A TD-LTE smart antenna for use in the 3500MHz frequency band

Abstract

The present invention relates to the field of communication antenna technology, and specifically to a TD-LTE smart antenna used in a frequency band near 3500MHz, comprising a metal reflector, a radiation unit, a metal isolation wall, a metal isolation strip, and a feed network; the radiation unit, the metal isolation wall, and the metal isolation strip are fixedly installed on the front of the metal reflector, and the feed network is welded and connected to each radiation unit, respectively, and installed on the front or back of the metal reflector. A low-stripped wide-band patch radiation unit with a height of only 1 / 8 of the wavelength of the working center frequency is selected to reduce the antenna beam width. At the same time, a specific metal isolation piece is designed as a radiation boundary, so that the high-frequency band antenna can obtain a unit beam with a 65° wavelength width with superior performance while adopting an array arrangement of conventional low-frequency smart antennas. On this basis, relevant measures are adopted to strictly control the consistency of the amplitude and phase of each radio frequency port, so that the high-frequency band smart antenna can obtain a synthetic beam of superior performance for services, broadcasts, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of communication antennas, and in particular to a TD-LTE smart antenna used in a frequency band near 3500 MHz. Background Art

[0002] Based on 3GPP Long Term Evolution (TD-LTE), it is a new generation of broadband mobile communication wireless access technology. Compared with the access technology of existing 2G and 3G mobile communication systems, it has the characteristics of high transmission rate, small transmission delay, and high service quality assurance. Smart antenna technology is one of the key technologies of TD-LTE system. It introduces the space division multiple access (SDMA) method, and uses the difference in signal transmission to distinguish the same frequency or time slot, so as to maximize the use of limited channel resources. Compared with non-directional antennas, smart antennas point the shaped beam to the user, improve the gain of the uplink and downlink, reduce the interference between users, and improve the signal-to-noise ratio and system capacity. A pair of high-performance smart antennas will greatly help the coverage quality of TD-LTE network.

[0003] At present, the existing smart antenna products in the domestic market are mainly designed for TD-SCDMA and TD-LTE of domestic operators, covering the frequency bands of F (1880-1920MHz), A (2010-2025MHz) and D (2575-2635MHz). At present, there is a large market demand for smart antennas in the frequency band around 3500MHz overseas, especially in the Middle East. The higher the frequency of the communication system, the higher the technical requirements for smart antenna products, and the more difficult it is to achieve related performance indicators. Summary of the invention

[0004] Therefore, in view of the above situation, the present invention proposes a TD-LTE smart antenna for use in the frequency band near 3500MHz, which includes a metal reflector, a radiation unit, a metal isolation wall, a metal isolation strip, and a feed network; the radiation unit, the metal isolation wall, and the metal isolation strip are fixedly installed on the front of the metal reflector, and the feed network is welded to the radiation unit and installed on the metal reflector.

[0005] Furthermore, the two sides of the metal reflector are bent in the opposite direction of the radiation surface to form an inverted U-shaped structure;

[0006] The feeding network is welded and connected to the radiation unit and installed on the front or back side of the metal reflection plate.

[0007] Furthermore, the radiation unit includes a radiation metal patch, a grounding plate, and a dipole feeding plate;

[0008] The radiating metal patch is suspended above the grounding plate, and the two are fixedly connected through the dipole feeding plate.

[0009] Further, the distance between the upper surface of the radiating metal patch and the lower surface of the ground plane is the overall height of the antenna radiating unit;

[0010] The overall height of the linear radiation unit is 1 / 8 wavelength of the working center frequency.

[0011] Furthermore, the two dipole feeding plates respectively feed the radiating metal patch by coupling, thereby forming two orthogonal ±45° polarized radiation combinations.

[0012] Furthermore, the TD-LTE smart antenna array is composed of an equal number of radiating units arranged along four parallel straight lines at equal intervals, with an interval of D1;

[0013] The D1 is 0.8 times the wavelength of 3800MHz;

[0014] The arrays are four antenna arrays, namely, a first array Array1, a second array Array2, a third array Array3, and a fourth array Array4.

