WO1996038874A1 - Printed antenna having electrical length greater than physical length - Google Patents

Printed antenna having electrical length greater than physical length Download PDF

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Publication number
WO1996038874A1
WO1996038874A1 PCT/US1996/008056 US9608056W WO9638874A1 WO 1996038874 A1 WO1996038874 A1 WO 1996038874A1 US 9608056 W US9608056 W US 9608056W WO 9638874 A1 WO9638874 A1 WO 9638874A1
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WO
WIPO (PCT)
Prior art keywords
circuit board
conductive trace
printed
printed circuit
printed antenna
Prior art date
Application number
PCT/US1996/008056
Other languages
French (fr)
Inventor
Gerard J. Hayes
Ross W. Lampe
Original Assignee
Ericsson Inc.
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 Ericsson Inc. filed Critical Ericsson Inc.
Priority to AU59553/96A priority Critical patent/AU5955396A/en
Publication of WO1996038874A1 publication Critical patent/WO1996038874A1/en

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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
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support

Definitions

  • the present invention relates to printed antennas for radiating and receiving electromagnetic signals and, more particularly to a printed antenna having a radiating element in the form of a conductive trace formed on a printed circuit board where the electrical length of the conductive trace is greater tha its physical length.
  • a monopole antenna mounted perpendicularly to a conductive surface provides an antenna having good radiation characteristics, desirable drive point impedance, and relatively simple construction. Consequently, such monopole antennas have been utilized with portable radios, cellular telephones, and other communication equipment. While the present invention is also applicable to a dipole antenna, the monopole antenna is smaller in size and may be viewed as an asymmetric dipole antenna in which the monopole radiating element is one element and a radio case or the like is the other element. Because reduction in size is a desirable characteristic, certain monopole designs, such as the helical configuration disclosed in U.S. Patent 5,231,412 to Eberhardt et al. , have been used. By doing so, the physical length of the radiating element is significantly less than a corresponding straight wire radiator, but exhibits the same effective electrical length.
  • helical radiating elements are effective for reducing the size of wire radiating elements, it has been found that such designs reduce the operating radiation bandwidth of an antenna due to changes in the input impedance over frequency. This reduction in bandwidth results from the combination of lower radiation resistance due to smaller antenna size and of a larger amount of stored energy, causing a high Q and a low radiation bandwidth. While measures have been taken to expand the bandwidth of such helical radiating elements, such as including a coaxial sleeve therearound, this has had the adverse effect of increasing the overall size of the antenna. Further, it is difficult to construct such helical radiating elements, whether with a sleeve or not, within strict tolerance requirements.
  • Microstrip and lamina antennas have also been developed for use with certain communication applications with the goal of minimizing size requirements and permitting multi-band operation. More specifically, U.S. Patent 4,475,107 to Makimoto et al. discloses a circularly polarized microstrip line antenna in which the conductor consists of a plurality of crank-type fundamental elements, U.S. Patent 4,459,593 to Hall et al. discloses a strip line antenna array of the type in which the strip turns through successive right angle corners to form successive four-cornered cells, and U.S. Patent 5,262,791 to Tsuda et al. discloses a multi-layer array antenna including a plurality of microstrip antennas formed on a dielectric substrate having square wave-type patterns.
  • each of these antenna configurations include conductors which are of a non ⁇ linear type, it is understood that each one requires a transverse electric and magnetic field (TEM field) in order to operate. Because a TEM wave cannot exist without a ground plane, it will be understood that these type of antennas are able to radiate due to the aperture created by the separation of the conducting elements and the ground plane.
  • U.S. Patent 5,363,114 to Shoemaker discloses a planar serpentine antenna which includes a generally flat, non-conductive carrier layer and a generally flat radiator of a preselected length arranged in a generally serpentine pattern secured to the surface of the carrier layer.
  • This antenna has a sinuous pattern with radiator sections in parallel spaced relation in order to provide dual frequency band operation.
  • other configurations include a non ⁇ linear or serpentine pattern in order to minimize size requirements.
