CN209526203U - Broadband double-circle polarization micro-strip turns waveguide feed antenna system - Google Patents

Abstract

The utility model discloses a kind of antenna systems, comprising: electric bridge, upper layer metal, top substrate layer, underlying substrate, lower metal, radiation patch, mode converter, circular waveguide, metallic vias；The antenna system is Multilayer Structure, with being followed successively by upper layer metal from top to bottom, top substrate layer, underlying substrate, lower metal；The radiation patch is located on the upside of the top substrate layer, and the mode converter is placed in the top of the radiation patch and is connected to the circular waveguide above it；The electric bridge constitutes feeding network, and two ports of the electric bridge are between the top substrate layer and the underlying substrate.Broadband, double-circle polarization can be realized in millimeter wave frequency band using the feed antenna system of the utility model, guarantee that transmitting-receiving port has good isolation, the mode conversion that microstrip antenna turns circular waveguide is realized simultaneously, structure is simple and efficient, and circular polarisation performance is not changed, the feed that can be used as multiple types antenna uses.

Description

Broadband double-circle polarization micro-strip turns waveguide feed antenna system

Technical field

The utility model relates to antenna technical field, in particular to a kind of broadband double-circle polarization 77GHz micro-strip turns waveguide Feed antenna system.

Background technique

In the prior art, millimetre-wave radar technology is in car radar, safety check imaging, scene police radar, oil tank gauging etc. Field has been widely used.The main advantage of millimetre-wave radar technology has: having very high tracking accuracy and spatial discrimination Rate；With very high DOPPLER RESOLUTION and rate accuracy；With very strong target identification ability and imaging capability；With good Anti-interference ability.

The Radar Technology of early stage based on pulse radar technology, but pulse radar technology have the shortcomings that it is obvious: for example Transmission power requires very big, transmitting-receiving need switching, have detection blind area, is bulky, being easy to be trapped etc..And continuous wave (Continuous Wave, abbreviation CW) radar overcomes these disadvantages, simple with structure, that size is small, power is low etc. is excellent Point, thus have been more and more widely used.Continuous wave radar can there are many modulation systems, wherein with CW with frequency modulation (frequency modulation Continuous Wave, abbreviation FMCW) radar is most widely used.Relative to pulse Radar system, frequency modulated continuous wave radar since there is no blind range zone, receiving sensitivity height, strong antijamming capability, high resolution, The features such as power requirement is small, structure is simple and be increasingly taken seriously.However there are still many for the development of the technology of continuous wave radar Challenge, firstly, since frequency modulated continuous wave radar needs the end send-receive (TX/RX) to work at the same time, to keep send-receive (TX/RX) it is not interfere with each other between port to obtain good working performance, to the transmitting-receiving between the port send-receive (TX/RX) Interport isolation has higher requirement, so that the design for rear end millimetric wave device adds difficulty；Secondly, CW with frequency modulation thunder The resolution ratio reached is determined by the bandwidth of radar antenna, in order to guarantee receiving port sensitivity with higher and resolution ratio, is received Antenna needs as far as possible using broad-band antenna, so that the design of transceiver antenna brings challenge.

In the practical application of millimetre-wave radar, such as oil tank gauging system, the requirement to antenna be with high-gain and Lesser field angle (3 °) so can be improved link gain, increase range and reduce interference.In such application scenarios, thoroughly Mirror antenna, electromagnetic horn, reflector antenna etc., which become, more preferably to be selected, because in 77GHz frequency range, the size of above-mentioned these antenna It is usually all smaller, actual processing and application can be carried out.The radio frequency chip of the millimetre-wave radar system core is mostly monolithic at present Microwave integrated circuit (Monolithic Microwave Integrated Circuit, abbreviation MMIC), packing forms are with ball Based on shape pin grid array (Ball Grid Array, abbreviation BGA) encapsulation.As it can be seen that the radio frequency system of radar can be divided into Using MMIC, feeder line, antenna as the feed system of core and using lens/loudspeaker as the focusing system of core.The transmitting-of radio frequency chip It receives feeder line after the port (TX/RX) and Antenna Design is most important, how overriding challenge is by 77GHz frequency band signals Traditional waveguiding structure or other stereochemical structures are converted to from planar transmission cable architecture, further motivate lens or loudspeaker, from And it realizes high-gain and radiates；Secondly, the electromagnetic wavelength of 77GHz only has 3.9mm, either printed circuit board (Printed Circuit Board, abbreviation PCB) technique or numerical control (Computer Numerical Control, abbreviation CNC) technique, Machining accuracy has a great impact to the design of antenna, how to design the antenna of high robust to adapt to corresponding machining accuracy, It is another key point.In CW with frequency modulation (FMCW) radar system of millimeter wave frequency band, what Antenna Design mainly faced Challenge includes: bandwidth of operation；Send-receive end isolation；Planar transmission cable architecture is to the conversion of transmitting/reception structure；Robust Property design.

