CN102394359A - Multilayer micro-strip flat-plate array antenna with symmetric beams - Google Patents

Abstract

The invention relates to a multilayer micro-strip flat-plate array antenna with symmetric beams, which consists of a radiation layer, a feeder layer and a reflection plate, wherein radiation patches are symmetrically distributed on an inner surface of the radiation layer, and the radiation patch array is totaled in 18 units of 3*6; the feeder layer is arranged between the radiation layer and the reflection plate, a distance between every two adjacent layers is a quarter wavelength, a grounding surface of the feeder layer is provided with 18 H-shaped coupled gaps in a form of 3*6, a micro-strip feeder line is arranged on the feeder surface of the feeder layer, on a micro-strip feeder-line network, energy is allocated by a first-level power distributor to a second-level power distributor and is opposite to a phase position, finally the energy is allocated to each radiation unit through a serial impedance matching circuit, the reflection plate is a metal plate and forms an inner surface of an antenna shell, the radiation layer also has a function of an antenna cover, and the entire antenna is completely arranged inside a closed shell except a connector.

Description

A kind of little band flat plate array antenna of multilayer of wave beam symmetry

Technical field

The invention belongs to antenna technical field, be specifically related to a kind of little band flat plate array antenna of multilayer of wave beam symmetry, when design, the secondary lobe of one dimension serial feed planar array antenna wave beam is passed through the design realization left-right symmetric of feed.

Technical background

At present, micro-strip array antenna is widely used at aspects such as radar, remote sensing, communications.The single layer microstrip antenna is in light weight with it, and thickness is little, and characteristics such as easy syntype obtain paying attention to, but compare with common microwave antenna, and the general frequency band of microstrip antenna is narrow, and is lossy, thereby gain is not high.When frequency one regularly, the broader bandwidth of thick substrate, gain are higher, the substrate broader bandwidth gain that dielectric constant is more little is higher.Because the representative value of microstrip antenna bandwidth is the magnitude of a few percent, so band limited is one of shortcoming of microstrip antenna.

For desirable planar array antenna, different feeding classifications directly influences antenna different directions diagram shape.Theoretical according to Pattern Synthesis, the resulting antenna far-field pattern of equiphase feeding classification of amplitude symmetry also is symmetrical.But in the practical application of micro-strip array antenna, normally feeding network and array element all are in the same side.Because this will produce certain radiation in radio frequency band microstrip line; The mutual coupling that the radiation field mutual superposition of the radiation field of its feeder line and radiating element produces; Not only can influence the cross polarization and the isolation of antenna; And influencing the gain of main lobe, the secondary lobe of antenna far-field pattern also can irregularly be arranged simultaneously.During particularly less when antenna array unit number, wave beam broad, the formed directional diagram main beam of micro-strip paster antenna can be out of shape deterioration, thereby can not satisfy the practical application that some required direction figure is symmetrically distributed.About the problem of array antenna feed, forefathers have done a large amount of work.General feeding network all is wiring around radiation fin, the mutual coupling problem of keeping away unavoidable feeder line and radiating element like this.The method that adds the coupling shielding conductor can make single microstrip line radiant power be significantly less than the power when not adding shielding conductor, but in actual engineering design often because the restriction of microstrip array radiating element spacing makes this method be difficult to realization.

Summary of the invention

The technical problem that the present invention will solve is: overcome the deficiency of existing micro-strip array antenna band limited and feeding classification technology, design the little band flat plate array antenna of a kind of wave beam symmetry multilayer, this aerial loss is little, simple in structure, processing is simple.

