Patent Grant
9590315
This application claims the benefit under 35 U.S.C. §119(a) of a Russian patent application filed on Jul. 15, 2014 in the Russian Patent Office and assigned Serial number 2014129187, and of a Korean patent application filed on Jun. 25, 2015 in the Korean Intellectual Property Office and assigned Serial number 10-2015-0090368, the entire disclosure of each of which is hereby incorporated by reference.
The present disclosure relates to antenna technology. More particularly, the present disclosure relates to a planar linear phase array antenna with enhanced beam scanning.
In the technological field of scanning antennas, increasing a scan angle is a very practical issue in order to improve the efficiency of a system. The scan angle of an antenna array of the related art is usually restricted to ±45 degrees without a considerable gain loss. However, special facilities are required for realization of the scan angle enhanced up to 70 degrees, especially for mobile devices, because optimal traffic varies within wide limits.
A conformal antenna array (cylindrical), Luneburg lens antennas, switchable axisymmetric antennas are applied to increase the scan angle. These types of antennas allow acquisition of a scan angle of ±90 and more. However, there are some drawbacks inherent for these antenna types.
The antenna arrays of the related art are suitable for obtaining extended beam scanning by special structures installed in front of the arrays. These structures cause the additional front wave deflection. However, these structures are used usually for large arrays having wide sides.
Therefore, all of the afore-mentioned technologies are not suitable for designing very compact antenna devices.
There are some known solutions directed to creating a very compact phase antenna array that provides beam scanning over a possible wide range.
Referring to
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Further, the previously known antennas that provide beam scanning have such drawbacks as high complexity in production and assembly, the presence of complicated switching and feeding circuits, and partial use of radiating elements.
Therefore, a need exists for a planar linear phase array antenna with enhanced beam scanning.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.
Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide an extremely compact phase antenna array providing beam scanning at an angle equal to or greater than ±75 degrees.
In accordance with an aspect of the present disclosure, a planar phase array antenna is provided. The planar phase array antenna includes a planar waveguide formed by a top ground and a bottom ground with a dielectric layer between the top ground and the bottom ground, a phase array, including radiators, configured to form an electromagnetic wave front inside the planar waveguide, at least one back side reflecting structure located behind the phase array, and at least one deflecting structure, implemented in the dielectric layer, configured to deflect the electromagnetic wave front inside the planar waveguide, wherein a permittivity value of the at least one deflecting structure is not equal to a permittivity value of the dielectric layer of the planar waveguide.
According to some embodiments of the present disclosure, the top ground may be shorter than the bottom ground.
According to some embodiments of the present disclosure, the planar phase array antenna may further include a transformer configured to transform a vertical polarized wave to a horizontal polarized spatial wave formed along an outer boundary of the planar waveguide.
According to some embodiments of the present disclosure, a whole antenna may have a planar form and may be produced based on printed circuit board (PCB) technology but is not limited to. These features are very attractive for implementation of an antenna within compact devices for mobile scenario, such as hand-held phones, tablet person computers (PCs), and the like.
In comparison with analogues antenna of the related art, the antenna according to the embodiments of the present disclosure does not have any variable active lumped elements for beam scanning. A main feature of this antenna is application of a special deflecting structure represented by a metamaterial medium for obtaining enhanced beam scanning. The medium presents a special form area inside the PCB structure. This metamaterial area is formed so as to realize an additional delay of a wave front at the antenna array periphery. This phase delay causes additional deflection of the wave front. As a delaying metamaterial, a metalized holes (via) inside the PCB is used. Due to different heights of the holes (via) into a padding area, the irregular delaying of the wave front is obtained. As a result, the beam scanning of a single phase array is enhanced from ±55 degrees to ±75 degrees.
The main difference of the present disclosure from the prototype is the realization of a deflecting area inside a very thin planar structure, for example, the PCB structure. Therefore, the described device may be designed as an element of devices for a portable scenario (hand-held phones, tablet PCs, and the like). The deflecting system of the prototype represents a spherical, not compact, form.
According to an embodiment of the present disclosure, the antenna represents a linear phase array. However, other possible phase array structures could be used.