Referring to shown in Figure 1A-Fig. 1 D, in the prior art, in order to realize transceiver insulation, antenna feeding network system is usual The scheme of use has: 3dB bridge solution as shown in Figure 1A；Circulator scheme as shown in Figure 1B；Coupling as shown in Figure 1 C Device scheme；Two-antenna scheme as shown in figure iD.

However, inventor it has been investigated that, in circulator scheme, under 77GHz frequency range, Ferrite Material characteristic can be sent out Raw great change, thus it is relatively difficult using PCB technology realization.In two-antenna scheme, receives and transmitting uses an antenna respectively； In theory, if two antennas from it is enough remote, isolation can be accomplished very well；But come as product design It says, 2 antennas certainly will need double space；Especially in the Radar Design of 77GHz, in order to realize it is farther communication away from From the size of antenna is all larger, and 2 antennas certainly will will occupy larger space, keeps product structure more too fat to move.Therefore, existing skill Circulator or double antenna form are used in order to realize transceiver insulation in art, wherein circulator will lead to the gain loss of antenna, And dual-antenna system can increase antenna size, and since its directive property problem can equally bring the gain loss of antenna.

For CW with frequency modulation (FMCW) radar since receiving end and transmitting terminal work at the same time, antenna mostly uses linear polarization day Line causes transmitting-receiving interport isolation poor and influences antenna performance.To solve this problem, the mode of addition circulator can be used Improve transmitting-receiving interport isolation, but circulator can bring additional decaying to reduce the sensitivity of antenna；Alternatively, transmitting-receiving Different antennas is respectively adopted in end, but this mode will increase equipment volume again, and can reduce because of directive property problem Antenna gain.

Shown in Figure 2, in the prior art, micro-strip turns waveguide frequently with the scheme of square circle conversion, and circular waveguide is due to right There is polarization degeneracy phenomenon in title property, can excite various modes, and can be easier to excite due to the discontinuity of circular waveguide Higher mode；And since the main mould TE10 mould of rectangular waveguide and the main mould TE11 mould of circular waveguide are extremely similar, pass through square shown in Fig. 2 The generation that mode converts and reduces higher mode can be well realized in circle transformational structure, therefore has preferable working performance； But this kind of scheme shown in Fig. 2 destroys circular symmetry and can not generate circularly polarised wave.It is shown in Figure 3, in the prior art In, also frequently by microstrip probe energisation mode, the depth for adjusting short-circuit plunger carries out impedance matching, makes to be coupled to circular waveguide In energy reach maximum；But need to add short-circuit plunger in the scheme in Fig. 3, give it under 77GHz millimeter wave frequency band Fabrication design brings certain difficulty, and since it is directly from microstrip transitions to circular waveguide, is easy to generate higher mode, and its Bandwidth of operation is also unable to reach the design requirement of system.

In the prior art, microstrip antenna generallys use the mode of single layer patch directly excitation, and such mode designs, processes letter It is single, but bandwidth of operation is relatively narrow, usually less than 5%, and cause robustness not high due to narrower bandwidth, vulnerable to machining accuracy It restricts, can not achieve broadband design.

Utility model content

Based on this, for solve in the prior art the technical issues of, spy proposes a kind of antenna system.

The antenna system include electric bridge, upper layer metal, top substrate layer, underlying substrate, lower metal, radiation patch Piece, mode converter, circular waveguide；The antenna system has Multilayer Structure, with being followed successively by upper layer metal from top to bottom, upper layer Substrate, underlying substrate, lower metal；The radiation patch is located on the upside of the top substrate layer, and the mode converter is placed in The top of the radiation patch and it is connected to the circular waveguide above it；Two ports of the electric bridge are located at the upper layer Between substrate and the underlying substrate.

In one embodiment, the mode converter is round table-like waveguide, and the mode converter is completed microstrip line and arrived The mode transition of round table-like waveguide and most Zhongdao circular waveguide realizes TM01 mode to TE11 mould under the excitation of the radiation patch The gradual change of formula.

