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WO1996003783A1 - Antennes en microruban a double anneau - Google Patents

Antennes en microruban a double anneau Download PDF

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Publication number
WO1996003783A1
WO1996003783A1 PCT/US1995/009284 US9509284W WO9603783A1 WO 1996003783 A1 WO1996003783 A1 WO 1996003783A1 US 9509284 W US9509284 W US 9509284W WO 9603783 A1 WO9603783 A1 WO 9603783A1
Authority
WO
WIPO (PCT)
Prior art keywords
edge
microstrip antenna
ring
antenna
radiating patch
Prior art date
Application number
PCT/US1995/009284
Other languages
English (en)
Inventor
Mohamed S. Sanad
Original Assignee
Wireless Access Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wireless Access Incorporated filed Critical Wireless Access Incorporated
Priority to AU31424/95A priority Critical patent/AU3142495A/en
Publication of WO1996003783A1 publication Critical patent/WO1996003783A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/0421—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with a shorting wall or a shorting pin at one end of the element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
    • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas

Definitions

  • the present invention relates to small microstrip antennas for use in electronic devices.
  • the invention relates to microstrip antennas suitable for use in portable electronic devices which operate in close proximity to humans or other electronic equipment while positioned in a variety of orientations, yet are small enough to fit within a credit card size pager, a portable telephone, or a portable computer.
  • Advances in digital and radio electronics have resulted in the production of a new breed of personal communications equipment posing special problems for antenna designers. These systems are typically small in size and may be easily carried by a user. Some, such as pagers, are designed to fit inside a user's pocket and are expected to reliably receive signals while in that position. Such placement can be a problem, as proximity of the human body to various types of antennas results in degraded radiation of the antenna. This phenomenon is sometimes termed the "body effect" and can alter an antenna's resonant frequency as well as its gain. Antennas used in such an environment need to take into account the signal-degrading effects present near a human body or the like.
  • any antenna used must have a small overall size and a low profile.
  • a microstrip antenna comprises a dielectric sandwiched between a conductive ground plane and a planar radiating patch.
  • Microstrip antennas are useful alternatives for applications requiring a small and particularly thin overall size.
  • Microstrip antennas are commonly produced in half wavelength sizes, in which there are two primary radiating edges parallel to one another. It is known that the size may be further reduced if all of one of the primary radiating edges of a half wavelength antenna is short circuited, permitting the length to be reduced to approximately a quarter wavelength. These antennas are recognized to be useful in applications requiring a low-cost small antenna which is generally linearly-polarized.
  • microstrip antennas may be changed by varying the shape or "geometery" of the antenna.
  • Many different geometries for microstrip antennas have been developed with resulting differences in radiation patterns and resonant frequencies. For example, numerous geometries are shown in the HANDBOOK OF MICROSTRIP ANTENNAS, James and Hall, eds., Peter Peregrinus Ltd., London, UK, 1989, pp. 24-39.
  • microstrip antennas have many advantageous characteristics, they do not meet the special demands of miniature personal communications electronics for several reasons: they are vulnerable to human body effects; they are difficult to tune without changing the overall shape or size of the dielectric or radiator; they generally do not exhibit isotropic radiation patterns; they are generally linearly-polarized; and they are typically too large to fit within small communications devices when designed for operation at frequencies of interest, typically below 1 GHz.
  • microstrip antenna of a design having a reduced size which has a low resistance to human body effects while exhibiting substantially isotropic radiation patterns. It would be a further advantage to provide such an antenna with advanced tuning capabilities while remaining relatively inexpensive to manufacture.
  • a microstrip antenna having a reduced size which produces substantially isotropic radiation patterns while showing minimal degradation in performance when operated in close proximity to other electronics or the human body.
  • a microstrip antenna includes a ground plane and a radiating patch, each made of conductive material, and a dielectric layer positioned between the ground plane and the radiating patch, which together form a rectangular antenna structure having two side edges, a main radiating edge, and a short circuit edge.
  • a short circuit provided along one of the edges creates a "mirror" image of the radiating patch relative to the shorted edge.
