BACKGROUND OF THE INVENTION Corner antennas, sometimes referred to as the corner-mirror antennas, are rather widely employed for operation in the range of microwaves and meter-range waves. The design of these in the most simplified form includes two flat plates forming a mirror (reflector) with a radiator located between them. The radiator is usually embodied as a single dipole or a linear dipole array. The axis of the radiator is usually situated in the bisector plane of the antenna. Provided proper selection of the reflector angle and the distance from the dipole axis to the angle vertex, it is possible to ensure favorable combining of the field of the wave reflected from the reflector with that of the wave generated immediately by the dipole. In case of symmetric location of the radiator with respect to the reflector plates and relatively small size of the reflector, the maximum emission is generated predominantly in the direction of the angle bisector. The reflector height is usually selected slightly exceeding the dipole length, the width of each of the plates being not less than the wavelength (cf, e. g., the monograph: G. Z. Eisenberg, V. G. Yampolsky, O. N. Tereshin,"Microwave antennas", Moscow,"Svyaz", 1977, v. 2, p.

122-135) [1]. Employment of the corner antenna is not limited to a single component.

Combination of a multitude of the above-mentioned corner antennas enables creation of a compact antenna system implementing the multi-beam mode of emission/receiving of radio-waves, which is very promising for using in the cellular radio communication purposes (cf., e. g., EP 0624919 Al, NTT MOBILE COMMUNICATIONS NETWORK INC, H01 Q 25/00,17.11.1994) [2].

A number of inventions relate to shaping of the reflector otherwise than planar, which provides for the preset directivity of the antenna. Thus, for example, in the antenna according to the patent US 3803622,343/836,09. 04.1974 [3], the 90'reflector. is embodied as an array of parallel rods and possesses symmetric bends directed outwards at the angle of 10° of 0.23 , width, X being the wavelength of electromagnetic oscillations, the length of the reflectors themselves in the direction of emission constituting 0.21 ?,, and

the dipole being located at the distance of 0.12 X from the edge. In the antenna according to the patent DE 1211499, SIEMENS..., H01Q, 30.11.1967 [4], presented is the antenna comprising a broadband radiator and the complex-shaped reflector possessing the reflector components installed at various angles. Also presented there are nomographs for selection of the distance from the edge, and of dimensions and angles of reflectors to be installed.

More complicated designs of the corner antennas comprise improvements in reflector designs. For example, in the reference JP 11205030 A, Ueda Japan Radio Co Ltd, HOlQ 15/18,30.07.1999 [5], the antenna is presented comprising a corner reflector consisting of two conducting plates located at the specified aperture angle and of an exciting component installed at the specified distance from the plates. Flat conductors are fixed to the plates in the direction of the aperture located with a gap with respect to edges of said plates. The problem of obtaining of a high antenna gain without increasing of the physical area of the corner reflector components is thereby solved. According to [5], this solution is useful for reduction of the structure wind loading.

Said references [1]- [5] disclose the information on corner antennas possessing the angle between reflecting plates in the direction of the aperture (p < a. Described also is the antenna with the angle between reflecting plates (p > a, which enables covering of essentially larger sector of emission. For example, described in the patent US 2720590, Nail et al., 343-818,11.10.1955 [6] wherein said angle zp constitutes 180 to 330°. Width of reflector plates is 1 to 2 X, height along the corner edge 5/8 to 1 X, dipole offset being 1/8 to 3/8 B.

The above-mentioned designs of corner antennas can provide, depending on parameters being employed, forming of various types of polar patterns. These comprise "sector"type polar patterns featured by relative uniformity of the antenna gain in the specified azimuth range with the falloff beyond this sector. Sector-type antennas are very useful for establishing of uniform coverage areas, for example, for the mobile communication purposes, as well as in a number of other applications. Polar patterns of another type, so-called pencil-beam patterns, can also be formed with corner antennas for a specified sector of azimuthal angles.