In one embodiment, wherein be to the upper layer metal internal diameter side that is cyclic annular and being located at the mode converter At；The antenna system has multiple metallic vias, and the metallic vias position is arranged in a ring, is centered around the upper layer metal At the outer on ground, top substrate layer described in metallic vias break-through from top to bottom and the underlying substrate.

In one embodiment, the electric bridge constitutes feeding network, and the electric bridge has first port, second port, the Three ports, the 4th port；The first port, second port are respectively receiving port or emission port；The third port and 4th port between the top substrate layer and the underlying substrate, the radiation patch lower section and with the spoke It penetrates between patch and is separated by the top substrate layer.

In one embodiment, the electric bridge is 3dB electric bridge；By the first port or second port input signal, lead to Crossing the 3dB electric bridge, that the both-end that amplitude is equal and phase difference is 90 degree is generated at the third port, the 4th port is sharp Signal is encouraged, to generate circularly polarised wave；The third port and the 4th port pass through coupling feed way to the radiation Patch is fed.

In one embodiment, the antenna system is applied in frequency modulated continuous wave radar；

In one embodiment, the working frequency of the antenna system is 77GHz；

It in one embodiment, can be using the antenna system as lens antenna or the feed of electromagnetic horn.

Implement the utility model embodiment, will have the following beneficial effects:

The utility model uses coupling feed way, and it is equal and 90 degree of phase phase difference to generate amplitude by electric bridge feeding network Dual-port signal while excitation radiation patch are to generate circularly polarised wave, and utilize the polarization reversal of circularly polarised wave reflection echo Characteristic realizes the polarization isolation of sending and receiving end, guarantees the isolation of transmitting-receiving port.The antenna system of the utility model further includes one kind Simple, functional, high conversion efficiency the round table-like mode converter of structure realizes microstrip line to round table-like waveguide, most Zhongdao The mode transition of standard circular waveguide realizes micro-strip by addition mode converter under the incentive action of wideband microstrip antenna Antenna reduces coupling of the waveguide to microstrip antenna by TM01 mode to the gradual change of TE11 mode, while reducing higher mode It generates, therefore the bandwidth of antenna system is directly determined by the excitation of double-circle polarization microstrip antenna, reduces the coupling of traditional circular waveguide Interference.

The utility model proposes broadband, double-circle polarization, microstrip transitions to circular waveguide feed antenna system, sending and receiving end The double rotational directions of signal can guarantee that antenna system transmitting-receiving port keeps higher isolation, while antenna system utilizes a kind of structure Very simple microstrip transitions, can be with as the feed of lens antenna or electromagnetic horn to the gradual transition transformational structure of waveguide Improve the gain of antenna and the sensitivity of receiver.

Detailed description of the invention

In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only It is some embodiments of the utility model, for those of ordinary skill in the art, in the premise not made the creative labor Under, it is also possible to obtain other drawings based on these drawings.

Wherein:

Figure 1A is the schematic diagram for the antenna feeding network system realized in the prior art using 3dB electric bridge.

Figure 1B is the schematic diagram for realizing antenna feeding network system using circulator in the prior art.

Fig. 1 C is the schematic diagram for realizing antenna feeding network system using coupler in the prior art.

Fig. 1 D is the schematic diagram for realizing antenna feeding network system using double antenna in the prior art.

Fig. 2 is the circle transformational structure schematic diagram of square in the prior art；

Fig. 3 A is that the micro-strip of microstrip probe excitation in the prior art turns waveguiding structure main view；

Fig. 3 B is that the micro-strip of microstrip probe excitation in the prior art turns waveguiding structure left view；

Fig. 4 is the three-dimensional view of antenna system in the utility model；

Fig. 5 is the side view of antenna system in the utility model；

Fig. 6 is the top view of antenna system in the utility model；

Including, antenna system 1, electric bridge 2, upper layer metal 3, top substrate layer 4, underlying substrate 5, lower metal 6, Radiation patch 7, mode converter 8, circular waveguide 9, metallic vias 10, first port 21, second port 22, third port 23, Four ports 24.

Specific embodiment

The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without creative efforts Every other embodiment obtained, fall within the protection scope of the utility model.

The utility model discloses a kind of work under 77GHz frequency range there is high-isolation, broadband, micro-strip to turn waveguide Feed antenna system.

