US2579324A - Metallic structure for delaying propagated waves - Google Patents

Metallic structure for delaying propagated waves Download PDF

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US2579324A
US2579324A US748447A US74844747A US2579324A US 2579324 A US2579324 A US 2579324A US 748447 A US748447 A US 748447A US 74844747 A US74844747 A US 74844747A US 2579324 A US2579324 A US 2579324A
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lens
elements
dielectric
metallic
wave
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US748447A
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Winston E Kock
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AT&T Corp
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Bell Telephone Laboratories Inc
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Priority to GB27274/47A priority patent/GB664672A/en
Priority to BE476703D priority patent/BE476703A/xx
Priority to NL136028A priority patent/NL74388C/xx
Priority to CH279127D priority patent/CH279127A/fr
Priority to FR1004582D priority patent/FR1004582A/fr
Priority to DEP28902A priority patent/DE844177C/de
Priority to DEP28898D priority patent/DE828412C/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
    • H01Q15/10—Refracting or diffracting devices, e.g. lens, prism comprising three-dimensional array of impedance discontinuities, e.g. holes in conductive surfaces or conductive discs forming artificial dielectric
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism

Definitions

  • This invention relates to passive devices for changing the phase velocity of electromagnetic waves and, in particular, to radio refractors designed for use in directive and non-directive antenna systems.
  • Patent 706,739 granted to R. A. Fessenden on August 12, 1902 discloses a metallic-dielectric short wave generator; Figs. 1 and 4 of Patent 1,860,123
  • the amount of reflection at the two surfaces of the dielectric material is usually fairly high, with the result that the total energy loss is appreciable and the directivity gain of the lens is not relatively high.
  • the aforesaid metallic-advance lenses are lightweight and substantially lossless; and the directivity gain is high, that is, considerably greater than that of the solid dielectric lens. Accordingly, it now appears desirable to obtain refractors, and particularly lenses, which possess the advantages, but are devoid of the disadvantages, inherent in the above-mentioned prior art structures. In particular, it appears desirable to obtain a metallic lens having distinctive attributes not found in the lenses and other structure heretofore utilized.
  • the solid dielectric delay lens is It is another object of this invention to obisotropic; and since the dielectric constant, and tain, in a metallic lens, a high gain, broad band therefore the refractive index, of the delay lens do not vary appreciably with frequency, in the frequency region in which they are employed, the lens has a relatively broad band width.
  • the end-on array mentioned above is 40 frequency sensitive since the wires are only slightly shorter than one-half the operating wavelength. a narrow may designed for two polarizations, ordinarily these lenses are suitable for utilization with only a single polariza- 'tion.
  • The.metallic-advance refractors have, however, distinct advantages not found in the metallic-dielectric phase velocity changer or the isotropic or uasi-isotropic characteristic.
  • a metallic-delay assembly or array for refracting radio waves comprises small spherical conductive elements having diameters of about three-eighths of an inch and spaced, center to center, about three-fourths of an inch apart and along three dimensions in a dielectric medium or binder, such as polystyrene foam.
  • the effective dielectric constant Bi" the three dimensional array of conductive elements is a function of the polarizability of a typical individual element and the number of elements dispersed in a unit volume of the structure comprising the foam and the array; and it is greater than unity.
  • the refractive index of the structure is greater than unity so that, in operation, the structure functions to delay or retard the phase velocity of the waves propagated therethrough.
  • the metallic delay structure is truly isotropic inasmuch as for all possible E vector directions, and therefore irrespective of the wave propagation direction, a diameter of each sphere is aligned with the E vector.
  • the structure is shaped so as to constitute a plano-hyperbolically convex diverging or positive lens.
  • the structure is shaped like a prism.
  • the disk Wpe of metallic-delay structure is anisotropic. In one sense, however, it is quasi-isotropic since the diverse diameters of each disk are parallel only to the diverse possible E polarization directions included in plane of a wave front extending parallel to the disk faces, the wave front being, of course, perpendicular to the wave propagation direction aligned with the optical axis of the structure.
  • T h e embodiment comprising disks is usually preferred over the embodiment comprising spheres because, in contrast to the spherical-elements, the thin disk elements d iahly v... he magnetic lines cf torce and ence do not dee, e a y, the expected or theoretical value of the refractive index.
  • a dielectric medium such as air, vacuum or rubber, may be utilized in the metallic delay structure. If the dielectric constant of the medium is not negligible, the over-all efi'ective dielectric constant of the refractor is dependent upon the proportions, by volume, of the medium and of the conductive array in a unit volume of the refractive structure.
  • the conductive spheres or disks in the abovedescribed embodiments may, for purpose of explanation, be considered as linear capacitative elements aligned with and spaced along the E vector, and also spaced along the propagation path. Hence, in a sense, they constitute shunt capacitors for loading free space in a manner such as to effect a reduction in the phase velocity of the space wave.
  • shunt condensers on a transmission line act as loading elements and function to reduce the wave velocity.
  • FIGs. 1 and 2 are explanatory diagrams used in explaining the invention.
  • Fig. 3 is a perspective view
  • Figs. 4 and 5 are respectively, front and side views, of a metallic-delay structure constructed in accordance with the invention
  • Fig. 6 is a side view of another metallic-delay structure constructed in accordance with the invention.
  • Figs. 7, 8 and 9 are also explanatory diagrams used in explaining the invention.
  • Figs. 10 and 11 are, respectively, perspective and side views of an isotropic metallic-delay prism constructed in accordance with the invention.
  • Figs. 12 and 13 are, respectively, perspective and side views of a directive antenna system comprising an isotropic metallic-delay, circularly symmetrical, lens constructed in accordance with the invention
  • Figs. 14 and 15 are, respectively, perspective and side views of an antenna system comprising another isotropic metallic-delay, circularly symmetrical, lens constructed in accordance with the invention
  • Fig. 16 is a side view of an antenna system comprising a quasi-isotropic metallic-delay, circularly symmetrical, lens constructed in accordance with the invention
  • Figs. 17 and 18 are, respectively, front and back views of the lens included in the system of Fig. 16, and Fig. 19 is a directive pattern of the system of Fig. 16;
  • Fig. 20 is a side view of an antenna system comprising another quasi-isotropic metallicdelay, circularly symmetrical, lens constructed in accordance with the invention
  • Figs. 21, 22 and 23 are, respectively, a tilted front view, an exploded perspective view and an enlarged detail partial side view of the lens utilized in the system of Fig. 20;