  • a printed antenna in light of the foregoing, it would be desirable for a printed antenna to be developed which is able to minimize the physical length for a desired electrical length, while simultaneously improving the electrical current distribution thereof. Further, it would be desirable for a printed antenna to be developed which minimizes the physical length of its radiating elements for a desired electrical length without substantially increasing the energy stored therein and making it more susceptible to external conditions.
  • a primary object of the present invention is to provide a printed antenna which minimizes the physical length of its conductive traces for a desired electrical length.
  • Another object of the present invention is to provide a printed antenna having a radiating element with a pattern which increases self inductance per unit length and thereby increases the electrical length thereof.
  • Still another object of the present invention is to provide a printed antenna which minimizes the overall size thereof.
  • Yet another object of the present invention is to provide a printed antenna which minimizes the physical length of its radiating element without substantially increasing the energy stored therein, thereby making it less susceptible to external conditions.
  • Another object of the present invention is to provide a printed antenna which minimizes the physical length of the radiating element and simultaneously improves the radiation efficiency thereof.
  • Still another object of the present invention is to provide a printed antenna which is operable within more than one frequency band with a plurality of radiating elements having substantially equivalent physical lengths.
  • a printed antenna including a printed circuit board of a specified length and width having a first side and a second side.
  • a radiating element in the form of a conductive trace is formed on one of the printed circuit board sides, with the conductive trace having a physical length from a first end to a second end where an electrical length of the conductive trace is greater than the physical length thereof.
  • At least a portion of the conductive trace has a non-linear pattern which preferably is in the form of a repeating crank or square wave pattern.
  • a printed antenna having a substantially planar printed circuit board of a specified length and width having a first side and a second side, with the printed circuit board including a center axis therethrough.
  • a radiating element in the form of a continuous conductive trace is formed on the first and second printed circuit board sides, with the conductive trace having a physical length from a first end to a second end and an electrical length greater than the physical length thereof.
  • the continuity of the conductive trace is accomplished by either extending the conductive trace around the side edges of the printed circuit board or passing the conductive trace therethrough by means of vias.
  • the conductive trace is made up of a plurality of segments on the first and second sides of the printed circuit board, with the segments extending at least partially at an angle to or parallel with the center axis on at least one of the circuit board sides in order to continue from a feed end to an open end.
  • Fig. 1 is a schematic left side view of a printed monopole antenna having a radiating element in accordance with the present invention
  • Fig. 2 is an enlarged, partial schematic view of the conductive trace forming the radiating element in Fig. 1, where the conductive trace has been rotated 90 * for ease of viewing and description;
  • Fig. 3A-3D are enlarged, schematic views of alternative conductive trace patterns which could be utilized with the printed monopole antenna of Fig. 1;
  • Fig. 4 is a schematic left side view of a printed monopole antenna having a radiating element in accordance with the present invention formed on both -6- sides of the printed circuit board;
  • Fig. 5 is a schematic right side view of the printed monopole antenna of Fig. 4;
  • Fig. 6 is a schematic left side view of a printed monopole antenna having an alternative radiating element configuration formed on both sides of the printed circuit board;
  • Fig. 7 is a schematic right side view of the printed monopole antenna of Fig. 6.
  • Fig. 1 depicts a printed monopole antenna 10 of the type which can be utilized with radio transceivers, cellular telephones, and other personal communication equipment having a single frequency band of operation.
  • printed monopole antenna 10 includes a printed circuit board 12, which preferably is planar in configuration and has a first side 14 (see Figs. 1, 4 and 6) and a second side 16 (see Figs. 5 and 7).
  • printed monopole antenna 10 includes a monopole radiating element in the form of a conductive trace 18 formed on at least first side 14 of printed circuit board 12.
  • conductive trace 18 is shown as being formed only on side 14 of printed circuit board 12 in Fig. 1, it will be seen in Figs. 5 and 7 that conductive trace 18 may also be formed on second side 16 as well.