Any suitable types of radiators may be used as elements of the array. Monopoles are preferred because they provide best matching and possibility of PCB realization. Loop radiators may also be advantageously used.
The number of radiators may be different and it is restricted only by design requirements.
Elements of the array located into the medium of the solid dielectric layer (the PCB substrate) between a couple of horizontal parallel ground planes. The combination of ground planes and the solid dielectric form a planar waveguide. The common reflector is disposed back from a line of radiators at a distance approximately ¼ wave length into the solid dielectric for best matching and optimal beamforming. The array of radiators in combination with a reflector forms a unidirectional plane wave propagated inside the planar waveguide. The planar waveguide is formed by a couple of parallel ground planes and the dielectric substrate between the ground planes. The optimal form of the outer boundary of the planar waveguide is a semicircle, but any symmetrical curves are also possible (i.e., ellipse, parabolic, and the like), and radiated elements are situated along the diameter. It is possible to steer the wave front direction in a relatively normal position by phase control at the radiators (for example, vertical monopoles). The area of the deflecting structure is disposed between the radiation array and the outer boundary of the planar waveguide. The deflecting structure includes one or more sub-deflectors. The first sub-deflector is a major and located closely to the outer boundary of the planar waveguide. In addition, the second sub-deflector may be used which is auxiliary and located between the phase array and the first sub-deflector.
According to one of embodiments of the present disclosure, provided into the solid dielectric, the profile of the first sub-deflector area is shaped into a horseshoe convex to the periphery of the antenna. The thickness of the first sub-deflector area is minimal in the center and smoothly increases towards sides. The deflecting structure itself could represent an artificial dielectric with various permittivity values. First sub-deflector permittivity is more than the solid dielectric's one, and second sub-deflector permittivity is less than the solid dielectric's one. The artificial dielectric of the first sub-deflector causes complementary delay of the wave front and furthermore the delay is not constant for different parts of the wave front because the thickness of the first sub-deflector varies too. Accordingly, when the front of a wave is deflected, the side of the wave front located closely to the array will experience more delay due to the larger thickness of the artificial dielectric. As a result, the scanning angle is extended.
In order to increase the deflection efficiency, the second sub-deflector could represent the artificial dielectric having a permittivity less than a permittivity of the dielectric layer. This area is near the inner side of the first deflector and has a profile of a crescent. The thickness of the second sub-deflector area is maximal in the center and smoothly decreases towards the sides. The process of impact on the wave front is the inverse of the described above one. The part of the wave front, which is more distant from the radiators' array passes through a thicker region of the second area than the opposite one. Due to the lower permittivity of the second area, this part of the wave front gets additional acceleration and this effect causes the complementary deflection of the whole front. The area of the first sub-deflector is artificial dielectric including tens of metalized holes (via) into the dielectric layer of the planar waveguide (PCB dielectric media). Every metalized holes (via) is the discontinuity into the planar waveguide and distinguished by some impedance due to which the extra phase delay is obtained. At that value of permittivity and phase delay depend on the height of the holes (via). The distance between the holes (via) approximately equals a ¼ wave length into the substrate for realization of maximal transparency of the deflecting structure.
The area of the second sub-deflector is artificial dielectric with a lower permittivity than substrate's one including tens of metalized holes through unmetallized holes (via). Because the holes for this case are filled by air, the effective permittivity of this area may be less than one of a solid dielectric. The value of permittivity is determined by the density and diameter of holes. Passing through this medium the wave undergoes the complementary acceleration regarding to the solid dielectric. Thus, there is a double effect of the additional deflecting of the wave front here, specifically deceleration of one side of the wave front and acceleration of the other side of the wave front. If the bore side direction mode (without scanning) is generated, the sides of the wave front get the similar delay because of the symmetric form of the deflecting structure. However, the wave front is warped due to high speed of wave in the middle part of the antenna, this distortion may be compensated by corresponding phase correction at radiators. Further, the passed through deflecting structure transversal electromagnetic (TEM) wave proceeds to an edge of antenna and is irradiated into space.