  • Fig. 24 is a perspective view of an antenna system comprising a quasi-isotropic metallic-delay, cylindrically symmetrical, lens constructed in accordance with the invention
  • Fig. 25 is an exploded perspective view of the lens used in the system of Fig. 24.
  • Fig. 26 is a side view of an antenna system comprising an isotropic circularly symmetrical, frequency sensitive, metallic-delay or metallicadvance lens constructed in accordance with the invention;
  • Figs. 27 and 28 are enlarged partial side and front views, respectively, of the lens used in the system of Fig. 26, and
  • Fig. 29 is a dispersion curve for the lens of Fig. 26.
  • reference numerals I and 2 denote, respectively, oppositely polarized unit or point-charges +q and --q, which are displaced from each other a minute LIU'HHHELEE distance and which constitute an electric dipole; and numeral 3 denotes the electric vector connecting the charges and having a length ds.
  • the potential, V, at any point. 11. resulting from a point-charge, q. is defined as the work required to move a unit charge from infinity to that point,
  • reference numeral 4 denotes a homogeneous dielectri c medium 4 in which a uniform electrostatic field E exists, the polarization of the field being represents by the arrows 5.
  • the impressed field E causes a redistribution, that is, a displacement or realignment, of the charges or charged particles in the field, and causes them to simulate electric dipoles.
  • the dielectric mediumor material is assumed to be a non-polar" or hetero-polar dielectric containing molecules which have charges, but no electric dipole moment until an electric field is applied.
  • the polarization of such materials, and the artificial dielectrics considered herein, is accordingly independent of temperature.
  • Onthe other'hand so-called polar dielectrics have arrangements of charged particles which are electric dipoles even before an external electric field is applied.
  • the applied field tends to align these dipoles and collisions produced by thermal motion tend to destroy the alignment. Accordingly, the amount of polarization, and hence the dielectric constant, which the particles exhibit depend upon the temperature.
  • Equation 1 er is the relative dielectric constant so that The cylindrical element 6 has at each transverse end an area 8, and charges +qs and qs at its ends.
  • dm is the electric dipole moment of the cylindrical space
  • dl is the length of the cylinder.
  • reference numeral I denotes a wave delay structure or device comprising a dielectric medium 8, such as air or polystyrene foam and conductive objects 9 as, for example, metallic linear elements spaced along the three dimensions X, Y and Z of the medium 8.
  • the elements 9 form a metallic array or assembly I, or so-called artificial dielectric; material, for delaying the phase velocity of electromagnetic waves.
  • Numerals II and I2 denote a arrows representing, respectively, the electric But polarization and the direction of propagation of the applied electric field E; and numerals l3 and II designate, respectively, the plane of the incoming wave front and the vertical plane of wave propagation.
  • the dimensions of the elements 9 are chosen so as to be small relative to one-half of the minimum wavelength in the propagated band, that is, amut a guarteg and preferably a much anally fraction of the afores ai d wavelength, in order to avoid regnapt egegts which may occur when the element length or dimension parallel to the E vector is in the vicinity of one-half wavelength.
  • the center-to-center spacings Sx, Sy and S, of the elements 9, along the three dimensions or axes X, Y and Z are preferably equal and less than one wavelength.
  • the spacings between adjacent elements, each of which, as explaih'edbelow, constitutes an electric dipole, should in any event be greater than the so-called breakdown yghgor inotherwordsrsufiiciently'greattopfievent short-circuiting of the elements or dipoles.
  • the minimum spacings between the elements may, if desired, be
  • An impressed electric field E having a polarizatlon II and a propagation direction l2 produces a redistribution of the charges on the conductive elements 9 and causes them to act like small electric dipoles.
  • Each of these dipoles then possesses a certain electric dipole moment which is related to the impressed electric vector and the polarizability of the individual element 9 by the equation where 7n is the electric dipole moment, a is the polarizability of the individual element I and E is the impressed electric vector.
  • F is the polarization, referred to a unit volume, of all the elements 9, that is, of the array III, as immersed in the dielectric medium 8 having a given total volume XYZ.
  • a is, as before, the dielectric constant of free space
  • n the relative dielectric constant
  • n is the refractive index of the conductive array of elements 9.
  • Equation 30 applies, strictly speaking, only when the elements 8 are suillciently far apart that their mutual eifects are negligible. In general, the mutual eifects are negligible, substantially, when the spacing between the elements is of the same order of magnitude as the size of the elements.
  • Equation 31 the value of the field, acting on and tending to polarise the elements, includes not only the incoming or impressed field E, but also the local field produced by the surrounding polarized elements.
  • the va l ue of the field includes only the impressed field E.
  • Equation 31 the assumption is made that the elements are arranged in an array having, as in the preferred arrangements of the structures disclosed herein, three-dimensional symmetry.
  • Equation 35 In determining the refractive index of the modified structure comprising a dielectric substance having a dielectric constant substantially difierent from unity, the value of cc as determined from Equation 35 should be substituted for the term t appearing in Equation 29.
  • the structure of Figs. 3, 4 and 5 is a delay or artificial dielectric structure for retarding the phase velocity of the waves.
  • the small conductive elements 9 may be regarded as capacitive elements which load free space.
  • shunt capacitors on a two-wire transmission line function to reduce the wave velocity.
  • the capacity may be increased by inserting between the plates either solid dielectric material or insulated conducting objects, provided the objects or elements each have an appreciable length in the direction of the electrostatic lines of force, that is, in a direction perpendicular to the plates.
  • the increase in capacity is caused by the shift, produced by the applied field, of the oppositely charged particles comprising the molecules of the solid material.
  • the elements cause rearrangement of the lines of force, and a consequent increase in the number of lines, similar to the rearrangement caused by the shift, mentioned above, of the oppositely charged particles.
  • the conductive elements 9, Fig. 3 may be considered as segments of individual condensers or as objects which, under the action of the applied field, function as electric dipoles and produce a dielectric polarization comparable to that resulting from the rearrangement of the charged particles comprising a non-polar dielectric. Either viewpoint or theory explains satisfactorily the delay action observed in the operation of the metallic structure of Fig. 3, and in the focussing operation of the artificial dielectric lenses to be described herein.
