Millimeter wave integration multichannel active transmitting antenna and phase compensating method thereof
Technical field
The invention belongs to the active antenna technical field.
Background technology
Active transmitting antenna directly is connected active transmitter module and forms with antenna element, has advantages such as volume is little, in light weight, compact conformation, has a wide range of applications in fields such as mobile communication, military detection, electronic countermeasuress.In recent years, along with the fast development of monolithic integrated microwave circuit (MMIC), spatial power synthetic technology and millimeter wave whole plane integrated technology, promoted millimeter wave active transmitting antenna technological direction maturation, the millimeter wave active transmitting antenna more becomes the focus of research.But independently active transmitting antenna can't realize that wave beam forms and the wave beam electric scanning, and therefore multichannel active transmitting antenna has more deep learning value and construction value.
For active transmitting antenna, interchannel phase error will determine the accuracy that its space combined coefficient and launching beam form.Along with the development of microelectronic technique, in order to realize the miniaturization purpose, active device all is to adopt the MMIC technology to realize.Based on existing home and abroad manufacture level, the chip-scale active device is easy to realize the consistency of amplitude output signal, but phase equalization can't guarantee that and phase error is within ± 180 degree scopes.Common active transmitting antenna all adopts the method for adding millimeter phase-shifter to carry out phase compensation, and its Insertion Loss is bigger, reaches 7dB; And the phase modulation low precision, the minimum angle adjustable of phase place is 11.25 degree; Increase a phase shifter and also can increase by 10 mm lengths, system bulk is increased.For integrated multichannel millimeter wave active transmitting antenna, guaranteeing under the constant condition of power output, under interchannel range error 0.5dB retrains with interior system requirements with interior and phase error 10 degree, the method of adding millimeter phase-shifter is in the past carried out the method for phase compensation and miniaturized system structure and index request the contradiction that can't be in harmonious proportion is taken place, and still do not have relevant effective implementation method at home and abroad, therefore how easy compensate for emission passage amplitude phase error is the crucial difficult point that realizes millimeter wave integration multichannel active transmitting antenna in the high integration active circuit.
In order to realize the integrated and miniaturization Design of millimeter wave active transmitting antenna, based on existing integrated horizontal, transmitter module all adopts the multichip modules technology based on the MMIC technology, and the transmission channel of being made up of the casacade multi-amplifier cascade in this kind implementation is than the consistency that is easier to guarantee the amplitude of transmitting, and phase equalization is difficult to realize, being subject to integrated, miniaturization Design simultaneously requires to increase phase shifter, therefore the phase error that transmits is bigger, is applied to active transmitting antenna and can has a strong impact on the active antenna transmitting pattern.
Summary of the invention
Main purpose of the present invention is to solve above technical problem.Especially, an object of the present invention is to provide a kind of antenna assembly, it can realize millimeter wave integration multichannel active transmitting antenna in the mode of Highgrade integration, and compares with relevant traditional product and not need to use millimeter phase-shifter.
Another object of the present invention provides a kind of simple and easy implementation method of active transmitting antenna interchannel phase equalization, is a kind of passive implementation method, and does not need to increase antenna volume.
In order to realize above purpose, aspect of invention, the invention provides a kind of millimeter wave integration multichannel active transmitting antenna device, comprise millimeter wave array antenna, multi-channel active transmitter module.Millimeter wave array antenna and multi-channel active transmitter module adopt seamless draw bail, and the multi-channel active transmitter module has the phase compensating network that is made of medium loaded microstrip line.