Due to the extremely small height of the planar waveguide restricted by the thickness of the PCB, the efficiency of radiation is very low. In such a case, according to an embodiment of the present disclosure, it is proposed to use transformation of the vertical polarization to horizontal one that allows realization of the high radiation efficiency. The vertical polarized wave that has reached the edge of the planar waveguide is distributed to a group of channels through exponent tapers allocated at the edge of the planar waveguide. These tapers represent the extension of the planar waveguide. Every partial wave passed through the exponential taper come in the dipole oriented horizontally. Every arm of the dipole is the continuance of top or bottom ground of the planar waveguide. The effective length of dipoles is sufficient (about ½ wave length). Therefore, the space matching and radiation are very good. In a view of the total directivity increase, the director disposed in front of every dipole.
According to another aspect of the present disclosure, the architecture of the antenna may be simplified in a case of increasing the thickness of the planar waveguide, thereby obviating the need for polarization transforming.
According to another aspect of the present disclosure, the antenna is ended by a smooth edge of the planar waveguide and polarization of radiation is vertical. The top ground is shorter than the bottom ground. The protruding part of the dielectric layer in combination with the bottom ground serves as a matching transformer between the planar wave guide and space.
Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure.
The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
Specifically,
Referring to
The array irradiates a vertical polarized transversal electromagnetic (TEM) wave into the space of the planar waveguide. To provide one-directional propagation, a back side common reflector 5 is located behind the monopoles 1 at a distance of an approximately ¼ wavelength inside the dielectric layer 2. When an exciting phase is same for every monopole 1, the wave front is propagated normally to the array. The direction of propagation takes some deflection provoked by a phase difference between the monopoles 1. In the process of propagation of the wave front from the monopoles 1 to a planar waveguide edge 6, the planar wave passes through an area of a deflecting structure including a first sub-deflector 7a and a second sub-deflector 7b. The planar form of the deflecting structure is partially cylindrical, and the generator of cylinder is perpendicular to the top ground 3 and the bottom ground 4.
Referring to
To purposely enhance the effect of additional deflection, the second sub-deflector 7b is implemented. The sub-deflector 7b is interposed between the first sub-deflector 7a and the monopoles 1. Herein, compared to the first sub-deflector 7b, the area of the second sub-deflector 7b is filled with non-metallic hollow holes 9. The permittivity of the dielectric layer 2 is lower than one of a solid dielectric. The area of the second sub-deflector 7b is near the first sub-deflector 7a, and the profile of this area is the reverse of that of the first sub-deflector 7a. Specifically, the thickness of the planar shape of the area of the second sub-deflector 7b is maximal in a normal direction with respect to the line of the radiators and is smoothly reduced toward the sides. The structure of the second sub-deflector 7b may be regarded actually as an area having a plurality of holes formed into the dielectric layer that forms the planar waveguide.
Referring to
After the deflection structure, the scattered TEM wave reaches the planar waveguide edge 6. However the radiation of a vertical polarized wave is insignificant because of an extremely small height (thickness) of the planar waveguide. The maximal height of the planar waveguide is restricted by the thickness of the printed circuit board (PCB). Sufficient matching with space may be realized by transformation of vertical polarization to horizontal polarization.
Referring to
The exponential tapers 11 may be formed in a metal pattern extended to a metal layer respectively on the top ground 3 and the bottom ground 4. Each of the horizontal dipoles 12 may be formed into a combination of two arms. One of the two arms may be formed into a metal pattern connected to a taper formed on the top group and the other arm may be formed into a metal pattern connected to a taper formed on the bottom ground 4. Further, the director 13 may be formed into an appropriate metal pattern (for example, a square bar type) at the front of a dipole arm formed on the bottom ground 4.
Referring to
Meanwhile, the height (thickness) of the dielectric layer in the antenna having a polarization transformation structure as in some embodiments of the present disclosure may be about 0.08λ0 or larger, where λ0 is a wave length into space.
While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014129187 | Jul 2014 | RU | national |
| 10-2015-0090368 | Jun 2015 | KR | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20160020526 A1 | Jan 2016 | US |
