CN109067439B - Testing method adopted by digital multi-beam array transmitting device - Google Patents
Testing method adopted by digital multi-beam array transmitting device Download PDFInfo
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- CN109067439B CN109067439B CN201811084553.4A CN201811084553A CN109067439B CN 109067439 B CN109067439 B CN 109067439B CN 201811084553 A CN201811084553 A CN 201811084553A CN 109067439 B CN109067439 B CN 109067439B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0408—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more beams, i.e. beam diversity
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/10—Monitoring; Testing of transmitters
- H04B17/11—Monitoring; Testing of transmitters for calibration
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/10—Monitoring; Testing of transmitters
- H04B17/11—Monitoring; Testing of transmitters for calibration
- H04B17/12—Monitoring; Testing of transmitters for calibration of transmit antennas, e.g. of the amplitude or phase
Abstract
The invention discloses a digital multi-beam-array transmitting device which comprises a multi-path direct digital frequency synthesizer module, a multi-path millimeter wave transmitting front-end module and an antenna radiation unit. The invention also discloses a test method adopted by the digital multi-beam array transmitting device. The traditional phased array can only generate one wave beam at the same time, but the whole transmitting device related to the invention can simultaneously generate a plurality of independently controllable wave beams within +/-40 degrees to cover a specific area, and the pointing direction of the wave beams does not need to be switched according to the time like the traditional phased array. Meanwhile, each wave beam generated by the invention utilizes all antenna apertures, and the gain of each wave beam is basically consistent with the gain of a corresponding directional wave beam generated by the phased array alone. The invention is an excellent choice for millimeter wave communication.
Description
Technical Field
The invention relates to the field of microwave and millimeter waves, in particular to a digital multi-beam array transmitting device and a testing method adopted by the same.
Background
Due to the advantages of large bandwidth and high data transmission rate, the millimeter wave technology has become a hot research point of communication technology in recent years. In order to improve the signal to noise ratio, reduce the doppler effect, and improve data security, a high-gain antenna beam needs to be used. The higher the antenna gain, the narrower the beam range covered. Conventional phased array antennas can only produce one beam at a time, and if multiple users at different angular positions are to be covered, the pointing direction of the beam needs to be switched at different times. In order to cover users at different angular positions simultaneously, it is necessary to generate multiple antenna beams simultaneously, which can be steered independently and flexibly. There are two common transmit multi-beam antenna schemes, the first of which uses multiple independent sets of multi-channel phased array transmitter systems, each set transmitting a beam. The second solution is to use a passive method to implement multiple beams, for example, a beam forming network such as butler matrix to feed the array antenna.
The first scheme has the disadvantages that the traditional phased array system can only generate one wave beam at the same time, and if a plurality of wave beams are generated simultaneously, a plurality of phased array systems are needed, so that the number of radio frequency channels is increased invisibly, and the cost of the whole system is increased. Also, the antenna apertures connected by these systems cannot be shared. For example, a system has 15 antenna elements, and 30 antenna elements are required to generate two beams, which are divided into two groups connected to respective system channels. This adds virtually to the size of the antenna array, but the resulting beams do not utilize all of the antenna apertures, using only half the number of antenna apertures per beam. And in the second scheme, the passive Butler matrix is used for simultaneously generating multiple beams, and the multiple beams can simultaneously share the caliber of the whole antenna. However, if the number of antenna elements is too large, the butler matrix of a high order is difficult to design and insertion loss is large. This means that if the number of beams to be generated is large, the energy lost in the beam forming network may even exceed the gain of the array factor, and therefore, it is not suitable for large-scale butler matrix design. Meanwhile, another disadvantage of passive multi-beam is that once the beam forming network design is completed, the beam direction cannot be changed, and the flexibility of the system as a whole is poor.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a digital multi-beam array transmitting device which can simultaneously generate a plurality of beams without increasing the number of radio frequency channels and introducing extra beam forming network loss and can simultaneously utilize all the calibers of radiation units for each beam and a test method adopted by the device.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the following technical scheme:
the invention relates to a digital multi-beam array transmitting device, which comprises a multi-path direct digital frequency synthesizer module, a multi-path millimeter wave transmitting front-end module and an antenna radiation unit; each direct digital frequency synthesizer module comprises a DDS, the DDS outputs signals to a first sound surface filter, the first sound surface filter outputs signals to a first driving amplifier, the first driving amplifier outputs signals to a second sound surface filter, the second sound surface filter outputs signals to a second driving amplifier, and the second driving amplifier outputs intermediate frequency signals through a radio frequency switch; the direct digital frequency synthesizer module corresponds to the millimeter wave transmitting front end module one by one, and an intermediate frequency signal output by the direct digital frequency synthesizer module is sent to the millimeter wave transmitting front end module; and the signal output by the millimeter wave transmitting front end module is radiated out through the antenna radiation unit.