  • the short-circuited edge may be fully shorted, or in accordance with the invention may be shorted along only a portion or selected portions of the short circuit edge, relative to the wavelength, as is discussed in the co- pending patent application Serial No. 08/049,514, entitled “A SMALL MICROSTRIP ANTENNA HAVING A PARTIAL SHORT CIRCUIT", by Mohamed S. Sanad, filed on April 19, 1993, and incorporated herein by reference.
  • the radiating patch also includes a ring area cut ⁇ out from the patch, exposing a portion of the dielectric material underneath the radiating patch.
  • the ring may have a rectangular shape, as disclosed in the co-pending patent application, Serial No. 08/049,560, entitled “A SMALL, DOUBLE RING MICROSTRIP ANTENNA", by Mohamed S. Sanad, filed on April 19, 1993, and incorporated herein by reference.
  • the ring may also have a triangular, circular, diamond, or other shape.
  • the ring is offset so that it is closer to the shorted edge than to the radiating edge.
  • the ring could be centered, or shifted closer to the radiating edge.
  • the distance between the radiating edge and the edge of the ring proximate thereto is maximized in order to reduce the length of the antenna.
  • the desired input impedance can be selected by varying the length between the edge of the ring and the shorted side, and by varying the two dimensions between the edges of the rings and the two nonradiating edges. Adjustment of other features, such as trimming the nonradiating edges closely to the ground plane, can further enhance the isotropic nature of the radiation pattern.
  • the antenna is formed in a shape that is compatible with Personal Computer Memory Card International Association (hereinafter, "PCMCIA”) standards, including size, shape and radiation characteristics, allowing it to fit within a PCMCIA card for easy installation in a variety of types of electronic equipment.
  • PCMCIA Personal Computer Memory Card International Association
  • Other shapes and sizes of the antenna will allow it to be used in a wide range of communication equipment.
  • FIG. 1 is a perspective view of a prior art quarter wavelength microstrip antenna
  • Fig. 2 is a perspective view of one embodiment of a double triangular ring microstrip antenna
  • Fig. 3 is a perspective view of another embodiment of a double triangular ring microstrip antenna
  • Fig. 4 is a perspective view of a double diamond ring microstrip antenna
  • Fig. 5 is a perspective view of a double circular ring microstrip antenna
  • Figs. 6A, 6B, and 6C are partial perspective views of alternative shorting schemes which may be utilized with the antennas of the present invention.
  • Fig. 7 is a perspective view of a microstrip antenna installed within a pager.
  • Fig. 1 is a view of a prior art quarter-wavelength microstrip antenna 100.
  • the antenna includes a dielectric layer 110 sandwiched between a conductive ground plane 120 and a conductive radiating patch 130.
  • the ground plane 120 and the radiating patch 130 are electrically connected by short circuit 140.
  • the radiating patch 130 is energized by connection through a coaxial cable 150 to feed point 160.
  • a radiating patch 130 which is approximately 57 mm in length in order to achieve a resonant frequency of 863 MHz in free space. This resonant frequency was achieved using a dielectric 110 having a dielectric constant of 2.2, and which is 2.286 mm thick.
  • a typical quarter wavelength microstrip antenna designed for operation at 863 MHz, is 69 mm long by 52 mm wide.
  • Fig. 2 a quarter wavelength microstrip antenna 200 having a double triangular ring 250 is shown.
  • the microstrip antenna 200 has a resonant frequency of approximately 931.5 MHz, a frequency which is allocated for use by personal pagers.
  • the dimensions given may be scaled in order to achieve other resonant frequencies.
  • the microstrip antenna 200 includes a ground plane 212 formed of a conductive material.
  • a dielectric layer 214 is positioned proximate the ground plane 212.
  • a radiating patch 216 is formed on the side of the dielectric layer 214 opposite the ground plane 212.
  • the dielectric layer 214 is 0.43 mm thick, and a dielectric such as Duroid 5880 is used.
  • Duroid 5880 has a relative permittivity of approximately 2.2 and is available from Rogers Corporation, Chandler, Arizona.
  • the radiating patch 216 preferably has a thickness of 1.0 oz./m 2 of copper foil.
  • the microstrip antenna 200 includes four sides: a primary radiating edge 220 opposite a shorted edge 222; and a first side edge 224 opposite a second side edge 226. Even though the side edges 224 and 226 may be termed "nonradiating" edges, an amount of radiation will normally be emitted from them. However, that amount is small in comparison to the radiation emitted from the primary radiating edge 220.
  • the primary radiating edge 220 is open circuited along its entire length, as is the first side edge 224 and the second side edge 226.
  • shorted edge 222 is short circuited along its entire length. Specifically, the shorted edge 222 couples the radiating patch layer 216 to the ground plane 212.
  • the shorted edge 222 may comprise any conductive material.