The purpose of the claimed invention is improvement of the antenna design for the sake of enhancing corner antenna operation efficiency in forming both sector and pencil- beam polar patterns in a wide range of azimuthal angles.

SUMMARY OF THE INVENTION According to the present invention, a corner antenna comprises a corner reflector formed by two rectangular conducting plates jointed at an angle and performing the function of main reflectors, a radiator located above the surface of said main reflectors, additional rectangular conducting plates performing the function of additional reflectors, wherein each said additional rectangular conducting plate is located at an angle to said rectangular conducting plate of main reflectors and jointed with the latter, the joint edges of said plates of main and additional reflector being parallel.

The corner antenna can be characterized by the fact that the value of the angle (p at which rectangular conducting plates performing the function of main reflectors satisfies the condition: 0 < (p < ? E.

The corner antenna can be also characterized by the fact that the angle (p at which rectangular conducting plates performing the function of main reflectors satisfies the condition: a < (p < 2 ? E.

The corner antenna can be also characterized by the fact that the angles at which each of said additional reflector plates is located satisfy the conditions: 0 < a < (PI ; 0 < ß < #2; #1 + #2 = #, #1 and cpz being angles between each of the main reflector and the plane passing through the radiator device and the joint line of main reflectors; and a and being angles between each of the additional reflectors and the plane passing through the radiator device and the joint line of main reflectors.

The corner antenna can be characterized by the fact that said radiator device is located symmetrically with respect to the joint edge of said conducting plates of main reflectors at the distance s satisfying the condition 5/8 k > s > 1/8 X, k being the wavelength of electromagnetic oscillations in the medium filling the cavity of the corner reflector.

The corner antenna can be further characterized by the fact that said radiator device is embodied as a linear array of radiators installed parallel with respect to the joint edge of main reflectors.

The corner antenna can be further characterized by the fact that each of radiators is embodied as an electric dipole.

The corner antenna can be further characterized by the fact that said conducting plates are embodied out of metal plates.

The corner antenna can be further characterized by the fact that the corner reflector is embodied out of a single metal sheet.

The corner antenna can be also characterized by the fact that said corner reflector is embodied out of polymer materials and the conducting plates are formed through laminating of the reflector cavity with metal.

The corner antenna can be also characterized by the fact that the end surfaces of said corner reflector are equipped with covers jointed to said corner reflector enabling attaching to the latter ones the components for antenna mounting and the means for connecting to antenna feeder tract.

The corner antenna can be further characterized by the fact that said covers are embodied out of conducting material.

The corner antenna can be further characterized by the fact that the said reflector cavity is filled with a dielectric material.

The corner antenna can be further characterized by the fact that the aperture of the corner reflector is covered with a radome made out of radio transparent material.

BRIEF DESCRIPTION OF THE INVENTION The invention is disclosed in the following detailed description and accompanying drawings, wherein: FIG. 1 presents the cross-section of the corner antenna in compliance with the invention in the horizontal plane for the version 0 < p < z ; FIG. 2 presents the cross-section of the corner antenna in compliance with the invention in the horizontal plane for the version X < T < 2X ; FIG. 3 is the general view of the corner antenna for the version presented in FIG. 1 ; FIG. 4 is the general view of the corner antenna for the version presented in FIG. 2; FIG. 5 is the comparison of the dependence of gain vs azimuthal angle 6 for an ordinary corner antenna [1] (curve 1) and the claimed antenna design for the case 0 < (p < s (curve 2); FIG. 6 is the comparison of the dependence of gain vs azimuthal angle 8 for the claimed antenna design for the case 7s < (p < 2a, (curve 1), for the case 0 < (p < x, (curve 2), and for the case 7s < (p < 2 ? E, but without additional reflectors (curve 3); FIG. 7 presents an example of the embodiment of the reflector integrated with the radome made out of a profiled tube.