Furthermore, each path of millimeter wave transmitting front-end module comprises a frequency mixer, an intermediate frequency signal output by the direct digital frequency synthesizer module is sent to one input end of the frequency mixer, a local oscillation signal is sent to the other input end of the frequency mixer, the frequency mixer outputs a signal to the band-pass filter, the band-pass filter outputs a signal to the driving amplifier, and the driving amplifier outputs a signal to the antenna radiation unit.
Further, the antenna radiation unit is a double-gradient slot antenna unit.
Furthermore, the double-gradient slot antenna unit is designed and manufactured by adopting a microwave plate Taconnic TLY-5 with the dielectric constant of 0.254mm being 2.2.
The testing method adopted by the digital multi-beam array transmitting device comprises the following steps:
s1: debugging a multipath direct digital frequency synthesizer module and a multipath millimeter wave transmitting front-end module, and designing structural parameters of an antenna radiation unit;
s2: calibrating the whole multi-beam transmitting device in a darkroom;
s3: synthesizing the power and the phase of signals to be transmitted by each path of millimeter wave transmission front end module according to the number and the direction of beams to be generated, wherein the synthesis process is completed in a direct digital frequency synthesizer module;
s4: and loading the power and the phase of the signal which is obtained by integrating the direct digital frequency synthesizer modules in the step S3 and is to be transmitted by each path of millimeter wave transmission front end module into the corresponding millimeter wave transmission front end module.
Has the advantages that: the invention discloses a digital multi-beam array transmitting device and a testing method adopted by the same. The amplitude phase of each path can be independently adjusted by utilizing a direct digital frequency synthesizer (DDS), so that the generation of a plurality of beams at the same time can be flexibly realized. Compared with the first scheme, the scheme provided by the invention greatly reduces the number of radio frequency channels, and each beam uses the aperture of the full antenna array. Compared with the second scheme, a Butler matrix beam forming network is not needed, the extra insertion loss caused by the beam forming network is avoided, and the millimeter wave energy is saved. And the pointing direction of the generated beams can be flexibly and independently adjusted. In addition, each beam generated by the invention utilizes all antenna apertures, and the gain of each beam is basically consistent with the gain of a corresponding directional beam generated by the phased array alone.
Drawings
FIG. 1 is a schematic diagram of a multi-channel millimeter wave front end and multi-beam generation according to the present invention;
FIG. 2 is a block diagram of a multi-way direct digital frequency synthesizer according to the present invention;
FIG. 3 is a beam scanning diagram under the condition of traditional phased array single beam (-40- +40 degrees, with 10 degrees interval);
FIG. 4 is a schematic diagram of the simultaneous generation of two beam patterns pointing at-10 degrees and +20 degrees, respectively;
FIG. 5 is a schematic diagram of the simultaneous generation of three beam patterns pointing at-20 degrees, -5 degrees, +20 degrees, respectively;
fig. 6 shows beam patterns of-20, -14, -8, -2, +4, +10, +16, +22 for simultaneously generating 8 orthogonal beams.
Detailed Description
The technical solution of the present invention will be further described with reference to the following embodiments.
The specific embodiment discloses a digital multi-beam-array transmitting device which comprises a multi-path direct digital frequency synthesizer module, a multi-path millimeter wave transmitting front-end module and an antenna radiation unit.
As shown in fig. 2, each of the direct digital frequency synthesizer modules includes DDS5, DDS5 outputs a signal to first saw filter 6, first saw filter 6 outputs a signal to first driver amplifier 7, first driver amplifier 7 outputs a signal to second saw filter 8, second saw filter 8 outputs a signal to second driver amplifier 9, and second driver amplifier 9 outputs an intermediate frequency signal through rf switch 10. The direct digital frequency synthesizer module corresponds to the millimeter wave transmitting front end module one by one, and one path of intermediate frequency signals output by the direct digital frequency synthesizer module are sent to one path of millimeter wave transmitting front end module. And the signal output by the millimeter wave transmitting front end module is radiated out through the antenna radiation unit.
As shown in fig. 1, each millimeter wave transmitting front end module includes a mixer 1, an intermediate frequency signal output by the direct digital frequency synthesizer module is sent to one input end of the mixer 1, a local oscillator signal is sent to the other input end of the mixer 1, the mixer 1 outputs a signal to a band-pass filter 2, the band-pass filter 2 outputs a signal to a driving amplifier 3, and the driving amplifier 3 outputs a signal to an antenna radiation unit. And 15 paths of millimeter wave transmitting front-end modules are calculated in total.
