequency of the resonator can be reduced under the same cavity volume; at the same frequency, a smaller volume can be obtained without a drastic deterioration of the quality factor. According to the theoretical formula: f is 1/(2pi × sqrt (L × C)), where f is the resonance frequency, C is the inductance, and L is the capacitance. The relative areas of the loading capacitor 5 and the diameters of the cavity wall and the upper and lower cover plates are increased, namely C is increased, so that the eigenfrequency of the resonator can be reduced under the same cavity volume; at the same frequency, a smaller volume can be obtained without a drastic deterioration of the quality factor.

The number of the radio frequency cables 4 is three, one end of each radio frequency cable is respectively connected with the first filter, the second filter and the common cavity 9, and the other end of each radio frequency cable is led out of the cavity 2. The resonator farthest from the common cavity 9 in the first filter is connected to the radio frequency cable 4, the resonator farthest from the common cavity 9 in the second filter is connected to the radio frequency cable 4, as shown in fig. 4, one end of the first radio frequency cable 4 is welded to the resonance rod of the resonator at the leftmost end of the first filter, the welding point is a, one end of the second radio frequency cable 4 is welded to the loading capacitor 5 of the common cavity 9, the welding point is B, one end of the third radio frequency cable 4 is welded to the resonance rod of the resonator at the rightmost end of the second filter, and the welding point is C.

And a metal connecting rib 7 is arranged between the adjacent resonators, and the metal connecting rib 7 is respectively connected with the resonance rod 6 of the adjacent resonator. The metal connecting ribs 7 are arranged between one or more groups of adjacent resonators, for example, in fig. 2, no metal connecting rib 7 is arranged between the two resonators on the rightmost side, and metal connecting ribs 7 are arranged between the other resonators. Theoretically, there will be coupling between connected resonators and no coupling between unconnected resonators. However, in practical design, coupling between the unconnected resonators may also occur, and the coupling between the unconnected resonators is called parasitic coupling. In conventional filter designs, such parasitic coupling is very weak and needs to be avoided, and too strong parasitic coupling may affect the overall performance of the filter, making the filter unable to meet the desired specifications. The utility model discloses in, the linear arrangement who has adopted the syntonizer produces stronger parasitic coupling to can strengthen and control the size of parasitic coupling with metal even muscle 7 between the syntonizer, and can control its position in a flexible way, make this stronger parasitic coupling can produce a stronger transmission zero point, increase the rectangular coefficient of wave filter on the passband left side of wave filter or the right. Thus, by combining the two filters into a duplexer, a higher degree of isolation can be achieved. Theoretically, with this structure, an N-th order filter can generate (N-1) transmission zeros. Compared with the traditional product, more transmission zero points and higher out-of-band rejection can be obtained. More transmission zeros also means that higher performance can be achieved with fewer filter orders, which greatly reduces the size of the filter. The method has great advantages in the number of transmission zero points, and also has great advantages in the strength, capacity and sensibility of the transmission zero points. Generally speaking, the transmission zero on the left side of the filter passband is capacitive; the transmission zero on the right side of the filter passband is inductive. The inductance can be generated by directly connecting the two resonators or satisfying a certain coupling distance, the capacitance can be generated by adding a capacitive coupling structure between the two resonators, and the generation of the capacitive zero point is relatively troublesome in structure. The utility model discloses a structure can realize producing capacitive or inductive transmission zero point in arbitrary department outside the wave filter passband, and the position at zero point is nimble controllable more, need not increase extra capacitive coupling structure again, very big reduction structural pressure and the cost pressure that capacitive coupling brought, uniformity and the reliability that can effectual improvement production.

A debugging hole 8 is formed in the loading capacitor 5, and the debugging hole 8 is a through hole. The tuning holes 8 are used to adjust the frequency of the filter, increasing the producibility of the product.

The spacing 10 between adjacent resonators is adjustable to control the coupling bandwidth of the filter to operate in the desired frequency band.

The present invention will be further described with reference to the following examples.