  • conductive trace 18 has a physical length l from a feed end 22 to an opposite open end 24. It will be seen in Fig. 1 that physical length 1_ of conductive trace 18 will be substantially the physical length of printed circuit board 12, with printed circuit board 12 also having generally a width x . As seen in Fig. 1, at least a portion of conductive trace 18 is non-linear, as designated by the numeral 26. In this manner, conductive trace 18 is able to have an electrical length greater than physical length l x . Of course, it will be noted that conductive trace 18 may entirely be non-linear in its design or in fact have a non-linear portion anywhere along printed circuit board first side 14.
  • conductive trace 18 has a pattern enabling a greater electrical length than its physical length, it will also be recognized that this pattern increases the self inductance per unit length of conductive trace 18 and thereby is able to increase the electrical length thereof.
  • conductive trace 18 preferably has a pitch 28, or separation between adjacent crank elements 30, which increases the self capacitance per unit length thereof so that the electrical length of conductive trace is increased thereby as well. Accordingly, by optimizing the mutual coupling effect between crank elements 30, conductive trace 18 is able to adjust the electric current distribution of printed antenna 10. This modified electric current distribution better approximates the radiation resistance for conductive trace 18 instead of a sinusoidal current distribution normally utilized, which has the effect of improving the radiation efficiency of conductive trace 18.
  • non-linear portion 26 of conductive trace 18 is depicted in order to better identify crank elements 30 and pitch 28 therebetween.
  • the length of pitch 28 is less than 10% of a wavelength corresponding to an operating frequency for conductive trace 18.
  • Fig. 2 has a repeating crank pattern in which the length 1 4 of pitch 28 is substantially equivalent to a width w 2 of each crank 30.
  • Fig. 2 shows pitch 28 and width w 2 of crank 30 as being substantially constant, Figs.
  • each crank 30 is made up of a first crank member 32 extending from a first end to a second end transversely away from a center axis 34 running through printed circuit board 12 (see Fig. 1) .
  • a second crank member 36 is connected at a first end to a second end of first member 32 and extends generally parallel to center axis 34.
  • a third crank member 38 is then connected at a first end to a second end of second member 36 and extends transversely toward center axis 34.
  • a fourth crank member is then connected at a first end to a second end of third crank member 38 and extends generally along center axis 34 to a first end of a first member for an adjacent crank 30.
  • first crank member 32, second crank member 36, third crank member 38, and fourth crank member 40 all have a substantially equivalent length as indicated by length 1 2 , 1 3 , and 1 4 . It is possible that the various lengths of crank members 32, 36, 38 and 40 may be varied in any number of ways, with first and third crank members 32 and 38 preferably having substantially equivalent lengths (see 1 2 ) as shown also in Figs. 3A-3D. This is because first and third crank members 32 and 38 will generally have a length substantially equal to width w x of printed circuit board 12 to maximize the effect of the present invention. However, second and fourth crank members 36 and 40 may be either substantially equivalent as shown in Fig.
  • first and third crank members 32 and 38 may be either greater or less than second and fourth crank members 36 and 40 depending upon design requirements.
  • a second embodiment for printed monopole antenna 10 involves a continuous conductive trace 42 which is formed on both first side 14 and second side 16 of printed circuit board 12. In this way, the electrical length is able to be maximized for a given physical length of printed circuit board 12. This is accomplished either by extending conductive trace 42 around the sides of printed circuit board 12 as shown in Figs. 4 and 5 or permitting conductive trace 42 to extend through printed circuit board 12 by means of a plurality of vias 44 as shown in Figs. 6 and 7. As seen in Figs. 4-7, conductive trace 42 comprises a plurality of segments 46 and 48 formed on first side 14 and second side 16, respectively, of printed circuit board 12. Segments 46 and 48 together comprise the total conductive trace 42.
  • At least one adjacent segment 46 or 48 must extend at least partially either parallel or at an angle to center axis 34 so that conductive trace 42 is able generally to continue from feed end 22 to open end 24.
  • segments 46 and 48 may take any number of different shapes or configurations as shown by the examples in Figs. 4-7.
  • conductive traces 18 and 42 have an electrical length which may be substantially greater than the physical length thereof.
  • conductive trace 18 may be at least twice as great as its physical length and conductive trace 42 may be at least four times as great as its physical length.