The antenna radiation unit is a double-gradient slot antenna unit and is designed and manufactured by adopting a microwave plate Taconnic TLY-5 with the dielectric constant of 0.254mm being 2.2.
The specific embodiment also discloses a test method adopted by the digital multi-beam-array transmitting device, which comprises the following steps:
s1: and debugging the multipath direct digital frequency synthesizer module and the multipath millimeter wave transmitting front-end module, and designing the structural parameters of the antenna radiation unit to ensure that the reflection coefficient of the antenna radiation unit meets the requirements of the system.
S2: the whole multi-beam emitting device is calibrated in a darkroom.
S2.1: and taking the first channel as a reference, opening the second channel, and closing all the rest channels. The amplitude and phase of the second channel are adjusted so that the total energy radiated by the first and second channels is minimized. At this time, after the phase of the second channel is reversed, the first channel and the second channel are in the same phase, and the second channel is calibrated.
S2.2: and keeping the first channel normally open, closing the second channel and opening the third channel to finish the operation of the step S2.1. And repeating the above steps for all the rest channels, and completing the calibration of the system for all the millimeter wave channels after the calibration is completed.
S3: the power and the phase of signals which are to be transmitted by each path of millimeter wave transmission front end module are synthesized according to the number and the direction of beams to be generated, and the synthesis process is completed in a direct digital frequency synthesizer module. For example, to generate N beams, the directions are respectively theta1,θ2,…,θNThe amplitude and phase applied to each channel by the k (k ═ 1, 2.., N) th beam is:
the different amplitudes and phases corresponding to the different beams generated by each channel are vector-summed, i.e., the relative amplitudes and phases of the transmissions required by the channel to generate the multi-beam pattern. Here both amplitude and phase are normalized to the amplitude, phase of channel 1. Amplitude B required for the i (i ═ 1, 2., M) th channel to produce N beams simultaneouslyiAnd phase ΨiThe following were used:
the synthesized far-field pattern formula is as follows:
wherein, Eli(i 1, 2., M) is the active pattern of the ith twinax slot antenna element, and F is the overall multi-beam transmitting pattern.
S4: and (4) loading the power and the phase of the signal which is obtained by directly synthesizing the digital frequency synthesizer module in the step (S3) and is to be transmitted by each path of millimeter wave transmission front end module into the corresponding millimeter wave transmission front end module, namely, controlling the turntable to measure the far field directional diagram which simultaneously generates a plurality of beams by using the frequency spectrograph.
In order to verify the correctness and effectiveness of the multi-beam generation method provided by the invention, only one beam is generated and different angles are scanned. As shown in fig. 3, the resulting single beam scan is plotted together to see that in the single beam scan case the beam can be scanned over a range of plus or minus 40 degrees with the 3dB width of the beam around 0 degrees being around 6 degrees. The zero level in fig. 3 is normalized with the maximum level value of the beam of 0 degrees.
Next, several sets of experiments were designed and performed to generate multiple beams simultaneously, and the simultaneous multi-beam patterns of the antenna array were tested in a dark room, all at 24.3 GHz. Fig. 4 shows the simultaneous generation of two beam patterns pointing at-10 degrees and +20 degrees, respectively, and fig. 5 shows the simultaneous generation of three beam patterns pointing at-20, -5, +20 degrees, respectively. From fig. 4 and 5, it can be seen that the directional pattern pointing fits well with theoretical predictions, and that the resulting multiple beams have 3dB widths, similar to the single beam case, all around 6 degrees. This shows that each beam generated simultaneously utilizes all antenna apertures and that the gain of each beam is substantially identical to the gain of a corresponding pointing beam generated individually. It should be noted that the zero level of the directional diagrams in fig. 4-6 is normalized by the maximum level value of the 0 degree beam in fig. 3 when the total transmission power is consistent.
When the whole transmitting machine generates a plurality of beams simultaneously, the total transmitted power is necessarily changed from one direction to a plurality of directions, so that the transmitted power divided by each beam is reduced. Each beam gain is approximately constant, and the beamwidth of the directional diagram is approximately constant, and the equivalent omnidirectional radiation power [ eirp (dBm) ═ transmission power (dBm) + gain (dB) ] is reduced according to the reduction of the transmission power divided by the beam. As can be seen in fig. 4-6: when two beams are simultaneously generated under the condition that the total transmission power is consistent, the total transmission power is divided into two, and the Equivalent Isotropic Radiated Power (EIRP) of each beam is reduced by 3 dB. When three beams are generated simultaneously, the total transmission power is divided into three, and the Equivalent Isotropic Radiated Power (EIRP) of each beam is reduced by 4.5 dB. When eight beams are generated simultaneously, the total transmission power is divided into eight, and the Equivalent Isotropic Radiated Power (EIRP) is obtained.
