CN104218323A

CN104218323A - High-gain and low-loss X-band antenna design

Info

Publication number: CN104218323A
Application number: CN201310211007.3A
Authority: CN
Inventors: 葛俊祥; 成浩; 于兵; 潘安; 周勇
Original assignee: NANJING XINDA ELECTRONIC SCIENCE & TECHNOLOGY Co Ltd
Current assignee: NANJING XINDA ELECTRONIC SCIENCE & TECHNOLOGY Co Ltd
Priority date: 2013-05-31
Filing date: 2013-05-31
Publication date: 2014-12-17

Abstract

The invention discloses a design method of a high-gain and low-loss X-band marine navigation radar antenna with a length of 1,200 millimeters. In the design of the antenna, the technologies of a resonant waveguide aperture array antenna, a vertical polarization filter, a horn antenna, coaxial waveguide conversion and the like are mainly adopted. Compared with a conventional marine navigation radar antenna of the same length, the method has the advantages that a conventional long waveguide tube single-end feeding way is replaced by a short coaxial feeding way which is easy for matched resistance regulation, so that the transmission loss is reduced, the design difficulty of the antenna is lowered, and meanwhile the structural stability of the antenna is enhanced. Moreover, an aperture array is partitioned into four parts through array partition plates, so that side lobes of the antenna are reduced effectively.

Description

High-gain low-loss X-wave band autenna designs

Technical field

The invention belongs to Waveguide slot array antenna field, relate to a class X-wave band autenna design, specifically can be applicable to a kind of high-gain low-loss X-wave band autenna of ship-navigation radar.

Background technology

This antenna can be used for ship-navigation radar.Ship-navigation radar ensures the radar of ship's navigation, in order to observe the objects such as the water front of periphery, buoy and other boats and ships, and determines that its orientation is with collision free etc.This radar all installed by nearly all sea going boats and ships, and according to the requirement of the particular surroundings on sea and radar target acquisition accuracy, the antenna of ship-navigation radar generally all adopts the broom type wave beam under horizontal polarization.Easily realize horizontal polarization and broom wave beam because Waveguide slot array antenna has, and there is the characteristic such as high-gain and low sidelobe, be thus usually used in marine radar.For obtaining higher radar resolution, usually adopt longer slotted waveguide antenna, and be the radiation efficiency improving antenna, waveguide port feeding classification is often adopted for longer slotted waveguide antenna.Such feeding classification has oversize feed waveguide, and structure is loaded down with trivial details, adds the loss of feed simultaneously, also reduces the balance of antenna structure, adds the design difficulty of servo system.In addition, antenna load terminal also causes part electromagnetic energy to be absorbed by load, reduces the efficiency of antenna.Therefore, be necessary to improve the feeding classification of such antenna and antenna structure, under other index of guarantee meets the condition of practical application, reduce loss, improve the efficiency of antenna.

Summary of the invention

The invention provides the low-loss X-wave band autenna method for designing of a kind of high-gain, and design a kind of coaxial waveguide conversion equipment of simple impedance match and regulate.

The technical solution adopted for the present invention to solve the technical problems is: the low-loss X-wave band autenna of high-gain is formed primarily of resonant mode Waveguide slot array antenna, sectoral horn, perpendicular polarization filter, coaxial waveguide conversion equipment, short-circuit plunger and array demarcation strip.1. gap waveguide is that the narrow limit of main radiator waveguide has 54 R-joinings, and the distribution in gap realizes high-gain, low sidelobe and narrow horizontal beam.Sectoral horn is 2. in order to reduce wave beam, the raising gain of vertical direction.Perpendicular polarization filter is 3. in order to the electromagnetic wave of filtering perpendicular polarization.4. the coaxial waveguide conversion equipment that easy impedance matching regulates is the feed part of antenna, such air dielectric coaxial line does not have dielectric loss, and the length of feed line is shortened compared to the X-band of general 1200mm navigation antenna peculiar to vessel, greatly reduce loss.5. short-circuit plunger is positioned at waveguide two ends, and convenient antenna regulates test.Array demarcation strip being added in the field intensity Qiang district of gap waveguide and stronger district, for reducing the coupling between gap, the sidelobe level of antenna can being improved further.

The invention has the beneficial effects as follows: the coaxial line that the present invention adopts easy impedance matching to regulate is at the centre feed of antenna, compared with traditional ship-navigation radar antenna feed mode, reduce waveguide loss, adopt the Waveguide slot array antenna of resonant mode in addition, avoid the absorption loss of absorbing load to electromagnetic energy, improve the efficiency of antenna.Because antenna have employed apex drive structure, antenna is symmetrical, and thus the focus point of antenna is also distributing point and the run-on point of antenna, and more steady when antenna rotates, slit design is simpler.Meanwhile, adopt array demarcation strip to improve antenna sidelobe, structure is simple.

Accompanying drawing explanation

Fig. 1 high-gain low-loss X-wave band autenna structure three-dimensional schematic diagram.