DETAILED DESCRIPTION OF THE INVENTION Embodiment of the corner antenna according to the present invention shall be preceded by selection of parameters basing on particular application requirements. The working frequency band (for the described example of the antenna embodiment, this constitutes 1.7... 2.0 GHz) and the maximum aperture size (A) shall be stipulated. Then the type of the radiator device shall be determined basing on the requirements for orientation of polarization vector of electromagnetic emission. For the described example of the embodiment, the vertical polarization is stipulated, which is provided for by employment of vertical dipoles. The polar pattern for such dipoles in the horizontal plane is uniform.

Then, according to the invention, the parameters of the reflector with the geometry presented in FIG. 1 or FIG. 2 are chosen. These parameters comprise: angles (pi and (p2 at which rectangular conducting plates performing functions of main reflectors are connected; angles a and P at which each of the plates of additional reflectors is located with respect to the plane passing through the radiator device and the joint line of main reflectors; dimensions of additional reflectors a, b and radiator offset (distances Si, s2 between the corner apex and radiator). For symmetrical embodiment of the reflector and, respectively, forming of symmetrical polar pattern of the corner antenna, the following conditions must hold: (pi = (p2, a = ß, a = b, si = s2. The impedance of dipoles is adjusted through selection of the dipole length and the distance s in the range satisfying the condition 5/8 k > s > 1/8 X, so that the imaginary part of the input impedance would approach zero with the real part being close to characteristic resistance of the transmission line exciting the dipole. If a power divider is installed between the transmission line and the cable (in case of radiator embodied as an array), then the value of the active part of the input impedance of said divider shall be equal to the value of the characteristic resistance of the cable.

After this, employing methods of computational electrodynamics, for example, methods of integral equations (cf. A. G. Davydov, Yu. V. Piimenov, Software complex EDEM3D for investigation of electrodynamical characteristics of ideally-conducting three-dimensional objects// « 3ieKTpoRHHaMHKa CBI H KBLI (Electrodynamics of UHV and VHF) », 1999, v. 7, issue 2, page 24-26) [7], the polar pattern of the antenna in the horizontal plane shall be calculated. Then the geometrical parameters of the antenna are selected with the purpose of obtaining the polar pattern of the stipulated shape, e. g. with

the maximum possible squareness (meander) or of pencil-beam shape, employing the multidimensional optimization methods (cf., e. g., M. Aoki, Introduction into functional optimization methods.-Moscow,"Nauka", 1976) [8].

FIG. 1 presents in detail the cross-section of the claimed corner antenna for the version 0 < (p < 7C. Reflecting conducting plates 10,12 performing functions of the main reflectors are jointed along edge 14 and form a corner reflector 16 with the angle (p = (pi + #2. The radiators 18 are located at distances si, s2 from the reflecting plates 10,12 and at the distance s from the edge 14. In the special case of radiators 18 located in the bisector plane 20 of the corner reflector (q>l = (P2), Si = S2 = S ° sin (q)/2).

Connected to the conducting plates 10,12 along edges 22,24 are additional conducting reflecting plates 26,28 with dimensions a, b. Edges of the plates 22,24 are parallel to the edge 14. Additional reflectors 26,28 are located at angles a and ß to the plane passing through the radiator device 18 and the joint line 14 of main reflectors.

Accordingly, for the version presented in FIG. 1, the following conditions hold: 0 < # < #, 0 < α < #1, and 0 < ß < #2.

FIG. 2 presents in detail the cross-section of the claimed corner antenna for another version 7t < T < 2#.

The corner antenna comprises reflecting conducting plates 110,112 jointed along edge 114 of parallel facets. Plates 110 and 112 performing functions of the main reflectors form a corner reflector 116 with the angle # = (pi + cpa. The radiators 118 of the radiator device are located at distances si, S2 from the reflecting plates 110,112 and at the distance s from the edge 114 (s1 = s e sin (pi, S2= s * sin #2).