  • the refractive index of the conductive structure 9, Fig. 3 is directly proportional to the number N of elements 9 per unit volume of the structure. Accordingly, the refractive index, and incidentally the capacity and efiective dielectric constant, may be increased by staggering the elements 9 preferably, but not necessarily, in a manner such as to preserve the element spacing equal. The staggering should, of course, be such as to prevent short-circuiting of the elements or dipoles
  • the 10 elements may be staggered only in the vertical plane of propagation l3, or alternatively, they may be staggered, obliquely, that is, in both the plane of propagation l4 and the wave front plane l3.
  • the elements 9 are arranged in six vertical rows IS in the wave front plane l3, four vertical rows IS in .the propagation plane I and five horizontal tiers I1, the corresponding adjacentelements .5, Fig. 4, in each tier being positioned exactly in back of one another.
  • the dielectric medium 8 has the same volume, X, Y and Z, as the medium of Fig. 3.
  • the elements 9 in each vertical row It are staggered relative to the elements in the two adjacent vertical rows l8, the spacing between the elements 9 being the same as in the embodiment of Fig.
  • the dotted elements denoted by reference numerals 19 represent the positions of a few typical staggered elements when staggering only in the propagation plane H is utilized; and the dotted lines 20 illustrate the positions of a few typical staggered elements when staggering in both the wave front plane l3 and the propagation plane I4 is employed.
  • the structure of Fig. 3 should be sharply distinguished from the grid structures illustrated by Figs. 3 and 5 of my concurrently filed copending application for Transmission Systems, Serial No. 748,448, filed on May 16, 1947.
  • the element spacing in the horizontal or magnetic (H) plane may be greater than a. half wavelength whereby reflection of wave components at the surfaces or faces of the structure does not occur.
  • the H-plane spacing is less than a half wavelength so that the horizontal grid strips reflect certain portions of the E components, the unrefiected portions of the E components being propagated through the structure only along the spaces between the grid strips.
  • the structure operates to delay waves having a polarization, or a polarization component, parallel to the vector II and a propagation direction having a horizontal component such as direction l2.
  • the elements 9 may, however, have any other configuration or'shape and, in particular, F
  • a structure It comprising spherical elements, resembling ball bearings, is truly isotropic since it functions to delay equally waves having any E polarization and any propagation direction incoming to the structure.
  • a structure comprising metallic disks positioned so that their flat faces extend parallel to the incoming wave front, the optimum delay action is obtained when the incoming wave propagation direction is perpendicular, and the incoming wave front plane is parallel, to the faces of the disks.
  • the disk structure may be considered as quasiisotropic, since it functions to delay equally all E polarizations in the aforesaid wave front plane.
  • FIGs. 7, 8 and 9 the polarizability, to of a perfectly conducting sphere will now be determined.
  • denotes an originally uniform electric field such as that represented by the electric or E vector ll
  • numeral 22 designates a perfectly conducting sphere immersed in the field 2 I.
  • the free charges on the sphere are displaced by the applied field and it thereby becomes an electric dipole having a moment Me which we wish to determine.
  • the electric lines of force enter and pass through the sphere, whereby positive charges appear on one side and negative charges appear on the opposite side, as in Fig. 2, and an electric dipole is simulated.
  • Equation 30 we may obtain the refractive index of a structure In, Fig. 3, comprising spherical elements 22.
  • N is the number of spheres per unit volume of the structure.
  • n is the refractive index.
  • Equation 48 and 50 For a structure comprising perfectly conducting spheres the presence of only an electric field was assumed. In other words the magnetic field, which is inherently coupled to the electric field of an electromagnetic wave was disregarded. Actually, the magnetic field is distorted by the sphere; and this distorted magnetic field tends to reduce the value of the refractive index as given by Equation 50. More particularly, the electric vectors of the super-short wave (microwave) terminate on the conducting sphere, and the electric field is thus perturbed. These electric vectors induce eddy currentsonlthamrfacenf the conducting .wgphgre which prevent the H or magnetic lines of .force frfirh' penetrating the'surface of the sphere.
  • microwave super-short wave
  • a conductive sphere 22 immersed in a magnetic field 23 is analogous to a dielectric sphere, that is, a theoretical sphere having a zero dielectric constant, immersed in an electric field.
  • the dielectric sphere has an electric dipole moment, Ms, which we shall now determine and which corresponds in a sense to the magnetic dipole moment of the conducting sphere.
  • Equation 38 may be conveniently utilized to determine Mz-
  • Equation 63 the electric polarizability dz of a sphere having a zero dielectric constant is negative and equal to one-half the value of the polarizability (1c of the conducting sphere, as given by Equation 48.
  • the conducting sphere possesses a. negative magnetic polarizability and the effective permeability of the medium comprising conducting spheres will be altered.
  • Equation 42 rather than Equation 43 was utilized in conjunction with Equation 38 in determining its polarizability do.
  • the inside potential Vin is not zero and the inside dielectric constant sin is zero, so that Equation 43 rather than Equation 42 is employed in conjunction with Equation 38 in ascertaining its polarizability dz.
  • Equation 30 for the relative dielectric constant, er, of the element, that is.
  • the magnetic field perturbance, produced at high frequencies by the eddy current effect may be substantially eliminated by shapingt "e elements so that the magnetigjnesiareiiotlpertuiibed. More specifically, each elementmaybe' shape'cl' so as to have a neg-5 nwk 11141. 3!imnenijinnthwinter.ion. e1;- wave pro 'glgi gn and, in the direction of the elec'tri'c'field, the same dimension as in the sphere.
  • reference numeral 25 denotes a conducting circular disk having its flat faces parallel to the E vector i I and the H vector 24.
  • the first bracket represents the dipole moment, the second field: and the product is the torque.
  • the disk 25 having its plane or face parallel to E where can: is the electric polarizability of the disk.
  • the refractive index, n, for the array of disks, as given by Equation 79 is independent of the magnetic field, as already indicated.
  • reference numerals 25 denote forty-seven conductive spherical elements resembling marbles, or pellets, and mounted on vertical wooden dowels or rungs 21, the rungs 21 being supported by the wooden base member 28.
  • the pellets are dispersed or spaced along the three axes or directions, X, Y, and Z in the air dielectric medium 29 and in a manner such as to form an electromagnetic delay array 39. More particularly, the medium 29 and the array 30 together constitute a delay structure or prism 3
  • the pellets 26 are grouped in three vertical panels, namely, a front panel 34 comprising twenty-five pellets, an intermediate panel 35 comprising twelve pellets and a back panel 36 comprising ten pellets.
  • the front panel 34 comprises five horizontal tiers 31 each having five pellets
  • the middle panel comprises three horizontal tiers 38 each having four pellets
  • the back panel 36 comprises two horizontal tiers 39 each having five pellets.