[0015] Further, the horizontal spacing between the arrays is D2;

[0016] The D2 is 1 / 2 wavelength of the antenna working center frequency;

[0017] Accordingly, adjacent arrays are offset by a spacing of D1 / 2 along the array direction.

[0018] Furthermore, the metal isolation wall is divided into an L-shaped metal isolation wall and an inclined metal isolation wall, and the height is higher than the overall height of the radiation unit;

[0019] The L-shaped metal isolation walls are installed between adjacent arrays, and the number is three;

[0020] The inclined metal isolation walls are installed on both sides of the four-column antenna array, and the number is two;

[0021] The metal isolation strip is arranged between adjacent radiation units in the vertical direction, and the installation height is higher than the overall height of the radiation unit;

[0022] Furthermore, the feed network includes a phase shifter, a calibration circuit board, and a coaxial cable; the phase shifter is fixedly mounted on the back of the metal reflector, and the calibration circuit board is fixedly mounted on the front of the metal reflector. The radiation unit and the phase shifter, and the phase shifter and the calibration circuit board are all connected by welding with a coaxial cable.

[0023] Accordingly, the phase shifter is a passive device with one input and multiple outputs;

[0024] The calibration circuit board includes at least one equal power Wilkinson power divider and at least one microstrip directional coupler.

[0025] Furthermore, the operating frequency band of TD-LTE smart antenna is 3300-3800MHz.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] A TD-LTE smart antenna used in the frequency band near 3500MHz uses a low-stripped wide-band patch radiation unit with a height of only 1 / 8 of the wavelength of the working center frequency, which has the effect of reducing the antenna beam width. At the same time, a specific metal isolation piece is designed as the radiation boundary, so that the high-frequency band antenna can obtain a 65° wide unit beam with superior performance when the array arrangement of conventional low-frequency smart antennas is adopted. Based on this, relevant measures are adopted to strictly control the consistency of the amplitude and phase of each RF port, so that the high-frequency band smart antenna can obtain a synthetic beam with superior performance for business, broadcast, etc.

[0028] At present, the existing smart antenna products in the domestic market are mainly designed for TD-SCDMA and TD-LTE of domestic operators, covering frequency bands including F band (1880-1920MHz), A band (2010-2025MHz) and D band (2575-2635MHz). There is no smart antenna designed for the 3300-3800MHz frequency band. The present invention fills the relevant domestic gap.

[0029] The present invention proposes a TD-LTE smart antenna for use in a frequency band near 3500MHz, which has excellent performance and is the first of its kind in the country. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall front structure of the antenna of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the radiation unit of the present invention;

[0032] Figure 3 This is a schematic diagram of the overall back structure of the antenna of the present invention;

[0033] Figure 4 A schematic diagram illustrating the antenna structure of the present invention;

[0034] Description of reference numerals:

[0035] 1-metal reflector; 2-radiating unit; 3-metal isolation wall; 4-metal isolation strip; 5-phase shifter; 6-calibration circuit board; 7-coaxial cable; 8-feeding network; 201-radiating metal patch; 202-grounding plate; 203-diopter feeding plate; D-array spacing. DETAILED DESCRIPTION

[0036] In order to facilitate a better understanding of the purpose, structure, function, etc. of the present invention, the present invention is further described in conjunction with the accompanying drawings and specific implementation methods.

[0037] like Figure 1 , Figure 4 As shown, a TD-LTE smart antenna used in a frequency band near 3500MHz is characterized in that it includes a metal reflector 1, a radiation unit 2, a metal isolation wall 3, a metal isolation strip 4, and a feeding network 8; the radiation unit 2, the metal isolation wall 3, and the metal isolation strip 4 are fixedly installed on the front side of the metal reflector 1, and the feeding network 8 is respectively welded and connected to each radiation unit and installed on the front and back side of the metal reflector 1;

[0038] The two sides of the metal reflector 1 are bent in the opposite direction of the radiation surface to form an inverted U-shaped structure, which is used to suppress the backward radiation energy of the array antenna and improve the front-to-back ratio; at the same time, reinforcing rib structures are formed on both sides to strengthen the reflector and improve the overall structural performance of the antenna.