Realize that technical scheme of the present invention is: the little band flat plate array antenna of multilayer of wave beam symmetry is designed to three layers, form by radiating layer, feed layer and reflecting plate, and the radiation patch that on the inner surface of radiating layer, is symmetrically distributed, the radiation patch array is 3 * 6 totally 18 unit; Said feed layer is between radiating layer and reflecting plate, and every interlamellar spacing is a quarter-wave, and feed layer is a ground plane towards the one side of radiating layer; One side towards reflecting plate is the microstrip feed line face, on ground plane, offers 3 * 6 coupling slits of totally 18 H shapes, arranges microstrip feed line at the feeder line face; The microstrip feed line network is by distributing point, first order power splitter, two second level power splitters; Serial feed terminated line and transmission line are formed; Distributing point is used to weld semi-flexible cable, and energy is distributed to two second level power splitters and made two second level power splitter phase places opposite through first order power splitter, gives each radiating element through serial impedance matching circuit with energy distribution at last; Said reflecting plate is a metallic plate; Constitute the inner surface of antenna housing, said radiating layer possesses the function of radome simultaneously, and entire antenna is in except that a connector among the airtight housing entirely.

Symmetric form is adopted in feed layer of the present invention design, reduces the influence of feed transmission line array directional diagram, constitutes the beam pattern of symmetry, and the center of gravity of the radiation patch of on the geometric center of the radiating slot that adheres on the ground plane and radiating layer, adhering to overlaps; Make the microstrip feed line energy in the feeder line layer be coupled to radiation patch and then radiate, eliminated the coupling influence between feeder line self radiation and the radiating element through the coupling slit.

Feeding classification at microstrip feed line face azimuth dimension feeder line is a serial feed; The size of 1/4 impedance matching line through regulating each joint realizes the distribution of amplitude, and wherein two row's azimuth dimension and the pitching fibrillar center feeder line near top edge and lower limb distributes with axial symmetry, and two to arrange feeder line feed in the opposite direction for this; The feed of middle row's feeder line the right and left is in the opposite direction; In the pitching dimension, regulate power splitter, realize amplitude distribution that through two second level power splitter is through not isometric asymmetric double port network and two second level power splitter cascades; Realize between two second level power splitters 180 ° of phase phasic differences, thus the phase difference that feeder line produced that collocation structure is symmetrically distributed.Because the energy of the microstrip feed line in the feeder line layer is to be coupled to radiation patch and then to radiate through the coupling slit; The radiation field of microstrip feed line itself does not influence radiation patch; And microstrip feed line itself also is a symmetry arrangement; Therefore this structure has just been eliminated the coupling influence between feeder line self radiation and the radiating element, thereby directional diagram also is symmetrical.

By symmetrical little band flat plate array antenna of multilayer and the prior art contrast of wave beam of the present invention that technique scheme constitutes, the beneficial effect that has is:

Prior art places same plane and feeder line to arrange radiation patch and feeder line to be unsymmetric structure usually, and often symmetry is bad for the antenna actual measurement directional diagram of this structure, and gain is also because radiation patch and feeder line mutual coupling influence reduces.The present invention can reduce the mutual coupling between radiation patch and feeder line through unique feed design, realizes the good symmetry of wave beam.

Description of drawings

Fig. 1 is a radiating layer radiating element distribution map

Fig. 2 is feed layer ground plane coupling slit figure

Fig. 3 is a feed layer microstrip feed line distribution map

Fig. 4 is radiating layer feed layer and reflecting plate assembly sketch map

Fig. 5 is a pitching dimension actual measurement directional diagram

Fig. 6 is an azimuth dimension actual measurement directional diagram

Embodiment

Below in conjunction with accompanying drawing content of the present invention is carried out clear, detailed explanation.

Fig. 1 is the radiating element distribution map of radiating layer 11.Radiation patch 1 is arranged in the inner surface of radiating layer according to the theoretical result of calculation of Pattern Synthesis among Fig. 1, is symmetrical distribution.The radiation patch array is 3 * 6 totally 18unit.Screw hole 2 is distributed in the radiating layer edge.

Fig. 2 isfeed layer 15 ground planes coupling slit figure.This layer is printed on the one side of centre feed layer, and theground plane 14 offeed layer 15 is positioned at the place, below of radiating layer.The slit 6 that wherein is coupled is shaped as " H " shape, and the coupling gap array is 3 * 6 totally 18, the center of gravity coincidence of the center in each slit 6 and radiation patch 1.What arrow 3 was indicated is the polarised direction of antenna.Viahole 4 is the welding reservation of cable with via hole 5.3 pointing directions vertically are with it azimuth dimension on same plane for antenna pitching dimension among the figure.