Referring to fig. 4, shown in 5, the antenna system 1 include electric bridge 2, upper layer metal 3, top substrate layer 4, underlying substrate 5, Lower metal ground 6, radiation patch 7, mode converter 8, circular waveguide 9, metallic vias 10；

The side view of antenna system 1 shown in Figure 5, the antenna system 1 are Multilayer Structure, from top to bottom successively For upper layer metal 3, top substrate layer 4, underlying substrate 5, lower metal 6；The radiation patch 7 is located at the top substrate layer 4 Upside, the mode converter 8 are placed in 7 top of radiation patch and are connected to the circular waveguide 9 above it；Wherein, The mode converter 8 is round table-like waveguide, is converted for realizing the gradual change of TM01 mode to TE11 mode；

It wherein, 3 is the upper layer metal cyclic annular and be located at the internal diameter edge of the mode converter 8；The antenna System 1 has multiple metallic vias 10, and the metallic vias position 10 is arranged in a ring, with being centered around the upper layer metal 3 it is outer At, top substrate layer 4 and the underlying substrate 5 described in the break-through from top to bottom of metallic vias 10.The metallic vias 10 is used In the generation of reduction surface wave, and there is no metallic vias 10 so that it is guaranteed that not producing at the feeding microstrip line of 2 feeding network of electric bridge Raw interference.

Referring to fig. 4 shown in -6, the electric bridge 2 constitutes feeding network, and the electric bridge 2 has first port 21, second port 22, third port 23, the 4th port 24；Wherein, the first port 21, second port 22 are respectively receiving port or transmitting terminal Mouthful, i.e., when the first port 21 is receiving port, the second port 22 is emission port, or works as the second port 22 first ports 21 when being receiving port are emission port；The third port 23 and the 4th port 24 are located at described Between top substrate layer 4 and the underlying substrate 5, the radiation patch 7 lower section and be separated by institute between the radiation patch 7 State top substrate layer 4；

Wherein, the electric bridge 2 is 3dB electric bridge；By 22 input signal of the first port 21 or second port, by described 3dB electric bridge, which generates the both-end excitation that amplitude is equal and phase difference is 90 degree in the third port 23, the 4th port 24, to be believed Number, to generate circularly polarised wave；It is separated by between the third port 23 and the 4th port 24 and the radiation patch 7 described Top substrate layer 4 feeds the radiation patch 7 by coupling feed way；

3dB electric bridge is also referred to as same frequency combiner, can carry out along a determining direction of transmission line to transimission power The input signal of electric bridge input port is divided into two constant amplitudes and has signal and the output of 90 degree of phase differences by continuous sampling；3dB The utilization rate of output signal can be improved for multi signal combining for electric bridge；

Antenna system 1 in the utility model uses multiple sliding cover, the feedback being made of coupling feed way electric bridge 2 Electric network feeds radiation patch 7, realizes impedance matching, the work of the antenna system 1 using impedance match technique appropriate 50%-70% can be promoted compared with single layer feeding classification by making bandwidth, not only increase system bandwidth of operation, also improve the robust of system Property.

The antenna system 1 is applied in frequency modulated continuous wave radar, the antenna system 1 is dual circularly polarized antenna, thunder Rotation direction can be changed when reflecting up to the circularly polarised wave launched, utilize polarization isolation existing for circular polarized antenna left-right rotary To guarantee to receive and dispatch the isolation of port.The generation that surface wave is reduced by addition metallic vias 10 is tied by emulating this visible kind Structure improves the beamwidth of antenna, so that the beamwidth of antenna has reached 16%.

Mode converter 8 in the utility model is that a kind of structure is simple, micro-strip of high conversion efficiency turns the transition of waveguide Structure realizes the conversion of microstrip line to circular waveguide 9.Due to the limitation of working frequency, many conversion regimes in the prior art It cannot be used under 77GHz frequency range, such as common micro-strip turns moment round transition mode used by waveguide, because of rectangular waveguide TE10 mould and circular waveguide TE11 mode are very close, and the structure of rectangular waveguide is but also with enough bandwidth, can be to avoid high order The generation of mould.But in the technical solution of the utility model, rectangular waveguide cannot be used due to needing to carry out circular polarisation transmission Structure can motivate higher modes using the direct transition of circular waveguide again, and the close coupling effect of circular waveguide can be to radiation patch Performance parameter have an impact, reduce bandwidth of operation.Therefore, efficient, simple mode converter is most important, the utility model Technical solution realize that micro-strip is converted by the gradual change of TM01 mode to TE11 mode by addition mode converter 8, and it is common round Waveguide is directly converted to be obviously improved compared to its bandwidth, can reduce the interference to radiation patch 7 to the maximum extent.