Fig. 2 slot-waveguide configuration schematic diagram.

Fig. 3 sectoral horn cross sectional view.

Fig. 4 spatial vertical polarisation filter structural representation.

The structural representation of the conversion of Fig. 5 coaxial waveguide and feeding interface, polytetrafluoroethylene is used for fixing coaxial line.

The adjustable short-circuit plunger of Fig. 6 waveguide.

The standing-wave ratio simulation curve figure of the whole antenna of Fig. 7.

The E face of the whole antenna of Fig. 8 and H side gains directional diagram, its gain is up to 28.5dB.

Embodiment

With reference to Fig. 1.Above-mentioned antenna coaxial line is at the centre feed of gap waveguide.The metal materials such as whole antenna available copper, aluminium are made.

With reference to Fig. 2.Gap waveguide adopts long 22.86mm, the standard waveguide of wide 10.16mm.

With reference to Fig. 3.Desirable 0.5mm ~ the 0.8mm of thickness of sectoral horn.

With reference to Fig. 4.Desirable 0.5mm ~ the 1mm of thickness of perpendicular polarization filter.

With reference to Fig. 5.The inner wire radius size of coaxial line is 1.75mm, and the inside radius of outer conductor 6. size is 4.5mm, and filled media is air.7. one end of coaxial inner conductor uses helicitic texture, and this helicitic texture, mainly in order to coaxial inner conductor and waveguide are 8. fixed together, adopts this structure conveniently to regulate the inner wire of coaxial line simultaneously.In coaxial inner conductor and waveguide translation interface part 8., in order to make its impedance matching, have employed stepped construction 9., also can adopt other impedance matching structures such as gradual change type.In addition, waveguide 8. broadside add a screw 10. to improve impedance matching, also can improve impedance matching with many screws.In order to improve the bandwidth of antenna, with the coaxial outer conductor inside radius of Waveguide slot junction size is designed to 6mm.Coaxial line inside radius 6. with inside radius between changeover portion, add a medium (polytetrafluoroethylene), by regulating the shape of medium, can improve impedance matching, increases frequency bandwidth.Meanwhile, this medium also can guarantee that coaxial inner conductor is in the center of coaxial line all the time, does not produce skew.One end of coaxial line also using helicitic texture, this structure can either the outer conductor of fixing coaxial line, also can mounting medium .Coaxial waveguide converter loss in the present invention is very low, and the frequency bandwidth that standing wave is less than 1.2 is greater than 100MHz, meets practical application completely.

With reference to Fig. 6, adjustable short-circuit plunger size 0.1mm ~ 0.5mm less of the inside dimension of waveguide, ensure that plug can movement flexibly in waveguide, it also avoid that gap between piston and waveguide is excessive brings loss simultaneously.The mode of this short-circuit plunger can reduce the requirement to antenna machining accuracy, again regulates when being convenient to antenna measurement to antenna.

This antenna when assembling, first by part 1. Waveguide slot be arranged in sectoral horn structure groove 2., more 3. spatial vertical polarisation filter is arranged on the neck of horn structure.5. and array demarcation strip short-circuit plunger is then installed again .The main part of such antenna is just formed.Finally install the coaxial feed part of antenna more 4..Consider the feasibility that actual antennas is installed, feed part and antenna body adopt helicitic texture to combine.Overall installation diagram is shown in Fig. 1.

Length of the present invention is the frequency coverage of 1200mm, VSWR < 1.5 is 9.320GHz-9.448GHz.The gain of antenna is 28.5dB, and the first sidelobe level is less than-20.5dB, and the cross polarization within 10 ° is less than-51.5dB, and horizontal half-power beam width is 1.7 °, and vertical half-power beam width is 27 °.

Claims

1. a length is the high-gain low-loss X-wave band autenna design of 1200mm, form primarily of resonant mode Waveguide slot array antenna, sectoral horn, perpendicular polarization filter, coaxial waveguide conversion equipment, short-circuit plunger and array demarcation strip, it is characterized in that: antenna slots array three array demarcation strips separate, the coaxial feeding that antenna adopts easy impedance matching to regulate.

2. high-gain low-loss X-wave band autenna design according to claim 1, it is characterized in that: three array demarcation strips are placed on the centre position of Waveguide slot respectively, and the right and left of the middle 200mm-300mm of distance Waveguide slot, array is divided into 4 parts, demarcation strip can not cover the gap in waveguide.

3. high-gain low-loss X-wave band autenna design according to claim 1, it is characterized in that: adopt coaxial line at the center feed of resonant mode Waveguide slot array antenna, coaxial inner conductor one end adopts helicitic texture, and the insertion depth of coaxial inner conductor in gap waveguide can free adjustment.

4. high-gain low-loss X-wave band autenna design according to claim 1, it is characterized in that: the disk of conversion portion four decreasing radius of coaxial waveguide conversion equipment is formed, four disks are stacked on the rectangular waveguide broadside center of translation interface successively with one heart, and coaxial inner conductor passes from the center of four disks.