  • the front panel 34 comprises five verticals or stacks 40 each having five pellets
  • the middle panel 35 comprises four vertical stacks 4
  • the back panel 36 comprises five stacks 42 each having two pellets.
  • the front and back panels 34, 36 are aligned; and the intermediate panel 35 is obliquely, that is, vertically and horizontally, staggered relative to the two outer panels 34, 36.
  • the corresponding stacks 49, 42 in the front and back panels 34, 36 are horizontally aligned and, as shown by the dotted lines 44.
  • the two tiers 39 of the back panel 36 are aligned with the two bottom tiers 3B of the front panel 34, whereby each pellet 26 in the back panel 35 occupies a position in the medium 29 corresponding, in the vertical and horizontal planes, to that occupied by a pellet in the front panel 34.
  • each pellet 11 of the middle panel 35 is positioned mid-way between two adiacent tiers 31 of the front panel 34; and each stack 4
  • the center-to-center spacings, S, between each pellet and the pellets adjacent thereto are substantially equal.
  • the electric polarizability a of each sphere or pellet is directly proportional to the cube of the radius of the pellet and, assuming the radius a is given and the mutual effects are negligible, 0. may be ascertained from Equation 50 or 62.
  • n the desired index of refraction
  • the number N of pellets per unit volume of the prism and hence the center-to-center spacing S for the pellets of known radius a may be ascertained.
  • the theoretical value of n may be ascertained.
  • the prism may contain a difierent number of pellets, and the prism may have any practical total volume.
  • the number of pellets in each panel, or tier. or in each stack may of course be considerably different from the number illustrated, provided that the desired optical configuration for the structure is preserved.
  • N equals about 2.38.
  • the dielectric medium is air, the medium may of course be any other dielectric substance.
  • the entire structure may be enclosed in an evacuated container, and the medium may be the enclosed vacuum.
  • Figs. 10 and 11 waves having a propagation direction l2 and an electric polarization ll, 8r any other polarization in the plane of the wave front I3 are propagated through the prism 3
  • reference numeral 30 designates a metallic delay array, or artificial dielectric material, which comprises, as in the array 30 of Fig. 10, conductive pellets 26 dispersed along the X, Y and Z axes in the air dielectric medium 29.
  • the array 30 comprises fifty pellets and is shaped so as to form a plano-convex circularly symmetrical delay lens 50 having a front fiat face 5
  • the refractive index, n, of the lens 50 is greater than unity and may be determined in the manner explained above in connection with the prism 3
  • the index of the lens 50 may be the same as that of the prism 3
  • Numeral 55 denotes a point type primary antenna, such as a conical horn, having its orifice coincident with the point focus 54 of the lens.
  • the horn is connected by a dielectric guide 56 to a radio translation device 51, such as a microwave transmitter, receiver or radar transceiver.
  • the pellets of the lens 50 are grouped in three panels 34, 35 and 36, the front, middle and back panels 34, 35 and 33 comprising respectively, twenty-five, sixteen and nine pellets.
  • the front panel 34 is the same as the front panel 34 of the prism 3
  • the middle panels 35 of the lens 50 comprises four tiers 38 of four pellets each, or four stacks 4
  • the back panel 35 comprises three tiers 39 of three pellets each or three stacks 42 of three pellets each. Since the lens 50 is not of solid construction the faces 5
  • the aperture 58 of the lens 50 is such that the front and back faces 5
  • the aperture 58 may be smaller than shown and such that the corresponding convex face, illustrated by the dotted line 59, and one or more outer pellets intersect, so that a portion of each intersected pellet lies outside the lens and the remaining portion is included in the lens.
  • the pellet portions external to the lens should be removed, in order to secure the desired optical contour.
  • the lens may comprise only whole pellets, or both.
  • the reference letter A denotes the phase length of the path traversed by a wavelet r ray emitted at the focus 84 and propagated through the thick vertex portion of the lens and along the lens axis 53 to the flat front face II.
  • Reference letter B denotes the phase length of the path traversed by a ray emanating from the focus 54 and propagated to the periphery so as to just avoid the lens and reach the front face SI.
  • f is the focal length of the lens
  • a is the lens thickness along the axis 03
  • 0 is the phase velocity in the lens, as before, and no is the phase velocity in free space.
  • Figs. 12 and 13 assuming the device 51 is a transmitter, energy is supplied by the transmitter 81 over guide 58 to the horn 55 and a wave having a polarization I I and a spherical wave front is propagated towards the lens 50.
  • the phase of the wave components passing through the thick central of vertex portion of the lens are retarded a greater amount than the phase of the wavelets propagated through the outer thinner lens portion. and the wavelets arriving at the front face SI are cophasal.
  • an outgoing spherical wave front 80 is converted by the lens to a plane front I extending perpendicular to the axis I8.
  • the converse operation sndanincaa iasml e havin .apm
  • ation direc rallel to the E53 is t ransnmailquama -view lens into a spherical wave.fioiiijj pgifieggingknjthe "focus 84.
  • the incoming parallel rays 62, 88 are bent or refracted by the lens, as illustrated by the rays 84, 85 and focussed on the primary antenna 55.
  • focussing action is obtained in all planes containing the optical axis 83.
  • the lens 80 is isotropic.
  • a lens constructed in accordance with Figs. 12 and 13 and comprising pellets having diameters of three-eighths of an inch and spaced center-to-center threequarters of an inch operated in a highly satisfactory manner.
  • the piano-convex lens of Figs. 14 and 15 is the same as the lens of Figs. 12 and 13 except that polystyrene foam having a dielectric constant of 1.014, that is, substantially unity, and
  • a refractive index of 1.007, also substantially unity, is utilized in place of air as the dielectric medium.
  • reference numerals II, I2 and I3 denote three thick polystyrene foam slabs in which the pellets 26 of panels 84, 35 and 36 are embedded, respectively.
  • Numerals I4 and I5 denote two thin polystyrene foam spacer sheets included, respectively, between slabs II and I2 and slabs I2 and I3.
  • the panels 34, 35 and I6 constituting the metallic delay lens I0 are substantially the same as the panels 84, 35 and 38 of the lens 50.
  • the operation of the system of Figs. 14 and 15 is substantially the same as that of Figs. 12 and 13.
  • the pellets 28 were three-eighths of an inch in diameter and spaced center-to-center three-quarters of an inch.
  • reference numeral denotes a quasi-isotropic, circularly symmetrical, delay lens comprising a dielectric medium 8
  • comprises five closely adjacent circular slabs 83, 84, 85, 80 and 81 of polystyrene foam and the negligible air dielectric 88 between the adjacent parallel slabs.
  • , 92 and 93 denote the front surfaces, and numerals 94, 95, 98, 81 and designate the back surfaces, of the slabs 88, 84, 85, 86 and 81, respectively.
  • the slabs are coaxially supported on the wooden cross-member or rung 99, the wooden uprights I00 and the wooden base member 28.
  • the metallic delay array 82 comprises a large number of copper foil disks IOI having negligible thickness and mountediinthe back surfaces of the five slabs, and on the front surface of slab 83, in a manner such that the conductive disks are uniformly dispersed along three dimensions in the medium 8