  • a wrapped copper foil is utilized.
  • the copper foil may be similar to the foil that is used to form the radiating patch 216.
  • a plurality of shorting posts is utilized. This embodiment is discussed infra in conjunction with Fig. 6. A more detailed discussion is given in co-pending patent application Serial No. 08/281,875 , entitled "SHORTING POSTS
  • the shorted edge may comprise one or more partial short circuits.
  • a feed point 240 is positioned proximate to the shorted edge 222, and approximately centered within the width of the antenna L ⁇ . The position of the feed point 240 is selected so that the input impedence is 50 ohms in the intended environment of operation.
  • the feed point 240 is, in one particular embodiment, connected to a conventional coaxial cable 242.
  • the coaxial cable 242 is attached so that its outer conductor is coupled to the ground patch 212, and its center conductor is coupled to the radiating patch 216 at the feed point 240.
  • a microstrip feed may be utilized. This embodiment is shown and discussed infra in conjunction with Fig. 6, and is described more fully in co- pending patent application, Serial No. 08/283,064 t entitled “MICROSTRIP ANTENNA HAVING A MICROSTRIP FEED", by Mohamed S. Sanad, filed on 29 July 1994 and incorporated herein by reference. Other conventional techniques may also be utilized in connecting the antenna.
  • the input impedence of the antenna 200 is selected to match 50 ohms, typically the characteristic impedence of the coaxial transmission line 242.
  • 50 ohms typically the characteristic impedence of the coaxial transmission line 242.
  • An aperture or ring 250 is positioned proximate the feed point 240.
  • the ring 250 in one embodiment is shaped as an equilateral triangle having an edge length L .
  • the triangle 250 is preferably positioned so that one edge is parallel to the radiating edge 220.
  • the width 1 ⁇ of the microstrip antenna 200 is greater than the edge of the ring L.. In a preferred embodiment, for a resonant frequency of 931.5 MHz, the width 1 ⁇ is approximately 40 mm.
  • the triangular ring 250 is positioned apart from the first side edge 224 by a length I ⁇ s, which is preferably equal to 11 mm.
  • the triangular ring 250 is preferably centered between side edges 224 and 226.
  • the relative position of the ring 250 within the radiating patch 216 can be varied to change the input impedence and size of the antenna.
  • the ring 250 may be offset towards the shorted edge 222 to reduce the total length of the antenna.
  • the length L A of the microstrip antenna 200 is greater than the size of the ring 250.
  • the length L A is 41.5 mm.
  • 1> ⁇ S1 and 1 ⁇ 52 are each approximately 7.5 mm in length.
  • any of these lengths can be varied to change the input impedence at the frequency of interest.
  • the ring 250 may be positioned anywhere within the radiating patch 216 subject to constraints as hereinafter explained. It is understood that varying the size and position of the ring within the patch will affect certain antenna operating characteristics, including the radiation pattern and the input impedence.
  • the thickness of the dielectric layer 214 (W D ) at the frequencies of interest is between .4 mm and 1 mm. It will be apparent to those skilled in that art that the thickness D can be increased in order to realize an increase in gain while retaining the overall size of the antenna.
  • a technique used to increase gain is to provide an exposed dielectric section 270.
  • the radiating patch 216 does not extend over this section 270.
  • the ground plane layer 212 extends to the edge 220. In previous antennas, such as the one shown in Fig.
  • the length L Q of the exposed dielectric section 270 is substantially smaller than conventional teaching would suggest. It is believed that the double ring geometry of the antenna 200 allows the length L Q to be made much smaller without any reduction in gain.
  • the length Lp is equal to 0.5 mm for an antenna designed to operate at 931.5 MHz. Conventional references suggest that this length should be substantially larger, e.g., up to 35% of the total length L A which, if followed, would require the exposed dielectric section 270 to be about 15 mm (more than 30 times larger) in the preferred embodiment.
  • the radiating patch 216 may also extend to the primary radiating edge 220, that is, Lr j may equal zero.
  • Performance testing in a laboratory has shown that the preferred embodiment of the antenna 200, while occupying a smaller space than previous antennas, is particularly resistant to human body effects and produces generally isotropic radiation patterns.
  • the electrical distance between the short circuited edge and the radiating edge is approximately equal to one quarter of the wavelength of the resonant frequency in the dielectric material.
  • the length (L A ) of the antenna from the short circuited edge 222 to the primary radiating edge 220 is less than the quarter wavelength of a given resonant frequency. It is believed that the double ring mirroring effect and the partial or fully short-circuited edge 222, as well as the triangular shape of the ring 250, operate to allow the length L A of the antenna 200 to be less than a quarter wavelength for a given resonant frequency.
