|Title of Invention||
"LINEAR HIGH FREQUENCY ANTENNA."
|Abstract||The inventive linear high-frequency antenna consists of a multichannel frequency divider (2), a consecutive system of radiators and a connection element of radiators provided with the outputs of the multichannel frequency divider (2). Said multichannel frequency divider is embodied on a non-symmetrical stripline and is arranged inside a rectangular tube (1) on the large wall thereof. A periodical system is embodied in the form of windows (10) on the narrow wall of the rectangular tube (1). The connection elements are embodied in the form of capacitive (11) or inductive vibrators (12) remote from the other narrow wall of the rectangular tube (1) at a distance equal to quarter of the mean wavelength. The use of the invention makes it possible to reduce the size, simplify the structural design and to improve the electrical parameters of the antenna.|
|Full Text||LINEAR HIGH-FREQUENCY ANTENNA
DESCRIPTION OF THE INVENTION Field of the invention
The invention relates to UHF radio engineering and can be used in radiolocation for development of linear antennas as well as flat arrays.
Background of the invention
Widely used in radiolocation slotted-guide antenna (G.Z. Izenberg and others "VHP antennas", part 2, pp. 177-205, Publishing house "Communication", M., 1997; Patents of Russia SU 1746444, RU 2206157) is a rectangular waveguide with periodically distributed slots in a narrow or a large wall of the waveguide. Slotted-guide antennas with inclined slots in a narrow wall of the waveguide are simple such a construction, but have a number of drawbacks: band limitedness (10%); presence of resonances caused by dispersive characteristics of a waveguide; a law coefficient of efficiency (80-90%) and a considerable level of side lobes in antenna pattern (especially when there is a small number of slots) conditioned by a maximum meaning of coupling coefficients at a level not more than minus 10 dB and conditioned by an opposite angle of inclination of the neighboring slots; undesirable underscanning of the main beam along the waveguide during work in a frequency band. Besides the using slotted-guide antennas in Dissymmetrical wave band is limited by increasing characteristics of mass and overall dimensions, because in a waveguide its cross dimensions are proportional to a wavelength.
When the double slots are use (Patent of the USA US 3740751) that such characteristics as increasing of broadbandness and coefficient of efficiency are improve. But this action does not eliminate fundamental drawbacks, caused by series connection and inclination of the slots.
Reactive elements (inductive vibrators, for example) are usually use for excitation of straight slots, which made on a narrow wall of the waveguide ("VHP Antennas", p. 181). This action allows to eliminate the drawbacks connected with inclination of slots, but makes some
The construction of printed-stripline antennas has more important qualities (Patent of Russia SU 1835974; V.V. Demidov and others "Printed-stripline vibrator phased arrays of L and S-frequency bands", Publishing house "Antennas", edition 9 (55), p. 3-8, 2001.). Said antenna usually consists a printed-stripline power divider with cophased outputs loaded on printed-stripline vibrators.
These antennas have a number of drawbacks: complicated technological fitting out, increasing level of input losses and a relatively low level of throughput power.
Summary of the invention
Proposed invention decides a task connected with widening of technical means arsenal of the said purpose and with improving of exploitation characteristics.
The use of the invention makes it possible to reduce the size, simplify the structural design and to improve electrical parameters of the antenna.
The essence of the proposed invention is embodying of a frequency divider on a non-symmetrical stripline ("Reference book for calculation and designing of SHF devices", edited by I.V. Volman, M, Publishing house "Radio and Communication", 1982) and arranging it inside of a rectangular tube on the large wall of thereof with a periodical system of radiators embodied in the form of emitting windows on the narrow wall of the rectangular tube. The connecting elements of the radars are embodied in the form of capacitive or inductive vibrators remote from the other narrow wall of the rectangular tube at a distance equal to 0,25 Λ0 (where Λ0 - average wavelength).
Brief description of the invention
At the Fig. 1-2 is described the structural design of one of possible variants of a linear antenna with multichannel frequency divider of a parallel type, T-couplers and vibrators of a capacitive type. Said structural design of the linear antenna can be easily realized in a long wave part of Dissymmetrical wave band.
The variant of the linear antenna with convolute multichannel frequency divider and vibrators of an inductive type is more suitable for work in a short wave part of Dissymmetrical and Centimetric wave bands and it is described at Fig. 3, 4.
The variant of the linear antenna with multichannel frequency divider arranged as a consecutive system and with using of directional couplers or T-couplers is suitable for work in a wide wave band, including in a Metric wave band, and it is described at Fig. 5, 6.
Description of the preferred embodiment
A proposed invention (see Fig. 1, 2) consists of a rectangular tube 1 (it need not be waveguide), multichannel frequency divider 2 is embodied on a non-symmetrical stripline with dielectric substrate 3 (fabricated from the foam plastic, for example) and is arranged inside the rectangular tube 1 on the large wall thereof.
The conductors of the multichannel frequency divider 2 are produced from the light sheet (1-2 mm), for example, hard aluminum alloy, that provides to reduse a level of losses and to increase a level of throughput power in comparing with printed conductors. Economical expediency is evident, because current computer technologies permit to produce a few complicated items having low cost.
An entry coaxial connector 4 is situated from the side of a narrow wall of the rectangular tube and fastened on this wall by the boss 5.
For receiving differential channel at the linear antenna a bridge device 6 of "hybrid ring" type is connected to an input of the multichannel frequency divider 2. A differential arm 7 of the bridge device 6 is leaded out through the large wall of the rectangular tube 1.