Examples

In this embodiment, the working frequency of the duplexer is 698MHz-862MHz/880MHz-960 MHz. 698-862MHz band, 5-order filter composed of 5 resonators; in the frequency band of 880MHz-960MHz, a 5-order filter is also adopted and consists of 5 resonators. The resonators are connected by the metal connecting ribs 7, so that the overall structural strength of the duplexer can be enhanced, the parasitic coupling between non-adjacent resonators can be enhanced, and a stronger transmission zero point is generated. 698MHz-862MHz frequency band, connect 5 resonators with the metal tie bar, can produce very strong parasitic coupling like this, produce the strong transmission zero point near the passband, and through adjusting the height of the metal tie bar, make the transmission zero point produced just in time fall on the right of the passband. The height of the metal connecting ribs is adjusted, and the positions of transmission zero points generated by parasitic coupling can also be adjusted to be distributed in sequence, so that a better stop band inhibition effect is achieved. The 4 cross couplings generated by the 698MHz-862MHz band are all placed on the right side of the passband according to the index requirement. In the frequency range of 880MHz to 960MHz, the first 4 resonators are connected by metal connecting ribs, the height of the metal connecting ribs is adjusted, the generated transmission zero point is just positioned on the left side of the passband, and the positions of the transmission zero points are adjusted and distributed in sequence, so that a better stop band inhibition effect is achieved. According to the requirement of indexes, 3 cross couplings generated by the 880MHz-960MHz frequency band are placed on the left side of the passband, and a weaker cross coupling is also positioned on the right side of the passband, so that the influence of the cross coupling on the right side on the overall performance of the duplexer is very small, and the position and the polarity of the duplexer do not need to be adjusted. The benefit of cross-coupling with parasitic coupling: 1: the parts required by adding cross coupling are reduced, so that the filter structure is simpler; 2: the polarity of the cross coupling can be adjusted by the intensity of the parasitic coupling, so that not only inductive coupling but also capacitive coupling can be generated, and the position of the generated cross coupling can be adjusted at will, and stronger cross coupling 3: the N-order filter can generate (N-1) cross couplings, so that the filter can obtain better rectangular coefficients, and the order of the filter can be saved under the same index requirement, thereby not only greatly reducing the size of the filter, but also reducing the insertion loss of the filter and ensuring that the performance of the filter is better.

In this embodiment, the thickness and the width of the resonant rod 6 are both 2.5mm, the distance between the loading capacitor 5 and the inner wall of the cavity is 1.5mm, and the distances between the loading capacitor 5 and the upper cover plate 1 and between the loading capacitor 5 and the lower cover plate 3 are both 0.5 mm. Thus, the width and height dimensions of the filter can be greatly reduced at the same eigenfrequency, and the quality factor is not greatly deteriorated.

In this embodiment, the diameter of the tuning hole 8 is 4mm-5mm, and a tuning screw can be added to the upper cover plate of the duplexer to adjust the resonant frequency of each resonator, thereby increasing the producibility.

In the embodiment, the common cavity 9 is adopted to connect the filter with the frequency band of 698MHz-862MHz with the filter with the frequency band of 880MHz-960MHz to form the duplexer, so that the mutual influence between the two filters can be reduced to a great extent, the isolation of the duplexer can be improved, the structure of the duplexer is simpler, the passing rate of third-order intermodulation is improved, and the production cost is reduced.

In the embodiment, the RG-401 radio frequency cable is used as an input/output port to be connected with three ports of the duplexer, and as the RG-401 radio frequency cable is mostly used in the base station antenna to connect with a complex feed network, the port form can be better connected with the feed network in the antenna, and mismatching generated in the switching process of various ports is avoided.

In this embodiment, the overall dimension of the duplexer is: 135.25X 57X 19 (length X width X height, unit: mm, without mounting hole size) is reduced by about 1/3 compared to a similar product.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The utility model provides a cavity duplexer is built-in to miniaturized base station antenna which characterized in that: the radio frequency cable antenna comprises a cavity (2), a radio frequency cable (4), an upper cover plate (1) and a lower cover plate (3), wherein the upper cover plate (1) and the lower cover plate (3) are respectively arranged at the top of the cavity (2); a first filter and a second filter are arranged in the cavity (2), and the first filter and the second filter are connected through a common cavity (9); the first filter and the second filter are both composed of a plurality of resonators, a common cavity (9) is a resonator, and the resonator is composed of a resonance rod (6) and a loading capacitor (5) connected to the resonance rod (6); the number of the radio frequency cables (4) is three, one end of each radio frequency cable is respectively connected with the first filter, the second filter and the common cavity (9), and the other end of each radio frequency cable is led out of the cavity (2).

2. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: and metal connecting ribs (7) are arranged between the adjacent resonators, and the metal connecting ribs (7) are respectively connected with the resonance rods (6) of the adjacent resonators.

3. The miniaturized base station antenna built-in cavity duplexer of claim 2, wherein: the metal connecting ribs (7) are arranged between one group or multiple groups of adjacent resonators.

4. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: a debugging hole (8) is formed in the loading capacitor (5), and the debugging hole (8) is a through hole.

5. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: the spacing (10) between adjacent resonators is adjustable.

6. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: the radio frequency cable (4) is an RG-401 radio frequency cable.

7. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: the thickness and the width of the resonance rod (6) are both 2.5 mm.

8. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: the distance between the loading capacitor (5) and the inner wall of the cavity is 1.5mm, and the distances between the loading capacitor (5) and the upper cover plate (1) and between the loading capacitor (5) and the lower cover plate (3) are 0.5mm respectively.

9. The miniaturized base station antenna built-in cavity duplexer of claim 1, wherein: the first filter is a 5-order filter and consists of 5 resonators; the second filter is also a 5-order filter and consists of 5 resonators.