The millimeter wave integration multichannel active transmitting antenna device, it comprises: millimeter wave array antenna, multi-channel active transmitter module.The millimeter wave array antenna is the planar array antenna that is beneficial to miniaturization, can adopt micro-strip array antenna, Waveguide slot array antenna.The multi-channel active transmitter module includes source amplifier, microstrip line, phase compensating network, merit parallel circuit and metal case, and each assembly in the module is the millimeter wave whole plane integrated circuit based on MMIC (millimeter wave monolithic integrated circuit) technology.Millimeter wave array antenna and multi-channel active transmitter module adopt seamless draw bail, save the connection feeder line, realize the integration multichannel active transmitting antenna structure.Wherein, the activated amplifier of multi-channel active transmitter module comprises final power amplifier (PA) and promotes level driving amplifier (A), activated amplifier is realized by high performance mmic chip, promote the level amplifier and determine, enough also can not promote a grade amplifier if promote power according to the performance number that the final power amplifier needs promote; Microstrip line (MS), each function element of cascade utilizes the gold thread bonding to realize connecting of function element and microstrip line (MS); Phase compensating network (PC), loaded medium is arranged in metal case inside and the air shielding cavity above microstrip line and realizes channel phases error compensation, and loaded medium arrives on the input stage microstrip line before of final power amplifier (PA) after being arranged on transmitter module merit parallel circuit (Dv1 and Dv2) output stage; Multistage power splitter (Dv1 and Dv2), realization is multiplexing to the millimeter-wave signal source module, guarantees the antenna miniaturization characteristics to reduce mmic chip quantity.That this antenna assembly provided by the invention possesses is integrated, miniaturization, easy characteristics such as realization, and can be applied to the broadband millimeter-wave radar.
Loaded medium in the phase compensating network is the high dielectric constant of the little and dielectric constant of the loss angle of millimeter wave frequency band greater than air, and loaded medium commonly used is polytetrafluoroethylene, ceramic powders or pottery.Loaded medium can be an arbitrary shape, all can cause phase compensation as long as put in position.And be the predictability that guarantees phase compensation amount, the rectangular shape of selective rule is loaded as the best.Under the situation of known phase error theta, can derive the computing formula of regular cuboid medium length under the no changeover portion situation, for
At the transition network of loading stepped shape in medium both sides or ramped shaped, transition network length is changeable as required.By formula (1) as can be seen, under the condition that microstrip line length allows, the interchannel phase compensation scope of utilizing implementation method provided by the invention to realize is the 0-360 degree.
According to another aspect of the present invention, a kind of phase error compensation method of millimeter wave integration multichannel active transmitting antenna device is provided, it comprises: the millimeter wave array antenna that will make in advance connects with the multichannel active transmitting antenna module is seamless; Measure multichannel active transmitting antenna and obtain the channel phases error; In the multi-channel active transmitter module, loaded medium is set, to constitute phase compensating network.
Material, length, thickness, the width of phase compensation amount and loaded medium and the position of putting are relevant, but realize that the principle of phase compensation is consistent.
The material of its loaded medium just can be realized effective active transmitting antenna phase compensation function so long as different with the dielectric constant of air and less in the loss angle of millimeter wave frequency band.Loaded medium can adopt polytetrafluoroethylene, ceramic powders or pottery, and its dielectric constant is respectively 2.2,3.48,9.8.
The compensation method that the present invention proposes, the multi-channel active transmitter module includes source amplifier, microstrip line, phase compensating network, merit parallel circuit and metal case, and described loaded medium is arranged in the air shielding cavity of metal case inside and microstrip line (MS) top.It is less that the phase compensating network (PC) that the present invention proposes inserts loss, in order to guarantee that phase compensating network (PC) does not influence power output, arrive on input stage any microstrip line before of final power amplifier (PA) after being placed on transmitter module merit parallel circuit (Dv2) output stage, the input of final power amplifier (PA) promotes power need reserve the 0.5dB margin of power, make final power amplifier work in the saturation region, the amplitude consistency that guarantees to transmit does not change always.
In principle, but because the existence of electric field, loaded medium is placed in optional position, conductor belt top all can produce phase-shift characterisitc, so the position that medium is put not is unique, but the principle of phase compensation all is consistent, just compensation rate is different, with medium be placed in conductor belt directly over the phase-shift phase maximum that causes.Best putting position be the microstrip line conductor belt directly over, and the medium both sides closely link to each other with the shielding cavity sidewall, it is fully contacted with metallic shield box sidewall, this moment, the heat of medium inside can conduct by sidewall to greatest extent, had improved the power capacity of phase compensating network and temperature stability to guarantee the power capacity of this phase compensating network.