Widely used in practice irregular distribution of power along the linear antenna at said construction of the multichannel frequency divider is realized by the wave impedance drops of output arms of the T-couplers 8, which characterized by the width of conductors W1 and W2.
For reducing cross dimensions of the linear antenna, that is important for working in a Dissymmetrical wave band, the main transmission line
impedance of the multichannel frequency divider which characterized by the width W0 is selected equal to 100 ohms. A step junction 9 is used for matching the multichannel frequency divider with standard 50-ohms input 4. A periodical system of radiators is the windows 10 slotted in the narrow wall of the rectangular tube 1. Electric coupling between emitting widows 10 and outputs of the multichannel frequency divider 2 is effected with a system of capacitive vibrators 11 removed from the narrow wall of the rectangular tube at a distance L approximately equal to 0,25 Λ0 (Λ0 - average wave length). A distance d between emitting widows 10 and between neighbor outputs of the multichannel frequency divider and a width C of emitting widow are selected according to condition:
0,5 Λ0 It was experimentally found out that selection of a width C of emitting widow exerted on antenna matching. An optimal dimension of width C is within the limit from 0,5 Λ0 to 0,75 Λ0. An emitting widow height S is not a fundamental importance and can be selected equal to or lesser then a height b of the rectangular tube 1. A width a of the rectangular tube is selected within the limit from 0,25 Λ0 to 0,5 Λ0.
The cross dimensions of the multichannel frequency divider do not depend on a working wavelength and are mainly defined by the non-symmetrical stripline dimensions h and t (see Fig. 2). So mass and overall dimensions of linear antenna are reducing with increasing of a working wavelength.
The variant of linear antenna for working in the more short waves is described by Fig. 3, 4. The necessary condition about removing of vibrators 11 from the narrow wall of the rectangular tube 1 at a distance L approximately equal to
0,25Λ0 is provided by the 180°-turn of output arms of a multichannel frequency divider.
As it is described at Fig.4 (it was experimentally found out) an emitting electric wave vibrator 12 can be inductive, in another words it is connected to a large wall of the rectangular tube 1.
For working of linear antenna in environment an inside cavity of the rectangular tube 1 is filled out by the sealing radioparent dielectric, for example by foam plastic (as it is shown at Fig. 2) or the emitting windows 10 are filled out by the radioparent dielectric 13, for example by fluoroplastic (as it shown at Fig.4).
The Fig.5 describes a construction of linear antenna with the multichannel frequency divider containing a centrally positioned entry coaxial connector 4. Either of the two mirrorly-like situated branches of the multichannel frequency divider 2 is a frequency divider made on base of directional couplers 14 with quarter wave couplings. A coupling coefficient of directional couplers 14 with quarter wave coupling is defined by a gap A between conductors of primary and secondary lines. Directional couplers 14 are separated at a distance K equal to Λ0 and this action provides a phase synchronization for outputs of the multichannel frequency divider. A distance d between neighbor outputs of the multichannel frequency divider is defined by a T-coupler 8 and equal to Λ0. An emitting through the windows 10 is provided by capacitive and inductive vibrators 11 or 12 removed from the narrow wall of the rectangular tube 1 at a distance L approximately equal to 0,25V
The variant of a leaner antenna with a consecutive multichannel frequency divider and used in it T-couplers 8 and 15 only is described at Fig.6. The main dimensions L, d and K of the multichannel frequency divider have the same meanings how it was found out for the previous variant of a linear antenna described at Fig. 5.
A waveguide with section 110 x 55 mm was used for experimental control of the linear antenna working in a 30-centimetric wave band. A four-channel frequency divider was based on strip line with the height h=5 mm and with the thickness of the conductor t=l mm (see Fig. 1, 2). When a wave impedance of coaxial inputs was equal to 50 ohms a voltage standing-wave ratio of linear antenna did not exceed 1,5 in a frequency band from 1,0 to 1,20 GHz.
1. Linear high-frequency antenna consisting of a multichannel frequency divider, a periodical system of radiators and connection elements of radiators with outputs of the multichannel frequency divider (2) embodied on a stripline with dielectric substrate (3) and arranged inside a rectangular tube (1) characterized in that the multichannel frequency divider (2) is embodied on a nonsymmetrical stripline with dielectric substrate (3) arranged on one of the large walls inside the rectangular tube (1) a width of which is selected ~ 0,3 A0,(where A0 - is an average wavelength), the periodical system of radiators is embodied in the form of emitting windows (10) on one of the narrow walls of the rectangular tube (1), the width of each emitting window (10) is ~ 0,5 A0, and the connection elements are embodied in the form of capacitive (11) and inductive vibrators (12) removed from the other narrow wall of the rectangular tube (1) at a distance equal to 0,25 A0, a distance d between the emitting windows (10) and between neighboring outputs of the multichannel frequency divider (2) is selected according to condition 0,5 Ao
3. The linear antenna as claimed in claim 1. wherein the emitting windows (10) are filled out by the radioparent dielectric (13), for example by fluoroplastic.
|Indian Patent Application Number||4683/DELNP/2006|
|PG Journal Number||28/2009|
|Date of Filing||14-Aug-2006|
|Name of Patentee||FEDERAL STATE UNITARY ENTERPRISE "STATE MOSCOW PLANT "SALYUT"|
|Applicant Address||6 PLEKHANOV STR., MOSCOW 111123, RUSSIA|
|PCT International Classification Number||H01Q 9/06|
|PCT International Application Number||PCT/RU2005/000243|
|PCT International Filing date||2005-05-05|