  • the metallic delay structure comprises six circular metallic panels I02, I08, I04, I05, I08 and I01 spaced equally along the optical axis 53 of the lens 80 and comprising different pluralities of metallic disks I0l.
  • Each panel contains whole and fractional disks.
  • the disks MI in panels I03, I05 and I01 are obliquely staggered relative to the disks III in panels I02, I04, and I06.
  • Numerals I08 denote polystyrene foam spacers mounted on the rung 99 between the slabs and adjacent the outer slabs, and preferably dimensioned so that the center-to-center spacings S of the adjacent disks in the adjacent panels and the center-to-center spacings S of the adjacent disks in each panel are equal.
  • the spacers I08 may be omitted and the slabs 83 to 81 may each have a thickness such as to render the slabs contiguous, whereby the air spacing between slabs is eliminated, substantially.
  • the diameters of the slabs, and hence of the panels, are progressively stepped in conformity with the piano-convex shape of the lens.
  • each disk IN is directly proportional to the cube of the radius R of the disk and, assuming the radius is given. may be ascertained from Equation '18.
  • the radius R aidthe desired index of refraction n selected
  • the number N of disks per unit volume of the metallic lens 80. and hence the 'one'si'de of each of many center-to-center spacing, S, of the disks may be determined from Equation 79, assuming mutual elfects are disregarded, or from Equations 31 and 78 if the mutual effects are considered.
  • R and N, and therefore S, selected the theoretical value of 11 may be ascertained.
  • the lens of Fig. 12 or Fig. 14 is essentially the same as that of the lens of Fig. 12 or Fig. 14.
  • the lens 30 is, however, isotropic only for waves having a propagation direction parallel to the axis 53 whereas, as stated above, the lens 50 and the lens 10 are each truly isotropic. As in the lenses 50 and 10, focussing obtains in all axial planes of the lens 80 and a pencil or point type beam is produced.
  • Fig. 19 in which reference numeral I I denotes the measured E-plane directive pattern for an antenna system constructed in accordance with Figs. 16, 17 and 18, the directive action of the small delay lens 80 is highly satisfactory.
  • the lens diameter or aperture, the disk radius R and t h e d isk spacing S were, respectively twenty-four inches, flve-sixteenths of an inch, andmeinch; and the pattern was measured at a design wavelength of x equal to 1.2 5
  • the pattern IIO comprises a single major IoBe I II, the two vestigial lobes H2 and the minor lobes II3.
  • the vestigial and minor lobes are considerably below the peak of the major lobe, the vestigial lobes being 15 decibels and the minor lobes being 20-25 decibels down from the peak.
  • the relative intensity of the minor lobes is, in general, more satisfactory than obtained in prior art reflective antenna structures.
  • the half-power width II 4 of the major lobe is 7.6 degrees. This beam or lobe width is dependent upon several factors including the focussing action of the lens, and it is also directly proportional to the lens aperture.
  • the 7.6 degrees beam width for the lens of the invention is comparable to the beam widths of other prior art passive antenna members, such as parabolic reflectors, zone plate and other lenses, having two-foot apertures. It may be observed that, as disclosed in my companion application, a polarized metallic delay strip lens having a six-foot aperture has a half-power beam width of only 2.68 degrees. Hence, the beam width of a lens constructed in accordance with Figs. 16, 17 and 18 and having a six-foot aperture would be about 2.68 degrees.
  • a delay lens of the disk type may,
  • reference numeral I20 designates a quasi-isotropic, circularly symmetrical, delay lens comprising four solid dielectric spacer sheets I23, I25, I21 and I29 and five solid dielectric panel sheets I22, I24, I26, I28 and I30.
  • Reference numerals I32, I33, I34, I and I36 denote circular panels painted on the panel sheets I22, I24, I26, I28 and I30, respectively, and having graded diameters tapering from a maximum for panel I32 to a minimum for panel I36 in conformity with the convex hyperbolic optical face 52 of the lens I20.
  • the panels comprise difierent pluralities of square dot es or moteg lgl of conductive paint, and are not staggered.
  • the adjacent motes I31 of each panel'efi spaced a distanges; and the thicknesses of the panel and spacer sheets are selected such that the corresponding motes in adjacent panels are spaced a distance S.
  • the panel and spacer sheets, assembled as shown in Fig. 20, are held securely together by the wooden frame members I2I and the nut and bolt assemblies I3I.
  • the panel and spacer sheets may be ,composed of polystyrene foam or other suitable dielectric material such as cellophane. If the material is transparent, the motes I31 produce a shading effect, as shown in Fig. 21, which decreases in all radial directions from a maximum intensity at the center of the lens to a minimum at the periphery, by reason of the circular symmetry of the lens.
  • the electric polarizability a of the individual square mote having a side length 2R is not substantially different from the polarizability a of a circular mote having a radius R.
  • the p01arizability a may be ascertained from Equation 78, as in the lens of Fig. 16.
  • the desired refractive index 11 greater than unity may be obtained by properly selecting N and S in accordance with Equation 79.
  • the quasi-optical and electrical operation of the system of Fig. 20 is substantially the same as that of the system of Fig. 16.
  • the metallic delay painted disk lens I40 is substantially the same as the painted lens I20 of Figs. 20, 21, 22 and 23, except that the lens I40 is cylindrically symmetrical and has a line focus I4I, whereas the lens I20 is circularly symmetrical and has a point focus 54.
  • of the lens I40 is cylindrically convex and the back face 52 is fiat.
  • the lens I40, Figs. 24 and 25, comprises five polystyrene foam rectangular slabs I42, I43, I44, I45 and I46 and the five conductive panels I41, I48, I49, I50 and I5I, sprayed on the aforesaid slabs. respectively.
  • the panels are not staggered and they have equal lengths but graded widths.
  • the motes I31 are of conductive paint.
  • the slab thicknesses are such that the spacings s between adjacent motes I37 and along the three dimensions X, Y and Z of the structure, are equal.
  • Numeral I52 denotes a sectoral horn connected to guide 56 and device 51 and having its long mouth aperture I53 aligned with the focal lens I of the lens I40.
  • the mote polarizability a the mote side halflength R, the number N of motes per unit volume of the structure, the spacing s between motes and the refractive index n are the same as in the lens of Fig. 20.
  • the sectoral horn energizes the focal line I and the lens delays the inner rays passing through the thicker lens portion relative to the outer rays.
  • the cylindrical wave front emerging from the horn mouth aperture I52 and aligned with the line focus I is transformed by the lens III to a plane wave.
  • the lens focusses the waves in the E or vertical plane containing the electric polarization II but does not focus in the H or horizontal plane. Accordingly, a fan beam is produced having a small width in the E-plane and a large width in the H-plane.
  • a point beam may be secured by properly inserting a lens in the horn mouth aperture I52, as is well known.
