A kind of coupled structure of ridge waveguide to rectangular waveguideTechnical field
The invention belongs to antenna technical field, in particular relate to a kind of ridge waveguide to rectangular waveguide coupled structure.
Background technology
Frequency scan antenna have high gain, Sidelobe, large-angle scanning, at low cost, advantages of simple structure and simple, in recent years byIt is widely used in low altitude coverage radar, Search Radar, frequency scan antenna feeding network generally adds coupling using slow wave lineFeed structure, slow wave line require to be lost the features such as low reliability is high, and general common slow wave line includes waveguide slow wave line and band-likeLine slow wave line, ridge waveguide can be applied to rectangular waveguide couple feed structure in ridge waveguide slow wave line.
Ridge waveguide for rectangular waveguide, have many advantages, such as it is small with wide, Low ESR, size, in some rectangular wavesThe relatively difficult place of selvage guide battle array, ridge waveguide can replace the distribution of rectangular waveguide completion feeding network.Day is swept in order to meet frequencyThe large-angle scanning and Sidelobe characteristic of line, it is desirable that it is big, wide that slow wave line couple feed structure must have degree of coupling adjustable extentThe advantages that band works, coefficient of coup flatness is good.Under the premise of certain limited spaces, slow wave line couple feed structure needs are adoptedWith the form of ridge waveguide to rectangular waveguide, common ridge waveguide to rectangular waveguide couple feed structure is inclined slot couple feedStructure, such structure face the problems such as coefficient of coup flatness is poor, degree of coupling range is relatively narrow, in the case of cannot be satisfied wideband operationPerformance indicator requirement.
Invention content
According to problems of the prior art, the present invention provides a kind of coupled structure of ridge waveguide to rectangular waveguide,The coupled structure coefficient of coup flatness is good, coefficient of coup adjustable extent is big, meets the large-angle scanning of frequency scanning antenna and lowSecondary lobe characteristic.
The present invention uses following technical scheme：
A kind of ridge waveguide is to the coupled structure of rectangular waveguide, including ridge waveguide and rectangular waveguide；The cavity of the ridge waveguideIt is connected to the cavity of rectangular waveguide by coupling channel, the centre of the ridge waveguide, which is run through, transmission line.
Preferably, the ridge waveguide is single ridged waveguides, the both ends of the coupling channel respectively with the top surface of ridge waveguide and squareThe one end of shape waveguide connects.
It is further preferred that the coupling channel is oblique H-shaped channel comprising "-" type gap I, II and of "-" type gapConnection gap；The both ends of the connection gap are connect with the point midway in "-" type gap I, "-" type gap II respectively, a wordType gap I is mutually parallel with "-" type gap II；
Still more preferably, in the coupling channel, the length in the "-" type gap I and "-" type gap II isThe length of L1, connection gap are L2；Angle between the "-" type gap I and "-" type gap II and ridge waveguide width directionFor α, the angle between connection gap and ridge waveguide width direction is β；The midpoint in the "-" type gap I is point D, and two-end-point isThe midpoint of point F and point H, "-" type gap II are point E, and two-end-point is point G and point I；The length L1, length L2, angle α and folderThe size of angle beta is adjustable.
The beneficial effects of the present invention are：
1) in coupled structure of the invention, the cavity of ridge waveguide passes through the coupling channel of oblique H-shaped and the cavity of rectangular waveguideConnection；The coupling channel includes "-" type gap I, "-" type gap II and connection gap；The both ends of the connection gap pointIt is not connect with the point midway in "-" type gap I, "-" type gap II, "-" type gap I is mutually parallel with "-" type gap II.In the coupling channel, the length in the "-" type gap I and "-" type gap II is L1, and the length of connection gap is L2；InstituteIt is α, connection gap and ridge waveguide width to state the angle between "-" type gap I and "-" type gap II and ridge waveguide width directionAngle between direction is β；The midpoint in the "-" type gap I is point D, and two-end-point is point F and point H, "-" type gap IIMidpoint is point E, and two-end-point is point G and point I.
The coupling channel tool is there are two resonant path, i.e. path FDEG and path HDEI, the gap where the FDEG of pathThe length at edge indicates that the low-frequency resonant length of coupling channel, the length of the slot edge where the HDEI of path indicate coupling channelHigh-frequency resonant length, low-frequency resonant length and the bigger expression resonant bandwidth of gap of high-frequency resonant length are wider；Coupling channelThis structure, extend the gap of low-frequency resonant length and high-frequency resonant length, also just extend the range of resonant path, fromAnd the degree of coupling design of broadband character stabilization is realized, expand the adjustable range of the coefficient of coup.
Description of the drawings
Fig. 1 is the three-dimensional structure diagram of the coupled structure of the present invention.
Fig. 2 a are the vertical view of the coupled structure of the present invention.
Fig. 2 b are that the coupled structure of the present invention removes the vertical view of rectangular waveguide.
Fig. 3 is the side view of the coupled structure of the present invention.
Fig. 4 is the mark figure one of the coupling channel of the coupled structure of the present invention.
Fig. 5 a are the mark figure two of the coupling channel of the coupled structure of the present invention.
Fig. 5 b are the mark figure three of the coupling channel of the coupled structure of the present invention.
Fig. 6 is the S11 stickograms of the coupled structure in the embodiment of the present invention.
Fig. 7 is the S12 transmission coefficient figures of the coupled structure in the embodiment of the present invention.
Fig. 8 is the S13 coefficient of coup figures of the coupled structure in the embodiment of the present invention.
Reference numeral：1- ridge waveguides, 2- rectangular waveguides, 3- coupling channels, 31- "-" types gap I, 32- "-" types gapII, 33- connection gap.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, completeSite preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based onEmbodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every otherEmbodiment shall fall within the protection scope of the present invention.