Connected to the conducting plates 110,112 at edges 122,124 are additional conducting reflecting plates 126,128 with dimensions a, b. Edges of the plates 122,124 are parallel to the edge 114, and they form additional reflectors located at angles a and with respect to plane 120. Values of said angles satisfy the conditions: 0 < oc < (pi and 0 < ß < (p2 If the antenna is to have a symmetrical polar pattern, then values of the angles and dimensions are selected from the condition: (pI = (p2s a =, a = b, si = s2.

FIG. 3 presents the general view of the antenna for the version presented in FIG. 1.

Installed and attached at the end surfaces of the corner reflector 16 are covers 30,32 constituting mounting bases for radiators 18 and electric connector 34 intended for

connecting the radiator device to the antenna feeder tract. The covers can be embodied out of a conducting material. The corner reflector can be equipped with means providing fastening thereto components for antenna mounting and fixing on an object (not shown in the figure).

Radiators 18 of the radiator device are embodied as a linear radiator array 40 located in parallel to the edge 14. Each of the radiators 40 is embodied as an electric dipole. The design of such radiators 40 is known, and in the present invention the radiators are employed with the known purpose. The height of the antenna in the vertical plane is L.

As shown in FIG. 3, the antenna has aperture size"A"and overall length in the direction of emission"w".

FIG. 4 presents the general view of the antenna for the version presented in FIG. 2.

Installed and attached at the end surfaces of the corner reflector 116 are covers 130,132 constituting mounting bases for radiators 118. Installed on the cover 132 is electric connector 134 intended for connecting the radiator device to the antenna feeder tract. The covers 130,132 can be embodied out of a conducting material.

Radiator device 118 is embodied as a linear radiator array 140 located in parallel to the edge 114. Each of the radiators 140 is embodied as an electric dipole. The design of such radiators 40 is known, and in the present invention the radiators are employed with the known purpose. The height of the antenna in the vertical plane is L. The antenna has aperture size A and overall length in the direction of emission w.

As it was mentioned above, the present invention relates to improvement of the antenna design with the purpose of enhancing of the factor of reflector area employment.

Achievement of the positive result is shown below, on examples of improved efficiency of the corner antenna in forming of both sector and pencil-beam polar patterns in a wide range of azimuthal angles. The conception of synthesis of the antenna corner reflector according to the invention enables, provided proper selection of the device geometrical parameters in compliance with methods [7,8], synthesizing of sector-type polar patterns, which is illustrated in the following graphs.

FIG. 5 presents dependencies of gain vs. azimuthal angle A for an ordinary corner antenna [1] (curve 1) and the antenna of the claimed design for the version presented in FIG. 1 (curve 2) at the frequency 1.92 GHz at (p = (pi + (p2, provided (pi = (p2. The corner antenna possesses the rectangular (meander) polar pattern characteristics in the sector of 30°. The values of the respective geometrical parameters are summarized in the Table 1. Presented in the same table are the geometrical parameters of the example of the known antenna [1], which served as a reference for testing.

Table 1. Parameters q), a, ß A, s, a, b w, L, Number of deg deg mm mm mm mm mm radiators Antenna ace. to 162 35 316 35 30 46 800 8 FIG. 1 Traditional antenna 60-160 55-138 800 8 fit

Both antenna gains are normalized by the gain value of the claimed antenna a o = O. One can see that the claimed antenna design provides within the 60-degree sector a more uniform level of emitted power (non-uniformity 1 dB) than the known corner antenna (non-uniformity 3 dB). With this, the emission level of the claimed antenna for angles 9 > 90° is less than that of the known antenna, the minimum gain value within the sector 30° being approximately 1dB higher.

Examination of the antenna have demonstrated the antenna gain in the specified frequency range 1.8... 2.0 GHz to be 14.1... 14.3 dB, which is close to the expected value. The standing wave ratio (WSR) was less than 1.5 in the frequency range 1.8... 2.0 GHz.