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Abstract

A printed antenna (10) is disclosed including a printed circuit board (12) of a specified length and width having a first side (14) and a second side. A radiating element in the form of a conductive trace (18) is formed on one of the printed circuit board sides, with the conductive trace having a physical length from a first end to a second end where an electrical length of the conductive trace is greater than the physical length thereof. The conductive trace has at least a portion with a non-linear pattern (26), which preferably is in the form of a repeating crank or square wave pattern.

Description

PRINTED ANTENNA HAVING ELECTRICAL LENGTH GREATER THAN PHYSICAL LENGTH
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to printed antennas for radiating and receiving electromagnetic signals and, more particularly to a printed antenna having a radiating element in the form of a conductive trace formed on a printed circuit board where the electrical length of the conductive trace is greater tha its physical length.
2. Description of the Related Art
It has been found that a monopole antenna mounted perpendicularly to a conductive surface provides an antenna having good radiation characteristics, desirable drive point impedance, and relatively simple construction. Consequently, such monopole antennas have been utilized with portable radios, cellular telephones, and other communication equipment. While the present invention is also applicable to a dipole antenna, the monopole antenna is smaller in size and may be viewed as an asymmetric dipole antenna in which the monopole radiating element is one element and a radio case or the like is the other element. Because reduction in size is a desirable characteristic, certain monopole designs, such as the helical configuration disclosed in U.S. Patent 5,231,412 to Eberhardt et al. , have been used. By doing so, the physical length of the radiating element is significantly less than a corresponding straight wire radiator, but exhibits the same effective electrical length.
Although helical radiating elements are effective for reducing the size of wire radiating elements, it has been found that such designs reduce the operating radiation bandwidth of an antenna due to changes in the input impedance over frequency. This reduction in bandwidth results from the combination of lower radiation resistance due to smaller antenna size and of a larger amount of stored energy, causing a high Q and a low radiation bandwidth. While measures have been taken to expand the bandwidth of such helical radiating elements, such as including a coaxial sleeve therearound, this has had the adverse effect of increasing the overall size of the antenna. Further, it is difficult to construct such helical radiating elements, whether with a sleeve or not, within strict tolerance requirements.
Microstrip and lamina antennas have also been developed for use with certain communication applications with the goal of minimizing size requirements and permitting multi-band operation. More specifically, U.S. Patent 4,475,107 to Makimoto et al. discloses a circularly polarized microstrip line antenna in which the conductor consists of a plurality of crank-type fundamental elements, U.S. Patent 4,459,593 to Hall et al. discloses a strip line antenna array of the type in which the strip turns through successive right angle corners to form successive four-cornered cells, and U.S. Patent 5,262,791 to Tsuda et al. discloses a multi-layer array antenna including a plurality of microstrip antennas formed on a dielectric substrate having square wave-type patterns. While each of these antenna configurations include conductors which are of a non¬ linear type, it is understood that each one requires a transverse electric and magnetic field (TEM field) in order to operate. Because a TEM wave cannot exist without a ground plane, it will be understood that these type of antennas are able to radiate due to the aperture created by the separation of the conducting elements and the ground plane. Further, U.S. Patent 5,363,114 to Shoemaker discloses a planar serpentine antenna which includes a generally flat, non-conductive carrier layer and a generally flat radiator of a preselected length arranged in a generally serpentine pattern secured to the surface of the carrier layer. One form of this antenna has a sinuous pattern with radiator sections in parallel spaced relation in order to provide dual frequency band operation. Moreover, other configurations include a non¬ linear or serpentine pattern in order to minimize size requirements. Once again, while this design may be effective for reducing the physical length of the radiating element, it does not alter the electric current distribution therethrough.
Accordingly, in light of the foregoing, it would be desirable for a printed antenna to be developed which is able to minimize the physical length for a desired electrical length, while simultaneously improving the electrical current distribution thereof. Further, it would be desirable for a printed antenna to be developed which minimizes the physical length of its radiating elements for a desired electrical length without substantially increasing the energy stored therein and making it more susceptible to external conditions.
In light of the foregoing, a primary object of the present invention is to provide a printed antenna which minimizes the physical length of its conductive traces for a desired electrical length.
Another object of the present invention is to provide a printed antenna having a radiating element with a pattern which increases self inductance per unit length and thereby increases the electrical length thereof.