  • the physical length L A of the antenna is 41.5 mm, which is approximately 40% less than any known conventional microstrip antenna with an equivalent gain.
  • the width L ⁇ is made approximately equivalent to the length L A so that an almost square structure is provided. If the width 1 ⁇ were to be made larger, gain would increase somewhat. However, it has been found that the width 1 ⁇ could be reduced below that of the length L A without a large reduction in gain.
  • the relatively square structure provides advantages including convenience in installation and a reduced size.
  • the width I-v could be made wider for more gain, but this would naturally increase the overall size of the microstrip antenna 200.
  • the width L ⁇ could be made narrower to decrease the overall size of the microstrip antenna 200, but this would reduce gain.
  • the first and second side edges 224, 226 are formed close to the edge of the ground plane and radiating patch so that the edges of the ground plane 212, the dielectric layer 214 and the radiating patch 216 are approximately flush, or evenly lined up. It is believed that when those edges are closely aligned a more isotropic radiation pattern is achieved. It has been found that the dielectric layer 214 may extend beyond the radiating patch 216 and ground plane 212 without adversely affecting the radiation pattern. However, the edges 224, 226 of the radiating patch 216 and ground plane 212 should be flush. Extending the dielectric layer 214 may be advantageous in certain installations.
  • FIG. 3 a perspective view of another specific embodiment of a double triangular ring microstrip antenna 300 is shown. This embodiment is designed to operate at 940 MHz.
  • the basic structure of the antenna is similar to the antenna shown in Fig. 2.
  • the antenna 300 includes three layers comprising a dielectric 314 sandwiched between a ground plane 312 and a radiating patch 316.
  • the dielectric is Duroid 5880 and is 0.60 mm thick.
  • the layers are substantially rectangular in shape, having a length L A and a width h ⁇ which, in a specific embodiment designed for operation at 940 MHz, are equal to 43.5 mm and 40 mm respectively.
  • the antenna 300 has four outside edges: a primary radiating edge 320; first and second side edges 324, 326; and a short circuited edge 322.
  • the short circuited edge 322 comprises a partial short circuit utilizing a length of wrapped copper foil.
  • other shorting approaches may also be utilized.
  • the antenna of Fig. 3 includes a triangular shaped aperture or ring 350 centrally positioned in the radiating patch 316.
  • the triangular shaped ring 350 exposes a portion of dielectric layer 314.
  • Antenna 300 operates in a manner similar to the operation of the antenna of Fig. 2 in that a "mirror" image of the radiating patch 316 is created relative to the short circuited edge 322. Electrically, the antenna 300 appears to be an antenna with a double triangular ring.
  • the short circuit edge 322 is a partial short circuit made of wrapped copper foil.
  • the shorted section has a length L s greater than
  • the triangular ring 350 is an equilateral triangle, having side lengths of approximately 25 mm.
  • the triangular ring 350 is positioned on the radiating patch such that one of the sides of the triangle is substantially parallel to the shorted edge 322. Satisfactory results have been attained by positioning the equilateral triangle about 11 mm from the primary radiating edge 320. It is understood that the size and relative position of the triangle may be varied in order to achieve different resonant frequencies and gains as well as to increase or decrease the input impedance of the antenna 300. For instance, the triangle may be positioned such that one edge is parallel to the primary radiating edge 320. Tests have shown that the double triangular ring antenna 300 of Fig. 3 achieves results similar to the double triangular ring antenna 200 of Fig. 2 but at a different resonant frequency.
  • a perspective view of a double diamond ring microstrip antenna 400 is shown. Again, the primary dimensions of the antenna are, preferably, similar to those given in conjunction with the discussion of Figs. 2 and 3.
  • a diamond shaped ring 450 is formed in the radiating patch 416, exposing a portion of the dielectric layer 414.
  • the diamond shaped ring 450 has a height Lr jH and a width L ⁇ , and is preferably centered between side edges 424 and 426.
  • the diamond shaped ring 450 has an edge length L ⁇ of about 16.5 mm, and a corner 451 spaced apart from the primary radiating edge 420.
  • the area of the ring 450 should be approximately the same as the area of the triangular ring 350 in order to achieve the best results.
  • Those skilled in the art will recognize that varying the size, shape, orientation and position of the diamond shaped ring 450 will affect the performance characteristics of the antenna 400.
  • Fig. 5 is a perspective view of a microstrip antenna 500 with a circular ring 550 according to the invention.