  • the E dimension that is. the dimension as measured in a direction parallel to the electric wave polarization, of each conductive element in the structures described thus far is relatively small compared to a half wavelength, and therefore such as to avoid resonant eifects.
  • the structures illustrated by Figs. 3, 10, 12, 14, 16, 20 and 24 have a relatively broad band with, since the frequency bands or regions in which they are ordinarily used are sufficiently remote, from the region of anomalous dispersion,
  • the effective dielectric constant and the refractive index do not vary appreciably with frequency.
  • the index 11 increased only 0.02 as the wavelength decreased one centimeter, that is, as the frequency increased 535.7 megacycles.
  • As the frequency increases from 4,285.7 megacycles, the index 1
  • the metallic structure is opaque and the index n is very high.
  • the E dimension of the elements is a half wavelength, whereby resonant efiects occur and the artificial dielectric or metallic structure acts like an ordinary solid dielectric substance near its region of anomalous dispersion.
  • the metallic structure appears to have an index of refraction less than unity. With the index 11. less than unity, the phase velocity of the waves propagated therethrough is accelerated rather than retarded, and the refractor becomes a fast metallic advance refractor.
  • linear elements or rods p0- sitioned parallel to the E vector and having an E dimension or length of a half wavelength have a very broad resonance band, and the region or range of anomalous dispersion in a metallic artiflcial dielectric structure comprising such rods is very large.
  • This region, or frequency band may be considerably reduced by tilting the half wave rods in the wave front plane, so that they are more nearly perpendicular to the electric (E) vector, whereby the rods become loosely coupled to the moving field and acquire a higher "62.
  • the rods should be unsymmetrically or dissimilarly tilted in order to insure a rapid decrease in the radiation damping, and hence a sharp resonant characteristic, and to minimize radiation from the array of rods. symmetrically tilting the rods would result in maximum radiation from the array of a wave polarized parallel to the rods.
  • reference numeral I 60 denotes a frequency-sensitive metallic artificial dielectric structin-e comprising a plurality of resonant 1 u on. each a half wavelength long a given frequency and disposed in four vertical panels 162, I02, I and I05.
  • the rods I are arranged in ten horizontal tiers I66.
  • the adiacent rods Iii in each panel areoppositely tilted.
  • the corresponding rods I61 in each tier are embedded in the same polystyrene foam horizontal slab I61, as illustrated, the thickness or vertical height of each slab being approximately the same as the vertical projection"Lv" of the rod length "L.”
  • Numerals I denote polystyrene spacer slabs each of which is positioned between a different pair of adjacent tier slabs I61.
  • the rod tilt is such that the center-to-centerhorizontal spacing Bx of the rods is about three times the vertical center-to-center spacing 8,. of the rods, and the horizontal rod spacing Se is about one half the horizontal S4 spacing, the spacings S, being preferably less than one quarter of the aforesaid given wavelength.
  • the front face It! of the structure I" is circular and flat.
  • the back face is circularly convex 0r circularly concave, as shown by the dot-dash lines I10 and "I, Fig. 26. dependent upon the operating frequency of the translation device I12.
  • the device I12 includes means for varying the operating frequency or is designed so that the frequency may be easily altered.
  • Fig. 26 assuming the operating frequency of device I12 is higher than any of the frequencies included in the anomalous dispersion region for the structure I", the dielectric constant and refractive index of the structure are each less than unity and the phase velocity, v, of the waves in the lens I" is greater than the phase velocity, D0. of free space. Accordingly. the back face of the lens I" is made ellipsoidally concave, in accordance with the disclosure in my aforesaid copending application Serial No. 642,723.
  • the dielectric constant and refractive index of the structure are each greater than unity and the phase velocity, v, of the waves in the lens I is smaller than the free space phase velocity, 170. Accordingly, in this case, the back face is hyperbolically convex. as in the structure illustrated, for example. by Fig. 13. In either case the lens I" functions to focus the waves in all planes containing the lens axis 52, as already explained.
  • reference number I12 denotes a measured dispersion curve of a metallic structure constructed in accordance with Figs. 26, 27 and 28 and in which L, In, S, S, and S; were respectively 1.25 inches, 0.25 inch, 1.5 inches. 0.5 inch and 0.75 inch. In the test, the operating wavelength was 7.6 centimeters. As shown by curve I13 the re ion of anomalous dispersion for the tested metallic structure I" occurs when the rods I6I are approximately a half wavelength long. In other words.
  • the curve shows that the structure is resonant at a frequency of about 3,947 megacycles, and at this frequency the 1.25 inch, or 3.175 centimeter, rods are almost a half wavelength long since 3,947 megacycles correspond to 7.60 centimeters.
  • the structure I has an anomalous dispersion region analogous to that of a solid dielectric refractor.
  • the artificial di- 23 electric "I may be utilized, in prisms or variable focal length lenses, as a means for separating narrow channels.
  • a slow lens in accordance with Fig. 16, for example may be combined with the fast dielectric channel lens of my copendin application, Serial No. 642,723, to secure a compound achromatic metallic fast-slow lens.
  • a piano-convex metallic lens for retracting a radio wave comprising flat circular conductive disks mounted on solid dielectric members and spaced along three directions in said lens, the flat faces of said disks being parallel to the electric polarization of said wave, said disks having equal diameters each less than one-half of the wavelength of said wave.
  • a piano-convex, circularly symmetrical, lens for refracting a radio wave having a given wavelength said lens comprising circular polystyrene ioam slabs extending parallel to each other, a plurality of metallic disks mounted on each slab, the spacing between adjacent slabs and between adjacent disks on the same slab being less than the wavelength of said wave and the diameter of each disk being less than onehaif of said wavelength.
  • a device for retracting electromagnetic waves comprising a plurality of arrays of conductive elements said elements being substantially alike and having a maximum dimension which is small with respect to the wavelength of the median frequency of said range of wavelengths, each of said arrays comprising a plurality of said conductive elements substantially uniformly distributed over the entire surface of a plane area, the major dimensions of said area being large with respect to said maximum element dimension, the spacings between adjacent elements not exceeding three times the said maximum dimen- 24 sion of said elements, said plurality of arrays being placed with their respective planes parallel to each other along a common axis perpendicular to said planes, the spacings between the planes of adjacent arrays being substantially the same as the inter-element spacings of the arrays.
  • contour lines defined by the outermost edges of the outermost elements of the plurality of arrays of elements are substantially those of a piano-convex lens.
  • contour lines defined by the outermost edges of the outermost elements of the plurality of arrays of elements are those of a simple type of optical retractor.