Still another object of the present invention is to provide a printed antenna which minimizes the overall size thereof.
Yet another object of the present invention is to provide a printed antenna which minimizes the physical length of its radiating element without substantially increasing the energy stored therein, thereby making it less susceptible to external conditions.
Another object of the present invention is to provide a printed antenna which minimizes the physical length of the radiating element and simultaneously improves the radiation efficiency thereof.
Still another object of the present invention is to provide a printed antenna which is operable within more than one frequency band with a plurality of radiating elements having substantially equivalent physical lengths.
These objects and other features of the present invention will become more readily apparent upon reference to the following description when taken in conjunction with the following drawing.
SUMMARY OF THE INVENTION In accordance with one aspect of the present invention, a printed antenna is disclosed including a printed circuit board of a specified length and width having a first side and a second side. A radiating element in the form of a conductive trace is formed on one of the printed circuit board sides, with the conductive trace having a physical length from a first end to a second end where an electrical length of the conductive trace is greater than the physical length thereof. At least a portion of the conductive trace has a non-linear pattern which preferably is in the form of a repeating crank or square wave pattern.
In accordance with a second aspect of the present invention, a printed antenna is disclosed having a substantially planar printed circuit board of a specified length and width having a first side and a second side, with the printed circuit board including a center axis therethrough. A radiating element in the form of a continuous conductive trace is formed on the first and second printed circuit board sides, with the conductive trace having a physical length from a first end to a second end and an electrical length greater than the physical length thereof. The continuity of the conductive trace is accomplished by either extending the conductive trace around the side edges of the printed circuit board or passing the conductive trace therethrough by means of vias. The conductive trace is made up of a plurality of segments on the first and second sides of the printed circuit board, with the segments extending at least partially at an angle to or parallel with the center axis on at least one of the circuit board sides in order to continue from a feed end to an open end.
BRIEF DESCRIPTION OF THE DRAWING
While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the same will be better understood from the following description taken in conjunction with the accompanying drawing in which:
Fig. 1 is a schematic left side view of a printed monopole antenna having a radiating element in accordance with the present invention;
Fig. 2 is an enlarged, partial schematic view of the conductive trace forming the radiating element in Fig. 1, where the conductive trace has been rotated 90* for ease of viewing and description;
Fig. 3A-3D are enlarged, schematic views of alternative conductive trace patterns which could be utilized with the printed monopole antenna of Fig. 1;
Fig. 4 is a schematic left side view of a printed monopole antenna having a radiating element in accordance with the present invention formed on both -6- sides of the printed circuit board;
Fig. 5 is a schematic right side view of the printed monopole antenna of Fig. 4;
Fig. 6 is a schematic left side view of a printed monopole antenna having an alternative radiating element configuration formed on both sides of the printed circuit board; and
Fig. 7 is a schematic right side view of the printed monopole antenna of Fig. 6.
DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in detail, wherein identical numerals indicate the same elements through the figures, Fig. 1 depicts a printed monopole antenna 10 of the type which can be utilized with radio transceivers, cellular telephones, and other personal communication equipment having a single frequency band of operation. As seen therein, printed monopole antenna 10 includes a printed circuit board 12, which preferably is planar in configuration and has a first side 14 (see Figs. 1, 4 and 6) and a second side 16 (see Figs. 5 and 7). It will be noted that printed monopole antenna 10 includes a monopole radiating element in the form of a conductive trace 18 formed on at least first side 14 of printed circuit board 12. Although conductive trace 18 is shown as being formed only on side 14 of printed circuit board 12 in Fig. 1, it will be seen in Figs. 5 and 7 that conductive trace 18 may also be formed on second side 16 as well.