Claims (4)
1. A test method adopted by a digital multi-beam array transmitting device is characterized in that: the device comprises a multi-path direct digital frequency synthesizer module, a multi-path millimeter wave transmitting front-end module and an antenna radiation unit; each direct digital frequency synthesizer module comprises a DDS, the DDS outputs signals to a first sound surface filter, the first sound surface filter outputs signals to a first driving amplifier, the first driving amplifier outputs signals to a second sound surface filter, the second sound surface filter outputs signals to a second driving amplifier, and the second driving amplifier outputs intermediate frequency signals through a radio frequency switch; the direct digital frequency synthesizer module corresponds to the millimeter wave transmitting front end module one by one, and an intermediate frequency signal output by the direct digital frequency synthesizer module is sent to the millimeter wave transmitting front end module; the signal output by the millimeter wave transmitting front end module is radiated out through the antenna radiation unit;
the testing method adopted by the digital multi-beam array transmitting device comprises the following steps:
s1: debugging a multipath direct digital frequency synthesizer module and a multipath millimeter wave transmitting front-end module, and designing structural parameters of an antenna radiation unit;
s2: calibrating the whole multi-beam transmitting device in a darkroom;
s3: synthesizing the power and the phase of signals to be transmitted by each path of millimeter wave transmission front end module according to the number and the direction of beams to be generated, wherein the synthesis process is completed in a direct digital frequency synthesizer module; generating N beams, each directed at a phase θ1,θ2,…,θNThe corresponding direction, k 1,2, N, the k-th beam is applied at the amplitude a corresponding to each channelkiAnd phase
Comprises the following steps:
wherein, i is 1,2, and M is the number of channels, and different amplitude phases corresponding to different beams generated by each channel are vector-superposed, that is, the relative amplitude and phase of the transmission required by the channel to generate a multi-beam pattern; here, the amplitude and the phase are normalized by the amplitude and the phase of the channel 1; amplitude B required by ith channel to simultaneously generate N beamsiAnd phase ΨiThe following were used:
the synthesized far-field pattern formula is as follows:
wherein, EliThe antenna unit is an active directional diagram of the ith double gradient slot antenna unit, and F is a directional diagram of integrally transmitting multi-beam;
s4: and loading the power and the phase of the signal which is obtained by integrating the direct digital frequency synthesizer modules in the step S3 and is to be transmitted by each path of millimeter wave transmission front end module into the corresponding millimeter wave transmission front end module.
2. The method of testing employed by a digital multi-beam-array transmitting device according to claim 1, characterized by: each path of millimeter wave transmitting front end module comprises a frequency mixer, an intermediate frequency signal output by the direct digital frequency synthesizer module is sent to one input end of the frequency mixer, a local oscillator signal is sent to the other input end of the frequency mixer, the frequency mixer outputs a signal to the band-pass filter, the band-pass filter outputs a signal to the driving amplifier, and the driving amplifier outputs a signal to the antenna radiation unit.
3. The method of testing employed by a digital multi-beam-array transmitting device according to claim 1, characterized by: the antenna radiation unit is a double-gradient slot antenna unit.
4. A method of testing employed by a digital multi-beam array transmitter of claim 3, characterized by: the double-gradient slot antenna unit is designed and manufactured by adopting a microwave plate Taconnic TLY-5 with the dielectric constant of 0.254mm being 2.2.
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| CN110798236A (en) * | 2019-11-12 | 2020-02-14 | 天津津航计算技术研究所 | Multi-beam space power synthesis radio frequency front-end circuit |
| CN111541471B (en) * | 2020-04-21 | 2021-04-02 | 中国电子科技集团公司第五十四研究所 | Digital multi-beam phased-array antenna device for ad hoc network communication |
| CN111525967B (en) * | 2020-05-11 | 2022-04-22 | 南京华络通信技术有限公司 | Millimeter wave terminal test system and method |
| CN113054991B (en) * | 2021-02-02 | 2022-12-20 | 中国电子科技集团公司第二十九研究所 | Implementation method of switch matrix, module and beam forming network |
| CN113193889B (en) * | 2021-06-16 | 2022-08-19 | 嘉兴军创电子科技有限公司 | Ultra-wideband digital multi-beam transmitting method based on fractional time delay |
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