FIG. 6 demonstrates comparison of gains vs azimuthal angle 8 for the version presented in FIG. 2 (n < (p < 2#) (curve 1), for the version presented in FIG. 1 (0 < (p < zu (curve 2) and for the design according to the version 7c < cp < 27r, but without employing additional reflectors 126,128 (curve 3). Considered is the case of (pi p2 a a = b, si = s2. Design parameters of antennas are shown in Table 2.

The presented data demonstrate variation of the antenna (curve 1) gain factor in the range i 40° at the frequency 1.8 GHz provided the same aperture (A) to be not exceeding 0.2 dB. At the same time, for the antenna (curve 2) and the antenna without additional reflectors (curve 3) this value reaches 0.4 dB. Gain factor of the claimed antenna constitutes ca. 14 dB, which is rather close to the expected value.

Table 2. Para- (P = a, ß A, Si, a, b, w, L, Number Gain, meters q) i+ (p2, deg mm mm mm mm mm of dB deg radiators Curve 217 35 264 36,3 61,8 68,5 800 8 14,0~0, 1 1 Curve 148 35 264 36,3 60,0 75,2 800 8 14,00,2 2 Curve 217-264 36,3-80,3 800 8 13,50,2 3

Apart from the above, as the examples of the invention embodiments, beam corner antennas have been synthesized possessing pencil-beam polar pattern. Values of respective geometric parameters and gain factors of corner antennas for versions presented in FIG. 1,2 with main lobe width ca. 32° (at minus 3 dB level) at the operating frequency 1.8 GHz are summarized in Table 3. For the sake of comparison, presented in the same table are the respective values for a traditional corner antenna (0 < # < 7C) without additional reflector, denoted as items 26,28 at FIG. 1.

Table 3. Antenna (p, a, P, A, s, a, b, w, L, Number Gain, dB parameters deg deg mm mm mm mm mm of radiators Antenna 140,3 20,3 264 36,3 113 170,4 800 8 19, 2 FIG. 1 Antenna 220 43,2 264 36,3 113 104,8 800 8 19, 7 FIG. 2 Traditional antenna 94,6-264 36,3-143,2 800 8 18,3 [1

Table 3 shows both claimed version of antenna to possess higher efficiency, as at the same value of the aperture (A) they provide higher gain. Besides, in the second version as compared to the first one, lower longitudinal dimensions (w) are provided for.

The data obtained testify to the claimed antenna both providing high efficiency and low gain variation of sector polar patterns and high gain pencil-beam polar patterns.

The corner reflector of the claimed antenna can be embodied using various technologies, e. g. non-cutting shaping, punching, bending all respective components of the structure simultaneously (plates of main and additional reflectors, end covers) out of metal

sheets, preferably out of aluminum alloys. The same components or their constituting parts can be shaped separately with subsequent assembling. Besides, the reflector can be embodied out of plastic by means of compacting with subsequent coating (laminating) of internal surfaces with metal foil. The reflector cavity together with radiators can be filled with foamed polystyrene or another similar material belonging to the group of non-polar solid dielectrics and can contain other non-metal protective components preventing from penetration of atmospheric precipitation. For example, the corner reflector aperture can be covered with radome fabricated out of radio-transparent material (not shown).

A distinct decision is embodiment of the reflector out of a dielectric elongated profile 50 of a tubular shape demonstrated in FIG. 7. In the course of extrusion shaping, the profile can be set having any shape, basing not only on the required parameters of the corner reflector, viz. dimensions and slopes of planes, but as well on those of radome 52 and mounting components (not shown in the figure). However, the basic advantage in this case would be the fact that a separate protection component, the radome, would not be necessary in the reflector aperture, which provides for the water-tightness along the side surfaces.

INDUSTRIAL APPLICABILITY As follows from the above description, reflector and other components of corner antenna can be manufactured using traditional technologies, means, and materials. The radiators can be embodied through various methods. In particular, the technology of printed radiator manufacturing by means of lithography, i. e. etching of metallized dielectric material, can be employed, as well as other methods. Similar methods can be used for manufacturing of electric matching components. The disclosed information testifies to the industrial applicability of the claimed invention.