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  • Aerials With Secondary Devices (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
US748447A 1947-05-16 1947-05-16 Metallic structure for delaying propagated waves Expired - Lifetime US2579324A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US748447A US2579324A (en) 1947-05-16 1947-05-16 Metallic structure for delaying propagated waves
GB27274/47A GB664672A (en) 1947-05-16 1947-10-10 Improvements in or relating to devices for changing the phase velocity of electromagnetic waves
BE476703D BE476703A (xx) 1947-05-16 1947-10-14
NL136028A NL74388C (xx) 1947-05-16 1947-11-13
CH279127D CH279127A (fr) 1947-05-16 1948-04-19 Réfracteur pour ondes électromagnétiques.
FR1004582D FR1004582A (fr) 1947-05-16 1948-05-10 Perfectionnements aux systèmes de transmission
DEP28902A DE844177C (de) 1947-05-16 1948-12-31 Anordnung zur Verringerung der Phasengeschwindigkeit elektromagnetischer Wellen
DEP28898D DE828412C (de) 1947-05-16 1948-12-31 Brechungskoerper fuer elektromagnetische Wellen

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US748447A US2579324A (en) 1947-05-16 1947-05-16 Metallic structure for delaying propagated waves

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BE (1) BE476703A (xx)
CH (1) CH279127A (xx)
DE (2) DE828412C (xx)
FR (1) FR1004582A (xx)
GB (1) GB664672A (xx)
NL (1) NL74388C (xx)

Cited By (22)

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US2670462A (en) * 1949-05-28 1954-02-23 Sponge glass seal for wave guides
US2716190A (en) * 1951-02-23 1955-08-23 Dow Chemical Co Dielectric material
US2805728A (en) * 1953-08-27 1957-09-10 Gen Dynamics Corp Sound dispersion device with internal divergent acoustical lens
US2820206A (en) * 1952-05-08 1958-01-14 Itt Microwave filters
US2870439A (en) * 1950-12-29 1959-01-20 Western Union Telegraph Co Microwave energy attenuating wall
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US3087574A (en) * 1959-11-05 1963-04-30 Bolt Beranek & Newman High acoustic transmission loss panel and the like
US3089142A (en) * 1959-10-30 1963-05-07 Sylvania Electric Prod Artificial dielectric polarizer
US3165749A (en) * 1958-09-15 1965-01-12 Thompson Ramo Wooldridge Inc Microwave transmissive optical radiation reflectors
US3214760A (en) * 1960-04-28 1965-10-26 Textron Inc Directional antenna with a two dimensional lens formed of flat resonant dipoles
US3320685A (en) * 1964-04-29 1967-05-23 Welch Scient Company Diffraction apparatus
US3430248A (en) * 1966-01-06 1969-02-25 Us Army Artificial dielectric material for use in microwave optics
US3887920A (en) * 1961-03-16 1975-06-03 Us Navy Thin, lightweight electromagnetic wave absorber
EP0527714A1 (en) * 1991-08-12 1993-02-17 CelsiusTech Electronics AB Cavity Antenna
US10142096B2 (en) 2016-08-01 2018-11-27 Movandi Corporation Axial ratio and cross-polarization calibration in wireless receiver
US10199717B2 (en) 2016-11-18 2019-02-05 Movandi Corporation Phased array antenna panel having reduced passive loss of received signals
US10256537B2 (en) * 2016-10-26 2019-04-09 Movandi Corporation Lens-enhanced phased array antenna panel
US10291296B2 (en) 2016-09-02 2019-05-14 Movandi Corporation Transceiver for multi-beam and relay with 5G application
US11018752B2 (en) 2017-07-11 2021-05-25 Silicon Valley Bank Reconfigurable and modular active repeater device
CN113067159A (zh) * 2021-03-23 2021-07-02 北京大学 一种高效无限通道行波-表面波天线及其实现方法
CN116387843A (zh) * 2023-04-12 2023-07-04 广东福顺天际通信有限公司 一种介质颗粒
EP4238186A4 (en) * 2020-10-27 2024-03-27 Guangzhou Sigtenna Technology Co., Ltd ARTIFICIAL DIELECTRIC MATERIAL AND FOCUSING LENSES MADE THEREOF