Fig. 3 is a feed layer microstrip feed line distribution map.The microstrip feed line of feed layer is by distributingpoint 7, firstorder power splitter 8, and secondlevel power splitter 9,10, serialimpedance matching circuit 12 andtransmission line 13 are formed.The semi-flexible cable of distributingpoint 7 weld diameter 2.2mm, energy is distributed to secondlevel power splitter 9 and 10 and make 9 and 10 phase places opposite through firstorder power splitter 8, pass through at last serial impedance matchingcircuit 12 with energy distribution to each radiating element.

Numbering 3 pointing directions vertically are with it azimuth dimension on same plane for antenna pitching dimension among Fig. 3.Microstrip feed line is a serial feed in the feeding classification of azimuth dimension, and the size of 1/4 serial impedance matchingline 12 through regulating each joint realizes the distribution of amplitude, wherein arranges azimuth dimension near two of top edge and lower limb and pitching fibrillar center feeder line distributes with axial symmetry; This two rows feeder line feed is in the opposite direction; The feed of middle row's feeder line the right and left is in the opposite direction, in the pitching dimension, realizes amplitude distribution through regulatingpower splitter 8,9 and 10;Power splitter 8 is through not isometric asymmetric double port network andpower splitter 9; 10 cascades realizepower splitter 9 and 10 180 ° of phasic differences mutually, thus the phase difference that feeder line produced of collocation structure symmetrical distribution.

Fig. 4 is radiating layer, feed layer and reflecting plate assembly sketch map.Shown in the figure, the antenna separation structure is three layers, is respectively radiating layer 11,feed layer 15 and reflecting plate 17.Feed layer 15 is between radiating layer 11 and reflecting plate 17, and every interlamellar spacing is a quarter-wave.The material of radiating layer 11 is chosen as the epoxy resin bonded fiber (single face covers copper thickness 0.035mm) of the thick dielectric constant 4.3 of 1mm; The polytetrafluoroethylene of the thick dielectric constant 2.65 offeed layer 15 material selection 1mm (all thick 0.035mm of copper is covered on the two sides), reflecting plate 17 is smooth no burr metallicplate.Radiation patch 1 dress is affixed on the inner surface of radiating layer 11.Radiating layer 11 also possesses the function of radome simultaneously.Ground plane 14 and feeder line face 16 lay respectively at the upper and lower surface of feed layer 15.Reflecting surface 17 is inner surfaces of antenna housing, andsupport column 19 supports feed layer 15.SMA connector 18 is fixed on reflector 17 outer surfaces, and thesemi-flexible cable 20 that is attached thereto passes viahole 4 around to via hole 5 (in the space, avoiding radiating element), and the cable inner core is soldered to solder joint 7 places.Entire antenna all is in except that connector 18 among the airtight housing.

Theoretical according to Pattern Synthesis, consider the practical structures size, beamwidth is that 15 ° of radiation beam with 30 ° of pitching dimensions of azimuth dimension can realize that unit interval is 48mm * 50mm through 6 * 3 microstrip array.According to the micro strip theory of radiation, be that 4.3 epoxy resin bonded fiber is that the radiation patch of substrate is of a size of 26.4mm * 24mm for the 1mm dielectric constant through calculate adopting thickness.Adopting thickness is that 2.65 polytetrafluoroethylene is that the width of 50 ohm of serial impedance matching lines of substrate is 2.75mm for the 1mm dielectric constant.

In frequency band, be symmetrical distribution through the actual measurement directional diagram, wherein shown in Figure 5 is the pitching dimension directional diagram of a certain frequency.Shown in Figure 6 is the azimuth dimension directional diagram of a certain frequency.Pitching wave beam and orientation wave beam are symmetrical in the antenna array normal respectively, and beamwidth, actual measurement gain meet design requirement.