The directional diagram that micro-strip is radiate from circular waveguide can slightly deteriorate, and being on the one hand that antenna port return loss is poor leads It causes, is on the other hand that changeover portion still has certain higher order mode generation and generates adverse effect to directional diagram, passes through increase The height or lengthening circular waveguide length of mode converter (rotary table waveguide) make higher mode decay or use in transmission process In the part of mode converter (rotary table waveguide), addition ripple struction can effectively reduce influence of the higher mode to directional diagram.

In view of processing factors, the technical solution of the utility model is accelerated using circular waveguide 9 and mode converter 8 is extended The decaying of higher modes, extend the visible extension rear direction figure symmetry of front-rear direction figure comparing result by waveguide has with gradeization Improve, is also promoted from side reflection shaft than performance, by the whole axis of antenna system 1 3dB axis ratio more visible than simulation result Bandwidth has reached 10%, functional.

Implement the utility model embodiment, will have the following beneficial effects:

The utility model discloses a kind of feed antenna systems of 77GHz double-circle polarization microstrip transitions to circular waveguide, imitate True axis is 10% than three dB bandwidth, has reached the requirement of broadband circular polarisation, has had better robustness, compared to linear polarized antenna With better anti-interference ability.The characteristics of changing rotation direction using circular polarisation echo has inborn polarization isolation advantage, protects The isolation of transmitting-receiving port is demonstrate,proved.Antenna system has that structure is simple, mode converter of high conversion efficiency simultaneously, may be implemented Micro-strip reduces the interference of higher mode to the conversion of waveguide, ensure that the broadband requirement of antenna system, and antenna system integrally has Standby good radiance, is widely used, and the feed that can be used as a variety of antennas such as lens antenna, electromagnetic horn uses, effectively Improve the gain of antenna and the sensitivity of receiver.

Above embodiments are only to illustrate the technical solution of the utility model, rather than its limitations；Although referring to aforementioned reality Example is applied the utility model is described in detail, those skilled in the art should understand that: it still can be to preceding Technical solution documented by each embodiment is stated to modify or equivalent replacement of some of the technical features；And these Modify or replace, can't make corresponding technical solution essence be detached from various embodiments of the utility model technical solution spirit and Range.

Claims (7)

1. a kind of antenna system, which is characterized in that

The antenna system include electric bridge, upper layer metal, top substrate layer, underlying substrate, lower metal, radiation patch, mould Formula converter, circular waveguide；The antenna system have Multilayer Structure, with being followed successively by upper layer metal from top to bottom, top substrate layer, Underlying substrate, lower metal；The radiation patch is located on the upside of the top substrate layer, and the mode converter is placed in the spoke It penetrates the top of patch and is connected to the circular waveguide above it；Two ports of the electric bridge be located at the top substrate layer with Between the underlying substrate.

2. antenna system according to claim 1, which is characterized in that

Wherein, the mode converter is round table-like waveguide, and the mode converter completes microstrip line to round table-like waveguide and most The mode transition of Zhongdao circular waveguide realizes the gradual change of TM01 mode to TE11 mode under the excitation of the radiation patch.

3. antenna system according to claim 2, which is characterized in that

It wherein, is to the upper layer metal internal diameter edge that is cyclic annular and being located at the mode converter；The antenna system tool There are multiple metallic vias, the metallic vias position is arranged in a ring, is centered around at the outer on the upper layer metal ground, the metal Top substrate layer described in via hole break-through from top to bottom and the underlying substrate.

4. antenna system according to claim 1, which is characterized in that

Wherein, the electric bridge constitutes feeding network, and the electric bridge has first port, second port, third port, the 4th end Mouthful；The first port, second port are respectively receiving port or emission port；The third port and the 4th port position Between the top substrate layer and the underlying substrate, the radiation patch lower section and be separated by between the radiation patch The top substrate layer.

5. antenna system according to claim 4, which is characterized in that

Wherein, the electric bridge is 3dB electric bridge；By the first port or second port input signal, existed by the 3dB electric bridge The both-end pumping signal that amplitude is equal and phase difference is 90 degree is generated at the third port, the 4th port, to generate Circularly polarised wave；The third port and the 4th port feed the radiation patch by coupling feed way.

6. antenna system according to claim 1-5, which is characterized in that

The antenna system is applied in frequency modulated continuous wave radar.

7. antenna system according to claim 1 or 2, which is characterized in that

The working frequency of the antenna system is 77GHz.