More specifically, it will be seen that conductive trace 18 has a physical length l from a feed end 22 to an opposite open end 24. It will be seen in Fig. 1 that physical length 1_ of conductive trace 18 will be substantially the physical length of printed circuit board 12, with printed circuit board 12 also having generally a width x. As seen in Fig. 1, at least a portion of conductive trace 18 is non-linear, as designated by the numeral 26. In this manner, conductive trace 18 is able to have an electrical length greater than physical length lx . Of course, it will be noted that conductive trace 18 may entirely be non-linear in its design or in fact have a non-linear portion anywhere along printed circuit board first side 14. Moreover, while conductive trace 18 has a pattern enabling a greater electrical length than its physical length, it will also be recognized that this pattern increases the self inductance per unit length of conductive trace 18 and thereby is able to increase the electrical length thereof. In addition, conductive trace 18 preferably has a pitch 28, or separation between adjacent crank elements 30, which increases the self capacitance per unit length thereof so that the electrical length of conductive trace is increased thereby as well. Accordingly, by optimizing the mutual coupling effect between crank elements 30, conductive trace 18 is able to adjust the electric current distribution of printed antenna 10. This modified electric current distribution better approximates the radiation resistance for conductive trace 18 instead of a sinusoidal current distribution normally utilized, which has the effect of improving the radiation efficiency of conductive trace 18.
As seen in Fig. 2, non-linear portion 26 of conductive trace 18 is depicted in order to better identify crank elements 30 and pitch 28 therebetween. As added self capacitance per unit length of conductive trace 18 and is identified in Fig. 2 as having a length 14. Preferably, the length of pitch 28 is less than 10% of a wavelength corresponding to an operating frequency for conductive trace 18. With regard to the specific pattern of conductive trace 18 it will be seen that Fig. 2 has a repeating crank pattern in which the length 14 of pitch 28 is substantially equivalent to a width w2 of each crank 30. Of course, while Fig. 2 shows pitch 28 and width w2 of crank 30 as being substantially constant, Figs. 3A-3D depict alternative embodiments of a non¬ linear pattern for conductive trace 18 in which length 14 of pitch 28 and/or width w2 of cranks 30 is not uniform thereacross. It will be also noted that each crank 30 is made up of a first crank member 32 extending from a first end to a second end transversely away from a center axis 34 running through printed circuit board 12 (see Fig. 1) . A second crank member 36 is connected at a first end to a second end of first member 32 and extends generally parallel to center axis 34. A third crank member 38 is then connected at a first end to a second end of second member 36 and extends transversely toward center axis 34. A fourth crank member is then connected at a first end to a second end of third crank member 38 and extends generally along center axis 34 to a first end of a first member for an adjacent crank 30.
As seen in Fig. 2, first crank member 32, second crank member 36, third crank member 38, and fourth crank member 40 all have a substantially equivalent length as indicated by length 12, 13, and 14. It is possible that the various lengths of crank members 32, 36, 38 and 40 may be varied in any number of ways, with first and third crank members 32 and 38 preferably having substantially equivalent lengths (see 12) as shown also in Figs. 3A-3D. This is because first and third crank members 32 and 38 will generally have a length substantially equal to width wx of printed circuit board 12 to maximize the effect of the present invention. However, second and fourth crank members 36 and 40 may be either substantially equivalent as shown in Fig. 2 or one of the elements may be greater than the other, such as shown in Fig. 3B (where fourth crank element 40 is greater than second crank element 36) . Moreover, first and third crank members 32 and 38 may be either greater or less than second and fourth crank members 36 and 40 depending upon design requirements.
A second embodiment for printed monopole antenna 10 involves a continuous conductive trace 42 which is formed on both first side 14 and second side 16 of printed circuit board 12. In this way, the electrical length is able to be maximized for a given physical length of printed circuit board 12. This is accomplished either by extending conductive trace 42 around the sides of printed circuit board 12 as shown in Figs. 4 and 5 or permitting conductive trace 42 to extend through printed circuit board 12 by means of a plurality of vias 44 as shown in Figs. 6 and 7. As seen in Figs. 4-7, conductive trace 42 comprises a plurality of segments 46 and 48 formed on first side 14 and second side 16, respectively, of printed circuit board 12. Segments 46 and 48 together comprise the total conductive trace 42. At least one adjacent segment 46 or 48 must extend at least partially either parallel or at an angle to center axis 34 so that conductive trace 42 is able generally to continue from feed end 22 to open end 24. Of course, segments 46 and 48 may take any number of different shapes or configurations as shown by the examples in Figs. 4-7.
It will be understood that conductive traces 18 and 42 have an electrical length which may be substantially greater than the physical length thereof. For example, depending upon width wx of printed circuit board 12, conductive trace 18 may be at least twice as great as its physical length and conductive trace 42 may be at least four times as great as its physical length.
Having shown and described the preferred embodiment of the present invention, further adaptations of the printed antenna and a conductive trace utilized as the radiating element therefor can be accomplished by modifications by one of ordinary skill in the art without departing from the scope of the invention. In particular, it will be understood that while the invention was shown and described with regard to a monopole-type antenna, it could just as easily be utilized with a dipole-type antenna. What is claimed is:

Claims

1. A printed antenna, comprising:
(a) a printed circuit board of a specified length and width having a first side and a second side; and
(b) a radiating element comprising a conductive trace formed on one of said printed circuit board sides, said conductive trace having a physical length from a first end to a second end, wherein an electrical length of said conductive trace is greater than said physical length of said conductive trace.
2. The printed antenna of claim 1, wherein at least a portion of said conductive trace is non-linear.
3. The printed antenna of claim 1, wherein said conductive trace has a repeating crank pattern.
4. The printed antenna of claim 3, wherein said conductive trace has a specified distance between adjacent cranks.
5. The printed antenna of claim 4, wherein said specified distance is substantially less than a wavelength corresponding to an operating frequency for said radiating element.
6. The printed antenna of claim 4, wherein said, specified distance is substantially equivalent to a width for each said crank.
7. The printed antenna of claim 4, wherein said specified distance is greater than a width for each said cran .
8. The printed antenna of claim 1, wherein said conductive trace lies substantially in a single plane.
9 . The printed antenna of claim 1, wherein said printed circuit board is substantially planar.
10. The printed antenna of claim 1, wherein said electrical length of said conductive trace is at least approximately twice said physical length of said conductive trace.
11. The printed antenna of claim 3, each of said crank elements further comprising:
(a) a first member extending from a first end to a second end transversely away from a linear axis through said conductive trace;
(b) a second member connected at a first end to said second end of said first member extending parallel to said linear axis;
(c) a third member connected at a first end to a second end of said second member extending transversely toward said linear axis; and
(d) a fourth member connected at a first end to a second end of said third member extending along said linear axis.
12. The printed antenna of claim 11, wherein said first, second, third and fourth members have a substantially equivalent length.
13. The printed antenna of claim 11, wherein said first and third members have a substantially equivalent length.
14. The printed antenna of claim 11, wherein said second and fourth members have a substantially equivalent length.
15. The printed antenna of claim 13, wherein said first and third members have a greater length than said second and fourth members.
16. The printed antenna of claim 11, wherein said fourth element has a greater length than said second element.
17. The printed antenna of claim 3, wherein the distance between adjacent cranks is uniform.
18. The printed antenna of claim 3, wherein the distance between adjacent cranks is not uniform.
19. The printed antenna of claim 11, wherein said first and third members have a length equal to or less than a width of said printed circuit board.
20. The printed antenna of claim 11, wherein the length of said second element for each of said cranks is substantially equivalent.
21. The printed antenna of claim 11, wherein the length of said second element for each of said crank is nonuniform.
22. The printed antenna of claim 1, wherein said printed antenna is a monopole.
23. The printed antenna of claim 1, wherein said printed antenna is a dipole.
24. A printed antenna, comprising:
(a) a substantially planar printed circuit board of a specified length and width having a first side and a second side, said printed circuit board including a center axis therethrough;