Loaded medium can be an arbitrary shape, all can cause phase compensation as long as put in position.And be the predictability that guarantees phase compensation amount, the rectangular shape of selective rule is loaded as the best.Under the situation of known phase error theta, can derive the computing formula of regular cuboid medium length b under the no changeover portion situation, for
Wherein, b is the length of phase compensation section, and θ is the known phase error, λ
0Be the microstrip line guide wavelength of air dielectric, ε
ReEquivalent relative dielectric constant for propagation medium.
In order to reduce because loaded medium produces the deterioration to the Insertion Loss and the standing wave of system of compensating network that discontinuity surface causes, at the transition network of loading stepped shape in medium both sides or ramped shaped.Transition network length is changeable as required, also can not have.This transition network length is long more, and transition effect is good more, therefore under the condition that microstrip line length allows, increases the length a of gradual transition section as far as possible; If the microstrip line length limited can only be that cost guarantees the phase compensation performance to sacrifice standing wave and Insertion Loss, promptly reduces a, opposite extreme situations is the rectangle loaded medium that does not have changeover portion.
By formula (1) as can be seen, under the condition that microstrip line length allows, the interchannel phase compensation scope of utilizing implementation method provided by the invention to realize is the 0-360 degree.
High dielectric constant replaces air, has increased the effective dielectric constant ε of microstrip line transmission medium
Re, cause the guide wavelength λ of transmission line
gReduce, thereby cause phase-shift phase to change.Implementation method provided by the invention can be applied to all frequency ranges, and according to different operating frequencies, the phase compensation value of identical loaded medium length correspondence changes to some extent, and its value is
Wherein, θ is the known phase error, and b is the length of phase compensation section, λ
0Be the microstrip line guide wavelength of air dielectric, ε
ReEquivalent relative dielectric constant for propagation medium.
The beneficial effect of antenna assembly provided by the invention and implementation method is:
1) active transmitting antenna utilizes the space composition principle to obtain big transmitting power, saves circuit stages power comprise network, can improve the synthetic efficient of power greatly.For microstrip antenna, can farthest reduce the loss of feeding network, improve the effective radiation gain of antenna significantly.
2) utilize the microstrip line that plays each function element effect of connection in the active transmitter module, choose the full phase error compensation that suitable high dielectric constant realizes that ± 180 degree scopes are interior, need not to increase the active antenna volume like this to add the phase error compensation network, satisfy system's miniaturization requirement.
3) phase compensation section places before the final power amplifier input stage, and promotion power is reserved certain allowance and can be guaranteed that just transmission channel all is in the saturation region all the time, so the adjustment method of this millimeter wave active transmitting antenna does not influence transmitting power and transmitting pattern.
4) bandwidth of operation of the Ka wave band active transmitting antenna of this adjustment method of process can satisfy the application requirements of mobile communication, military detection and electronic countermeasures substantially greater than 500MHz.
5) phase compensating method is simple and easy to operate, utilize the microstrip line that plays the cascade effect in the transmission channel between each device to finish, loaded medium can adopt polytetrafluoroethylene, pottery or the like, and directly gets final product by gluing the connecing of low-loss between loaded medium and the microstrip line.
6) the active transmitting antenna adjustment method of the present invention's proposition also can be applied to other all frequency ranges, just according to different operating frequencies, the phase compensation value of identical loaded medium length correspondence changes to some extent, and concrete loaded medium length calculation formula is seen formula (2).