[0039] like Figure 2 As shown, the radiation unit 2 is a low-stripping broadband patch radiation unit of an existing patent, comprising a radiation metal patch 201, a ground plane 202, and a dipole feed plate 203 composed of a microstrip circuit. The radiation metal patch 201 is suspended above the ground plane 202, and the two are fixedly connected by the dipole feed plate 203. The upper surface of the radiation metal patch 201 and the lower surface of the ground plane 202 are the overall height of the antenna radiation unit, which is approximately 1 / 8 wavelength of the working center frequency. The two dipole feed plates 203 feed the radiation metal patch 201 respectively by coupling to form two orthogonal ±45° polarized radiation combinations.

[0040] The TD-LTE smart antenna array is arranged as follows: an equal number of radiating units 2 are arranged at equal intervals along four parallel straight lines, with a spacing D1 of 0.8 times the wavelength of 3800MHz, to form four antenna arrays, namely the first array Array1, the second array Array2, the third array Array3, and the fourth array Array4. Similar to conventional smart antennas, the horizontal spacing D2 between adjacent arrays is 1 / 2 wavelength of the antenna operating center frequency, and adjacent arrays are staggered by a spacing of D1 / 2 along the array direction.

[0041] The metal isolation wall 3 is divided into two types: an L-shaped metal isolation wall 3a and an inclined metal isolation wall 3b. Three L-shaped metal isolation walls 3a are installed between adjacent arrays, and two inclined metal isolation walls 3b are installed on both sides of the four-column antenna array, and their heights are higher than the overall height of the radiation unit 2. The metal isolation strip 4 is arranged between adjacent radiation units in the vertical direction, and its installation height is higher than the overall height of the radiation unit 2. The above arrangement can improve the co-polarization and hetero-polarization isolation of the smart antenna, as well as the cross-polarization discrimination rate of the radiation performance, sector power ratio and other indicators.

[0042] The height of radiation unit 2 is 1 / 8 wavelength of the working center frequency, which is only half of the commonly used half-wave dipole. It is a patch radiation unit with reduced array antenna beam width. The selection of radiation unit 2 and the design of specific radiation boundaries enable the smart antenna to obtain the required unit beam with excellent performance and 65° horizontal beam width under the above array arrangement; and the unit beam performance is an important basis for the performance of synthetic beams such as service beams and broadcast beams.

[0043] like Figure 3 , Figure 4 As shown, the feeding network 8 includes a phase shifter 5, a calibration circuit board 6 and a coaxial cable 7. The phase shifter 5 is a passive device with one input and multiple outputs. The one phase shifter 5 actually has two phase shifting systems. The output ports of the four phase shifters PS1, PS2, PS3 and PS4 are respectively connected to the radiation units in the first array Array1, the second array Array2, the third array Array3 and the fourth array Array4 by welding through the coaxial cable 7. The eight total input ports of the four phase shifters are also connected to the calibration circuit board 6 by welding through the coaxial cable 7, forming radio frequency ports such as Port1, Port5, Port2, Port6, Port3, Port7, Port4 and Port8 respectively.

[0044] The calibration circuit board 6 includes a plurality of equal-power Wilkinson power dividers and a plurality of microstrip directional couplers, and the calibration port PortC derived therefrom calibrates the amplitude and phase of each radio frequency port to keep them consistent.

[0045] Preferably, compared with conventional low-frequency smart antennas, the calibration circuit board 6 uses isolation resistors and grounding resistors with higher precision to improve the amplitude and phase consistency indicators of the entire antenna.

[0046] Preferably, the eight microstrip directional couplers in the calibration circuit board 6 are provided with corresponding debugging branches for debugging the amplitude and phase consistency indicators of all radio frequency ports of the smart antenna.

[0047] Preferably, the eight N-type RF ports of the antenna are connected to the calibration circuit board 6 via coaxial cables 7. The eight sections of coaxial cables need to be strictly tested by instruments to keep the electrical length consistent, so as to ensure the amplitude and phase consistency indicators of all RF ports of the antenna.

[0048] Preferably, the operating frequency band of the TD-LTE smart antenna proposed in the present invention is 3300-3800 MHz.