Shown in a as shown in Figure 1, Figure 2, a kind of coupled structure of ridge waveguide to rectangular waveguide, including ridge waveguide 1 and rectangular waveguide 2；The cavity of the ridge waveguide 1 is connected to by coupling channel 3 with the cavity of rectangular waveguide 2, and the centre of the ridge waveguide 1, which is run through, biographyDefeated line 4.
The ridge waveguide 1 is single ridged waveguides, the both ends of the coupling channel 3 respectively with the top surface of ridge waveguide 1 and rectangular waveLead 2 one end connection.
As shown in Figure 2 b, the coupling channel 3 is oblique H-shaped channel comprising "-" type gap I 31, "-" type gap II32 and connection gap 33；The both ends of the connection gap 33 middle point with "-" type gap I 31, "-" type gap II 32 respectivelyConnection is set, "-" type gap I 31 is mutually parallel with "-" type gap II 32.
As shown in figure 4, in the coupling channel 3, the length in the "-" type gap I 31 and "-" type gap II 32 isThe length of L1, connection gap 33 are L2；The "-" type gap I 31 and "-" type gap II 32 and 1 width direction of ridge waveguide itBetween angle be α, the angle between 1 width direction of connection gap 33 and ridge waveguide is β；The midpoint in the "-" type gap I 31For point D, two-end-point is point F and point H, and the midpoint in "-" type gap II 32 is point E, and two-end-point is point G and point I；
The tool of the coupling channel 3 is there are two resonant path, i.e. path FDEG and path HDEI, the gap where the FDEG of pathThe length at edge indicates that the low-frequency resonant length of coupling channel 3, the length of the slot edge where the HDEI of path indicate that coupling is logicalThe high-frequency resonant length in road 3, low-frequency resonant length and the bigger expression resonant bandwidth of gap of high-frequency resonant length are wider；Pass through tuneThe size for saving length L1, length L2, angle α and angle β realizes large-scale degree of coupling design.
The coupled structure in the present invention is illustrated with reference to embodiment.
Embodiment 1：
The working frequency range of the coupled structure of the present embodiment is 15GHz~20GHz, and the degree of coupling is -11dB.As shown in Figure 1, figure1 for ridge waveguide of the present invention to the stereogram of the couple feed structure of rectangular waveguide, the direction shown in A is expressed as signalInput port direction, the direction shown in B are expressed as signal straightthrough port direction, and the direction shown in C is expressed as coupled signal outputMouth direction.
As shown in Fig. 2 a, Fig. 3, ridge waveguide 1 is single ridged waveguides, its ridge wide Td=1.5mm, narrow side Th=5mm, the side of ridgeHem width degree Tw=1.5mm, ridge depth Tb=4.2mm.The narrow side Ta=4.5mm of rectangular waveguide 2, broadside Tk=12.95mm, coupling are logicalThe depth dd=0.8mm in road.
As shown in figure 4, point D is the central point in "-" type gap I 31, point E is the central point in "-" type gap II 32, point FThe both sides of line DE are located at point G, point H and point I are located at the both sides of line DE, and path FDEG and path HDEI are in" Z " font, there are two resonant path FDEG and HDEI, wherein FD=EG=HD=EI=3.9mm, DE=for coupling channel toolAngle α=69.3 ° between 4.6mm, "-" type gap I 31 and "-" type gap II 32 and 1 width direction of ridge waveguide, connecting sewingAngle β=71.7 ° between 1 width direction of gap 33 and ridge waveguide.
Illustrate that the coupled structure of the present embodiment meets the working performance of antenna below by emulation.
As shown in fig. 6, Fig. 6 is the S11 stickograms of the coupled structure of the present embodiment.It can be obtained by Fig. 6, in work frequencyRate 15~20GHz bandwidth reflection coefficient S11 indexs are better than -20dB, meet the working performance requirement of scanning antenna.
As shown in fig. 7, Fig. 7 is the S12 transmission coefficient figures of the coupled structure of the present embodiment.It can be obtained by Fig. 7, in work frequencyTransmission coefficient S12 fluctuating 0.1dB or so in bandwidth, fluctuating very little meet the work of scanning antenna in rate 15~20GHz bandwidthPerformance requirement.
As shown in figure 8, Fig. 8 is the S13 coefficient of coup figures of the coupled structure of the present embodiment.It can be obtained by Fig. 8, in work frequencyThe degree of coupling rises and falls from -10.82dB to -11.55dB in rate 15~20GHz bandwidth, rises and falls very small, and coefficient of coup flatness is good,Meet the working performance requirement of scanning antenna.
As shown in Fig. 5 a, Fig. 5 b, point F and point G is located at the both sides of line DE, and point H and point I are located at line DE'sBoth sides, path FDEG and path HDEI are in " Z " font, and the length of the slot edge where the FDEG of path indicates coupling channel 3Low-frequency resonant length, the length of the slot edge where the HDEI of path indicates that the high-frequency resonant length of coupling channel 3, low frequency are humorousThe gap size of length of shaking and high-frequency resonant length corresponds to the adjustable range size of the coefficient of coup；Therefore, in the present embodimentCoupled structure can be by the size of adjustment length L1, length L2, angle α and angle β, to increase low-frequency resonant length and harmonic high frequencyThe gap for length of shaking increases the adjustable range of the coefficient of coup.
In conclusion the coefficient of coup flatness of the coupled structure of the present invention is good, coefficient of coup adjustable extent is big, meetThe large-angle scanning and Sidelobe characteristic of frequency scanning antenna.