(b) a radiating element comprising a continuous conductive trace formed on said printed circuit board first and second sides, said conductive trace having a physical length from a first end to a second end, wherein an electrical length of said conductive trace is greater than said physical length of said conductive trace.
25. The printed antenna of claim 24, further comprising a plurality of vias in said printed circuit board, wherein said conductive trace formed on one of said printed circuit board sides passes through said printed circuit board and is formed on said other printed circuit board side.
26. The printed antenna of claim 24, wherein said conductive trace is formed on one of said printed circuit board sides, extends to and around a first side edge of said printed circuit board, is formed on said other printed circuit board side, and continues to and around a second edge of said printed circuit board in repeating fashion.
27. The printed antenna of claim 25, wherein said conductive trace comprises a plurality of sections formed on said first and second sides of said printed circuit board, wherein said sections formed on at least one of said printed circuit board sides includes at least one segment extending generally parallel to said center axis.
28. The printed antenna of claim 26, wherein said conductive trace comprises a plurality of sections formed on said first and second sides of said printed circuit board, wherein said sections formed on at least one of said printed circuit board sides includes at least one segment extending generally parallel to said center axis.
29. The printed antenna of claim 25, wherein said conductive trace comprises a plurality of sections formed on said first and second sides of said printed circuit board, wherein said sections formed on at least one of said printed circuit board sides extends at least partially at an angle to said center axis.
30. The printed antenna of claim 26, wherein said conductive trace comprises a plurality of sections formed on said first and second sides of said printed circuit board, wherein said sections formed on at least one of said printed circuit board sides extends at least partially at an angle to said center axis.
PCT/US1996/008056 1995-06-02 1996-05-30 Printed antenna having electrical length greater than physical length WO1996038874A1 (en)

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US08/459,959 1995-06-02

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WO2001017061A1 (en) * 1999-09-01 2001-03-08 Siemens Aktiengesellschaft Multiband antenna
DE19923524C1 (en) * 1999-05-21 2001-04-19 Siemens Ag Antenna, for mobile transmitters/receivers working with different frequencies, comprises two body sections with mounting and geometric surface structures using injection molding and surface coating
WO2009014554A1 (en) * 2007-07-24 2009-01-29 Sony Ericsson Mobile Communications Ab Printed circuit boards with a multi-plane antenna and methods for configuring the same

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Cited By (4)

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Publication number Priority date Publication date Assignee Title
DE19923524C1 (en) * 1999-05-21 2001-04-19 Siemens Ag Antenna, for mobile transmitters/receivers working with different frequencies, comprises two body sections with mounting and geometric surface structures using injection molding and surface coating
WO2001017061A1 (en) * 1999-09-01 2001-03-08 Siemens Aktiengesellschaft Multiband antenna
WO2009014554A1 (en) * 2007-07-24 2009-01-29 Sony Ericsson Mobile Communications Ab Printed circuit boards with a multi-plane antenna and methods for configuring the same
US7724193B2 (en) 2007-07-24 2010-05-25 Sony Ericsson Mobile Communications Ab Printed circuit boards with a multi-plane antenna and methods for configuring the same

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