Description of drawings
Fig. 1-integrated millimeter wave active antenna transmission channel theory diagram, wherein: PA-final power amplifier, A-promote level amplifier, Dv-power splitter;
Fig. 2---the phase compensating method schematic diagram of medium loaded microstrip line, wherein: 1-loaded medium, 2-microstrip line, 3-metallic shield box;
Fig. 3---load the phase shift measured result that different high dielectric constants cause;
Fig. 4---the transmission channel phase error measured result before and after the compensation,
Wherein: Fig. 4-1---measured result before and after the 95 degree phase error compensations, Fig. 4-2-50 spends phase place, measured result before and after the error compensation, Fig. 4-3---measured result before and after the 35 degree phase error compensations;
The pitching of Fig. 5---four-way millimeter wave active antenna and orientation transmitting pattern measured result,
Wherein: Fig. 5-1---azimuth pattern, Fig. 5-2---pitch orientation figure;
Fig. 6-active transmitting antenna closed loop compensation method flow diagram.
Embodiment
The invention will be further described below in conjunction with drawings and Examples.
Fig. 1 is an integrated millimeter wave active antenna transmission channel theory diagram, is example with four the tunnel.For realizing miniaturization structure, four transmission channels realize that by two-stage merit parallel circuit function element is few like this, compact conformation in radio frequency part; Shortcoming is that the interchannel phase error compensation must be finished in radio frequency part, and the method for adding millimeter phase-shifter is in the past carried out the method inefficacy of phase compensation.
Fig. 2 is the phase compensating method schematic diagram of medium loaded microstrip line.Load high dielectric constant in the air shielding cavity above microstrip line.In order to guarantee that phase compensating network does not influence power output, before the input stage of final power amplifier, realize the phase error compensation of multichannel transmission channel by the easy phase compensating network of loaded medium on the microstrip line, thereby realize integrated millimeter wave multichannel active transmitting antenna.Can change the compensating phase shift amount by length and the material (being dielectric constant) that changes loaded medium.
Fig. 3 loads the phase shift measured result that different high dielectric constants cause.Three kinds of filled medias are respectively polytetrafluoroethylene, ceramic powders and pottery, its dielectric constant is respectively 2.2,3.48 and 9.8, wherein polytetrafluoroethylmaterial material thickness is 3 millimeters, and the thickness of ceramic powders and pottery is 0.5 millimeter, for realizing the full phase compensation of 360 degree, can utilize the multi-layer ceramics plate structure to realize.
Fig. 4 is the transmission channel phase error measured result before and after the compensation.This measured result is to be the transmission channel phase error of example metrophia compensation front and back with the four-way active transmitting antenna, therefore has three groups of interchannel phase error curves.Compensation prepass phase error is respectively 95 degree, 50 degree and 35 degree at 33GHz in the working frequency range of 33.5GHz, compensation back channel phases error is zero at 33GHz in the working frequency range of 33.5GHz substantially, and precision is in 5 degree.
Fig. 5 is the pitching and the orientation transmitting pattern measured result of four-way millimeter wave active antenna.Fig. 5-1 is an azimuth pattern, and Fig. 5-2 is pitch orientation figure.Have six directional diagram curves among each figure, being respectively operating frequency is the directional diagram curve of the angular range of 33GHz, 33.1GHz, 33.2 GHz, 33.3 GHz, 33.4 GHz, 33.5 GHz for ± 30 degree.
Fig. 6 is an active transmitting antenna closed loop compensation method flow diagram.First step carries out the measurement of interchannel phase error, can enter second step if error amount is zero, is zero can enter second step if the non-vanishing method of then utilizing medium to load of error amount is carried out phase compensation until the phase error in pitching and orientation; Second step, the transmitting pattern checking, if correct whole debugging end-of-job, if the incorrect first step of then getting back to forms the closed loop compensation method.
Embodiment 1
With phase error is that 95 degree are the operating procedure that example is introduced the active transmitting antenna phase error compensation of the present invention's proposition:
1. utilize vector network analyzer to measure the transmission channel phase error, thus the phase error theta between active transmitting antenna two passages when obtaining operating frequency and being 33GHz
1Be 95 degree.