  • the external shape and dimensions of the antenna are similar to those of antennas 200, 300, and 400 of Figs. 2, 3 and 4.
  • a circular ring 550 is formed in the radiating patch 516 exposing a portion of the dielectric layer 514.
  • the circular shape of ring 550 has no straight boundaries, a center 560 and a radius R c .
  • the center is positioned midway between side edges 524 and 526, and about 20 mm from the shorted edge 522.
  • the radius R c of the circle is about 9.5 mm. Tests have shown that this embodiment of a microstrip antenna performs satisfactory when the area of the circle 550 approaches the area of the triangular ring 350.
  • Each of the double ring microstrip antennas described herein may be fabricated with an insulative solder mask which serves to insulate and protect the antenna.
  • the conductors on the antennas are covered with a thin (e.g., ⁇ l mm thick) plastic insulator that isolates the antenna from direct contact with surrounding circuit components such as batteries.
  • the solder mask also serves to protect the copper in the conductive layers from oxidizing or otherwise corroding.
  • the short circuited edge 522 comprises a partial short circuit utilizing two partially shorted sections 523 and 524. Each section has a length L S1 and L S2 , the sum of which is less than the width of the antenna 1 ⁇ by an amount L QS . Preferably, the lengths L S1 and L S2 are equal.
  • a plurality of shorting posts 560a-560d are used to short the radiating patch 516 to the ground plane 512.
  • the shorting posts are formed of a conductive material, preferably copper, and may be formed by drilling or other means well known in the art.
  • the lengths L S1 , L S2 of short circuit sections 523 and 524 are equal to about 8 mm on each side, where the overall width of the antenna L ⁇ is 40 mm.
  • the relative sizes of the shorted sections 523 and 524 may be selected to establish a selected resonant frequency and gain of the antenna.
  • two shorting posts are evenly spaced within short circuit sections 523 and 524. It has been found that the use of a greater number of shorting posts directly impacts the resonant frequency of the antenna.
  • a single partial short circuit section 523 is provided.
  • Short circuit section 523 is constructed, in one embodiment, from a wrapped section of copper sheeting which electrically connects the radiating patch 516 with the ground plane 512.
  • section 523 is about 13 mm in length when the width of the antenna (1 ⁇ ) is 40 mm, or about 1/3 the length of the edge.
  • a coaxial feed 542 is shown in each of Figs. 6A and 6B.
  • An alternative embodiment is shown in Fig. 6C, where a microstrip feed 543 is utilized in conjunction with two partial short circuit sections 523 and 524.
  • the double ring effect may be achieved utilizing any combination of the above- mentioned shorting and feed schemes. It is believed that the total length of all shorted section(s) , whether connected directly or not, must be sufficient to provide a mirror image of the radiating patch in the ground plane. Therefore, the total length of the shorted section(s) should not be reduced below that length which provides such an adequate mirror image.
  • the width of the shorted section(s) is chosen primarily to satisfy the required input impedence of 50 ohms. It has been observed that changing the width of the shorted section(s) affects the input impedence, and therefore varying the width L s as a percentage of the total width 1 * ⁇ can be useful in tuning the antenna.
  • the length L s of the short circuit is within the range of 20% to 50% of the length 1 ⁇ of the entire short circuited edge 522.
  • the currently preferred length L s is approximately 30% of 1 ⁇ .
  • a microstrip antenna 600 is shown installed within a pager 602.
  • Fig. 7 illustrates a pager 602 having a microstrip antenna 600 with a first side edge 606 facing outward.
  • the antenna 600 may be positioned in an orientation which provides the best radiation pattern, or which produces the least amount of interference with surrounding electronics.
  • the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.
  • a double ring microstrip antenna may be constructed using a full or a partial short. The short may be implemented using shorting posts or wrapped copper foil.
  • any size or shape of ring or antenna may be used. Any of the antennas developed according to the present invention may utilize a microstrip feed rather than a coaxial feed. Those skilled in the art will also appreciate the wide ability to tune the antennas of the present invention by modifying certain features such as the size or shape of the ring, or the number or placement of shorting posts. It is believed that, based upon the forgoing disclosure, those of skill in the art will now be able to produce double ring microstrip antennas having different performance characteristics by modifying the dimensions and scaling of the preferred embodiment. Further, It is apparent that the present invention may be utilized in a wide range of applications, from pagers to portable computers.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Waveguide Aerials (AREA)