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1186406A (en) * 1982-05-21 1985-04-30 Her Majesty The Queen In Right Of Canada As Represented By The Minister Of National Defence Of Her Majesty's Canadian Government Dipole array lens antenna
GB2145575A (en) * 1983-05-25 1985-03-27 British Telecomm Mounting dielectric resonators
CA1221750A (en) * 1983-11-21 1987-05-12 Richard D. Carver Mounting dielectric resonators

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FR327312A (fr) * 1902-12-13 1903-06-19 Germain Nouveau genre de lentilles applicable à tous les appareils d'optique
DE587771C (de) * 1928-03-22 1933-11-08 Aeg Hochspannungsisolator und Verfahren zu seiner Herstellung
US2289735A (en) * 1941-02-07 1942-07-14 Smith Lewis Heating system
US2298272A (en) * 1938-09-19 1942-10-13 Research Corp Electromagnetic horn
US2317464A (en) * 1940-10-29 1943-04-27 Rca Corp Electromagnetic wave horn radiator
US2403657A (en) * 1943-01-29 1946-07-09 Rca Corp Insulating and dielectric material
US2415352A (en) * 1944-04-22 1947-02-04 Rca Corp Lens for radio-frequency waves
US2415807A (en) * 1942-01-29 1947-02-18 Sperry Gyroscope Co Inc Directive electromagnetic radiator
US2423643A (en) * 1943-04-22 1947-07-08 American Cyanamid Co Condensation products of guanylurea with alkylene oxides
US2464269A (en) * 1942-06-12 1949-03-15 Raytheon Mfg Co Method and means for controlling the polarization of radiant energy

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US706739A (en) * 1901-05-29 1902-08-12 Reginald A Fessenden Conductor for wireless telegraphy.
FR327312A (fr) * 1902-12-13 1903-06-19 Germain Nouveau genre de lentilles applicable à tous les appareils d'optique
DE587771C (de) * 1928-03-22 1933-11-08 Aeg Hochspannungsisolator und Verfahren zu seiner Herstellung
US2298272A (en) * 1938-09-19 1942-10-13 Research Corp Electromagnetic horn
US2317464A (en) * 1940-10-29 1943-04-27 Rca Corp Electromagnetic wave horn radiator
US2289735A (en) * 1941-02-07 1942-07-14 Smith Lewis Heating system
US2415807A (en) * 1942-01-29 1947-02-18 Sperry Gyroscope Co Inc Directive electromagnetic radiator
US2464269A (en) * 1942-06-12 1949-03-15 Raytheon Mfg Co Method and means for controlling the polarization of radiant energy
US2403657A (en) * 1943-01-29 1946-07-09 Rca Corp Insulating and dielectric material
US2423643A (en) * 1943-04-22 1947-07-08 American Cyanamid Co Condensation products of guanylurea with alkylene oxides
US2415352A (en) * 1944-04-22 1947-02-04 Rca Corp Lens for radio-frequency waves

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2670462A (en) * 1949-05-28 1954-02-23 Sponge glass seal for wave guides
US2870439A (en) * 1950-12-29 1959-01-20 Western Union Telegraph Co Microwave energy attenuating wall
US2716190A (en) * 1951-02-23 1955-08-23 Dow Chemical Co Dielectric material
US2820206A (en) * 1952-05-08 1958-01-14 Itt Microwave filters
US2805728A (en) * 1953-08-27 1957-09-10 Gen Dynamics Corp Sound dispersion device with internal divergent acoustical lens
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US3165749A (en) * 1958-09-15 1965-01-12 Thompson Ramo Wooldridge Inc Microwave transmissive optical radiation reflectors
US3089142A (en) * 1959-10-30 1963-05-07 Sylvania Electric Prod Artificial dielectric polarizer
US3087574A (en) * 1959-11-05 1963-04-30 Bolt Beranek & Newman High acoustic transmission loss panel and the like
US3214760A (en) * 1960-04-28 1965-10-26 Textron Inc Directional antenna with a two dimensional lens formed of flat resonant dipoles
US3887920A (en) * 1961-03-16 1975-06-03 Us Navy Thin, lightweight electromagnetic wave absorber
US3320685A (en) * 1964-04-29 1967-05-23 Welch Scient Company Diffraction apparatus
US3430248A (en) * 1966-01-06 1969-02-25 Us Army Artificial dielectric material for use in microwave optics
EP0527714A1 (en) * 1991-08-12 1993-02-17 CelsiusTech Electronics AB Cavity Antenna
US10142096B2 (en) 2016-08-01 2018-11-27 Movandi Corporation Axial ratio and cross-polarization calibration in wireless receiver
US10291296B2 (en) 2016-09-02 2019-05-14 Movandi Corporation Transceiver for multi-beam and relay with 5G application
US10256537B2 (en) * 2016-10-26 2019-04-09 Movandi Corporation Lens-enhanced phased array antenna panel
US10199717B2 (en) 2016-11-18 2019-02-05 Movandi Corporation Phased array antenna panel having reduced passive loss of received signals
US11056764B2 (en) 2016-11-18 2021-07-06 Silicon Valley Bank Phased array antenna panel having reduced passive loss of received signals
US11018752B2 (en) 2017-07-11 2021-05-25 Silicon Valley Bank Reconfigurable and modular active repeater device
EP4238186A4 (en) * 2020-10-27 2024-03-27 Guangzhou Sigtenna Technology Co., Ltd ARTIFICIAL DIELECTRIC MATERIAL AND FOCUSING LENSES MADE THEREOF
CN113067159A (zh) * 2021-03-23 2021-07-02 北京大学 一种高效无限通道行波-表面波天线及其实现方法
CN113067159B (zh) * 2021-03-23 2022-01-28 北京大学 一种高效无限通道行波-表面波天线及其实现方法
CN116387843A (zh) * 2023-04-12 2023-07-04 广东福顺天际通信有限公司 一种介质颗粒
CN116387843B (zh) * 2023-04-12 2023-09-12 广东福顺天际通信有限公司 一种介质颗粒

Also Published As

Publication number Publication date
DE844177C (de) 1952-07-17
BE476703A (xx) 1947-11-29
CH279127A (fr) 1951-11-15
FR1004582A (fr) 1952-03-31
GB664672A (en) 1952-01-09
NL74388C (xx) 1953-11-16
DE828412C (de) 1952-02-28

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