2. the cuboid ceramic dielectric of selective rule loads, and thickness is 0.5 millimeter, and width and sidewall wide with shielding cavity fully contacts with the shielding cavity metal sidewall, and air shielding cavity height is 3 millimeters, is convenient to calculate the rectangular structure of choosing no changeover portion.At this moment, the effective dielectric constant ε of this structure
ReBe 1.583.
3. determine the length l of phase compensation section according to formula (1)
1, phase error theta
1Be 95 degree, λ when operating frequency is 33GHz
0Be 9.09 millimeters, effective dielectric constant ε
ReBe 1.583, these known parameters substitution formula (1) can be got
4. utilizing means such as mechanical wires cutting to obtain required length is 9.3 millimeters cuboid loaded medium, utilizes the low-loss glue that do not influence electromagnetic transmission that loaded medium is fixed on the final power amplifier chip and promotes to play between the level amplifier chip above the microstrip line of cascade effect.
5. the utilization network analyzer is measured the transmission channel phase error once more, compensation back phase error can satisfy the millimeter wave active antenna system index requirement of 5 degree, Fig. 4-1 is 95 to utilize the phase error measured result before and after the medium loaded microstrip line method compensation that the present invention proposes when spending for the channel phases error, and compensation back operating frequency is that the channel phases error of 33GHz is 1.37 degree.
6. in microwave dark room, measure the synthetic transmitting pattern of active transmitting antenna, the correctness that the synthetic launching beam of clarifying space forms.
Embodiment 2
With phase error is that 50 degree are that example is introduced the active transmitting antenna phase error compensation operating procedure that the present invention proposes, and its concrete operations step is consistent with embodiment 1, just compensator section length difference.Suppose phase error theta
2Be 50 degree, λ when operating frequency is 33GHz
0Be 9.09 millimeters, effective dielectric constant ε
ReBe 1.583, these known parameters substitution formula (1) can be got
Carry out phase compensation according to the operating procedure among the embodiment 1, Fig. 4-2 is 50 to utilize the phase error measured result before and after the medium loaded microstrip line method compensation that the present invention proposes when spending for the channel phases error, and compensation back operating frequency is that the channel phases error of 33GHz is 2.21 degree.
Embodiment 3
With phase error is that 35 degree are that example is introduced the active transmitting antenna phase error compensation operating procedure that the present invention proposes, its concrete operations step such as embodiment 1, just compensator section length difference.Suppose phase error theta
3Be 35 degree, λ when operating frequency is 33GHz
0Be 8.57 millimeters, effective dielectric constant ε
ReBe 1.583, these known parameters substitution formula (1) can be got
Carry out phase compensation according to the operating procedure among the embodiment 1, Fig. 4-3 is 35 to utilize the phase error measured result before and after the medium loaded microstrip line method compensation that the present invention proposes when spending for the channel phases error, and compensation back operating frequency is that the channel phases error of 33GHz is 4.57 degree.
Embodiment 4
With the operating frequency is that 36GHz is that example is introduced the active transmitting antenna phase error compensation operating procedure that the present invention proposes, its concrete operations step such as embodiment 1, just compensator section length difference.Suppose phase error theta
4Be 95 degree, λ when operating frequency is 36GHz
0Be 8.33 millimeters, effective dielectric constant ε
ReBe 1.583, these known parameters substitution formula (1) can be got
Carry out phase compensation according to the operating procedure among the embodiment 1.
Embodiment 5
To select polytetrafluoroethylene for use is that example is introduced the active transmitting antenna phase error compensation operating procedure that the present invention proposes, its concrete operations step such as embodiment 1, just dielectric material and compensator section length difference.Suppose phase error theta
5Be 35 degree, λ when operating frequency is 33GHz
0Be 9.09 millimeters, effective dielectric constant ε
ReBe 1.094, these known parameters substitution formula (1) can be got
(6)
Carry out phase compensation according to the operating procedure among the embodiment 1.