Abstract

Une antenne (200) en microruban et à double anneau, présentant une taille réduite, produit des configurations de rayonnement pratiquement isotrophiques tout en subissant une baisse minimale de performance lorsqu'elle est utilisée à proximité d'autres appareils électroniques ou du corps humain. Ladite antenne (200) en microruban comporte un réseau de terre (212) et un panneau rayonnant (216), tous deux constitués de matériau conducteur, et une couche diélectrique (214) placée entre le réseau de terre (212) et le panneau rayonnant (216), lesquels forment ensemble une structure d'antenne dotée de deux bords latéraux (220, 222), un bord rayonnant principal (220) et un bord de court-circuit (222). Selon la présente invention, un court circuit le long de l'un des bords (222) provoque une réflexion qui crée une image 'miroir' du panneau rayonnant (216) par rapport au bord de court-circuit (222), ce qui engendre un effet de double anneau. Différentes formes d'anneau sont décrites.
PCT/US1995/009284 1994-07-27 1995-07-24 Antennes en microruban a double anneau WO1996003783A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU31424/95A AU3142495A (en) 1994-07-27 1995-07-24 Double ring microstrip antennas

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US28187494A 1994-07-27 1994-07-27
US08/281,874 1994-07-27

Publications (1)

Publication Number Publication Date
WO1996003783A1 true WO1996003783A1 (fr) 1996-02-08

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19606582A1 (de) * 1996-02-22 1997-10-16 Inst Mobil Und Satellitenfunkt Mobilfunk-N-Antennenvorrichtung
US7015868B2 (en) 1999-09-20 2006-03-21 Fractus, S.A. Multilevel Antennae
US10734713B2 (en) 2016-04-27 2020-08-04 Fractus Antennas, S.L. Ground plane booster antenna technology for wearable devices

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HANDBOOK OF MICROSTRIP ANTENNAS, Vol. 2, JAMES J.R. et al., LONDON, PETER PEREGRINUS LTD., 1989, pages 24-39 and 1092-1105. *
PALANISAMY et al., "Rectangular Ring and H-Shaped Microstrip Antennas--Alternatives to Rectangular Patch Antenna", 1985, pages 874-876. *

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19606582A1 (de) * 1996-02-22 1997-10-16 Inst Mobil Und Satellitenfunkt Mobilfunk-N-Antennenvorrichtung
DE19606582C2 (de) * 1996-02-22 1998-12-03 Inst Mobil Und Satellitenfunkt Mobilfunk-Antennenvorrichtung
US7015868B2 (en) 1999-09-20 2006-03-21 Fractus, S.A. Multilevel Antennae
US7123208B2 (en) 1999-09-20 2006-10-17 Fractus, S.A. Multilevel antennae
US7394432B2 (en) 1999-09-20 2008-07-01 Fractus, S.A. Multilevel antenna
US7397431B2 (en) 1999-09-20 2008-07-08 Fractus, S.A. Multilevel antennae
US7505007B2 (en) 1999-09-20 2009-03-17 Fractus, S.A. Multi-level antennae
US7528782B2 (en) 1999-09-20 2009-05-05 Fractus, S.A. Multilevel antennae
US8941541B2 (en) 1999-09-20 2015-01-27 Fractus, S.A. Multilevel antennae
US8976069B2 (en) 1999-09-20 2015-03-10 Fractus, S.A. Multilevel antennae
US9000985B2 (en) 1999-09-20 2015-04-07 Fractus, S.A. Multilevel antennae
US9054421B2 (en) 1999-09-20 2015-06-09 Fractus, S.A. Multilevel antennae
US9240632B2 (en) 1999-09-20 2016-01-19 Fractus, S.A. Multilevel antennae
US9362617B2 (en) 1999-09-20 2016-06-07 Fractus, S.A. Multilevel antennae
US9761934B2 (en) 1999-09-20 2017-09-12 Fractus, S.A. Multilevel antennae
US10056682B2 (en) 1999-09-20 2018-08-21 Fractus, S.A. Multilevel antennae
US10734713B2 (en) 2016-04-27 2020-08-04 Fractus Antennas, S.L. Ground plane booster antenna technology for wearable devices
US11705620B2 (en) 2016-04-27 2023-07-18 Ignion, S.L. Ground plane booster antenna technology for wearable devices

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