[0049] A TD-LTE smart antenna used in the frequency band near 3500MHz uses a low-stripped wide-band patch radiation unit with a height of only 1 / 8 of the wavelength of the working center frequency, which has the effect of reducing the antenna beam width. At the same time, a specific metal isolation piece is designed as the radiation boundary, so that the high-frequency band antenna can obtain a unit beam with a horizontal beam width of 65° with superior performance when the array arrangement of conventional low-frequency smart antennas is adopted. Based on this, relevant measures are adopted to strictly control the consistency of the amplitude and phase of each RF port, so that the high-frequency band smart antenna can obtain a synthetic beam with superior performance for business, broadcast, etc.

[0050] At present, the existing smart antenna products in the domestic market are mainly designed for TD-SCDMA and TD-LTE of domestic operators, covering frequency bands including F band (1880-1920MHz), A band (2010-2025MHz) and D band (2575-2635MHz). There is no smart antenna designed for the 3300-3800MHz frequency band. The present invention fills the relevant domestic gap.

[0051] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A TD-LTE smart antenna for use in a frequency band near 3500MHz, characterized in that: The antenna array is composed of the following structural units: a metal reflector, a radiation unit, a metal isolation wall, a metal isolation strip, and a feed network; the radiation unit, the metal isolation wall, and the metal isolation strip are fixedly mounted on the metal reflector, and the feed network is welded and connected to the radiation unit and mounted on the metal reflector; The two sides of the metal reflector are bent in the opposite direction of the radiation surface to form an inverted U-shaped structure; the inverted U-shaped structure is used to suppress the backward radiation energy of the array antenna and improve the front-to-back ratio; the two sides form a reinforcing rib structure; the feeding network is welded and connected to the radiation unit and installed on the front or back of the metal reflector; the radiation unit includes a radiation metal patch, a grounding plate, and a dipole feeding plate; The radiating metal patch is suspended above the grounding plate, and the two are fixedly connected through the dipole feeding plate; The two dipole feeding plates feed the radiating metal patch respectively by coupling, forming two orthogonal ±45° polarized radiation combinations; The antenna array comprises an equal number of radiating units arranged at equal intervals along four parallel straight lines, the spacing between the radiating units is D1; ​​the D1 is 0.8 times the wavelength of 3800MHz; the array is a four-column antenna array consisting of a first array Array1, a second array Array2, a third array Array3, and a fourth array Array4; the horizontal spacing between the arrays is D2; the D2 is 1 / 2 wavelength of the antenna working center frequency; accordingly, adjacent arrays are staggered by a spacing of D1 / 2 along the array extension direction; The distance between the upper surface of the radiating metal patch and the lower surface of the ground plane is the overall height of the antenna radiating unit; the overall height of the radiating unit is 1 / 8 wavelength of the working center frequency; it is half of the commonly used half-wave dipole, and is a low-stripping wide-band patch radiating unit with reduced array antenna beam width; The metal isolation wall is divided into an L-shaped metal isolation wall and an inclined metal isolation wall, and the height of both is higher than the overall height of the radiation unit; the L-shaped metal isolation wall is installed between adjacent arrays, and the number is three; the inclined metal isolation wall is installed on both sides of the four-column antenna array, and the number is two; the metal isolation strip is arranged between adjacent radiation units in the extension direction of the array, and the installation height is higher than the overall height of the radiation unit. The above arrangement improves the co-polarization and hetero-polarization isolation of the smart antenna, as well as the cross-polarization identification rate and sector power ratio of the radiation performance; The selection of radiation units and the design of specific radiation boundaries enable the smart antenna to obtain the required unit beam with a horizontal beam width of 65° with excellent performance in the above array arrangement; The feeding network includes a phase shifter, a calibration circuit board, and a coaxial cable; The phase shifter is fixedly installed on the back of the metal reflector, the calibration circuit board is fixedly installed on the front of the metal reflector, and the radiation unit and the phase shifter, as well as the phase shifter and the calibration circuit board are all connected by coaxial cable welding; Correspondingly, the phase shifter is a passive device with one input and multiple outputs; the calibration circuit board includes at least one equal power Wilkinson power divider and at least one microstrip directional coupler; the operating frequency band of the TD-LTE smart antenna is 3300-3800MHz.

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