The invention provides a kind of wave beam symmetrical antenna execution mode in sum, provided the practical implementation way and accompanying drawing is illustrated to the method.Survey the feasibility and the correctness of the feed design of also having verified this uniqueness through concrete emulation experiment and test exemplar.

Claims (5)

1. the little band flat plate array antenna of multilayer of wave beam symmetry; It is characterized in that: this antenna structure is three layers; Form by radiating layer (11), feed layer (15) and reflecting plate (17), the radiation patch that on the inner surface of radiating layer, is symmetrically distributed (1), the radiation patch array is 3*6 totally 18 unit; Said feed layer (15) is positioned between radiating layer (11) and the reflecting plate (17), and every interlamellar spacing is a quarter-wave, and feed layer is ground plane (14) towards the one side of radiating layer; One side towards reflecting plate (17) is microstrip feed line face (16), on ground plane (14), offers the 3*6 coupling slit (6) of totally 18 H shapes, arranges microstrip feed line at feeder line face (16); The microstrip feed line network is by distributing point (7), first order power splitter (8), second level power splitter (9; 10), serial impedance matching circuit (12) and transmission line (13) are formed, distributing point (7) welding semi-flexible cable (20); Energy is distributed to second level power splitter (9,10) and is made (9) opposite with (10) phase place through first order power splitter (8), passes through serial impedance matching circuit (13) at last and gives each radiating element with energy distribution; Said reflecting plate (17) is a metallic plate; Constitute the inner surface of antenna housing, said radiating layer (11) possesses the function of radome simultaneously, and entire antenna is in except that a connector among the airtight housing entirely.

2. the little band flat plate array antenna of multilayer of a kind of wave beam symmetry according to claim 1; It is characterized in that: symmetric form is adopted in the feed layer design; Reduce the influence of feed transmission line array directional diagram; Constitute the beam pattern of symmetry, the center of gravity of the radiation patch (1) of on the geometric center of the radiating slot (6) that adheres on the ground plane (14) and radiating layer, adhering to overlaps; Make the microstrip feed line energy in the feeder line layer be coupled to radiation patch and then radiate, eliminated the coupling influence between feeder line self radiation and the radiating element through the coupling slit.

3. the little band flat plate array antenna of multilayer of a kind of wave beam symmetry according to claim 1; It is characterized in that: the feeding classification at microstrip feed line face (16) azimuth dimension feeder line is a serial feed, and the size of 1/4 impedance matching line (11) through regulating each joint realizes the distribution of amplitude, wherein arranges azimuth dimension near two of top edge and lower limb and pitching fibrillar center feeder line distributes with axial symmetry; This two rows feeder line feed is in the opposite direction; The feed of middle row's feeder line the right and left is in the opposite direction, in the pitching dimension, realizes amplitude distribution through adjusting power splitter (8), (9) with (10); Power splitter (8) is through not isometric asymmetric double port network and power splitter (9; 10) cascade realizes power splitter (9) and (10) 180 ° of phasic differences mutually, thus the phase difference that feeder line produced of collocation structure symmetrical distribution.

4. the little band flat plate array antenna of multilayer of a kind of wave beam symmetry according to claim 1; It is characterized in that on microstrip feed line face (16); Realize that through 6 * 3 microstrip array beamwidth is that 30 ° radiation beam is tieed up in 15 ° of azimuth dimension and pitching, each microstrip line array element spacing is 48mm * 50mm.

5. the little band flat plate array antenna of multilayer of a kind of wave beam symmetry according to claim 1; It is characterized in that: said radiating layer (11) material is chosen as that 1mm is thick, the single face of dielectric constant 4.3 covers copper ring oxygen glass-cloth board; Feed layer (15) material selection 1mm covers the copper polytetrafluoroethylene in two sides thick, dielectric constant 2.65; To be that 0.035mm is thick attach copper to the material of radiation patch (1); Be of a size of 26.4mm * 24mm, to be that 0.035mm is thick attach copper to the material of the impedance matching line (13) on the microstrip feed line face (16), and its width is 2.75mm.

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