Patent Application
20080198084
1. Field
The technology of the present application relates generally to dipole antennas, and more specifically to asymmetrical dipole antennas.
2. Background
Omni directional antennas are useful for a variety of wireless communication devices because the radiation pattern allows for good transmission and reception from a mobile unit. Currently, printed circuit board omni directional antennas are not widely used because of various drawbacks in the antenna device. In particular, cable power feeds to conventional omni directional antennas tend to alter the antenna impedance and radiation pattern, which reduces the benefits of having the omni directional antenna.
One useful antenna provides a omni direction antenna having a radiating portion and a power dissipation portion. A power source feed is coupled to the radiating portion to provide RF power to the radiating elements. A power source ground is coupled to the power dissipation portion. The power dissipation portion tends to reduce the influence the power feed has on the radiation pattern of the omni directional antenna.
Another useful antenna provides a dual band single center feed dipole antenna. The dipole is loaded by providing open circuit arms or stubs that form a second dipole that resonates at a second frequency.
Still, however, there is a need in the industry for improved compact wideband omni directional antennas.
To attain the advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an omni directional antenna is provided. The antenna includes a plurality of conductive traces on a substrate (flexible or rigid). One conductive trace comprises the radiating portion and includes a plurality of radiating arms asymmetrically arranged. The other conductive trace comprises the ground portion and includes a plurality of ground arms. Radio frequency power is supply using, for example, a coaxial cable feed. The outer conductor of the coaxial cable feed is attached ground portion (either substantially parallel or perpendicular to a portion of the ground arms. The central conductor of the cable traverses a gap between the radiating portion and ground portion and is coupled to the radiating portion distal from the radiating arms.
The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention, and together with the description, serve to explain the principles thereof. Like items in the drawings may be referred to using the same numerical reference.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, any embodiment described herein should be considered exemplary unless otherwise specifically noted. The technology of the present invention is specifically described with respect to a multiple band dipole antenna comprising two radiating arms and three ground arms. One of ordinary skill in the art will recognize on regarding the disclosure, however, other constructions and configurations are possible.
Referring first to
Antenna 100 can be separated into a radiating portion 106 and a ground portion 108. Radiating portion 106 comprises conductive traces 102 arranged with a plurality of radiating arms 110 extending from a radiating portion base 112. Radiating portion base 112 has a first base end 112f and a second base end 112s with a base body 112b extending therebetween. The plurality of radiating arms 110 extend asymmetrically from radiating base 112. While placement specifically depends on a number of conventional factors, in this case, one radiating arm 110o extend from first base end 112f along a first end an edge 114 of substrate 104 forming a gap, slot, space, or recess 116 about another radiating arm 110a. The radiating arm 110a extends from base body 112b between the first base end 112f and the second base end 112s into gap 116. Radiating arm 110o has a first shape A and radiating arm 110a has a second shape B. First shape A and second shape B are shown as different, but could be the same.
Ground portion 108 comprises conductive traces 102 arranged with a plurality of ground arms 120. Ground portion includes a ground portion base 122 having a first ground end 122f and a second ground end 122s with a ground body 122b extending therebetween. While placement specifically depends on a number of conventional factors, in this case, a first ground arm 120f extends from the first ground end and wraps around a second ground arm 120s such that a gap, slot, space, or recess 124 exists. A third ground arm 120t extends from second ground end 122s along an edge 126 opposite edge 114. While shown offset, another radiating arm 110a and second ground arm 120s may be opposite each other. First ground arm 120f has a shape C. Second ground arm 120s has a shape D. Third ground arm 120t has a shape E. While shown as different, the shapes C, D, and E could be the same (see
Radio frequency power is supply by a power feed 130. Power feed 130 is shown as a coaxial cable feed, but could be other conventional radio frequency power sources. Power feed 130 has a ground portion 132 and a conductor portion 134. Conductor portion 134 extends over gap 300 separating radiating portion 106 and ground portion 108 and is connected to radiating portion base 112 proximate second base end 112s to supply radio frequency power to radiating portion 106. Ground portion 132 is connected to third ground arm 120t along edge 126. As can be appreciated, power feed 130 extends along third ground arm 120t.
While other configurations are possible with more or less radiating arms and ground arms, antenna 100 provides two radiating arms and three ground arms providing antenna 100 the ability to resonate at multiple frequencies. The arrangement of the arms, including the extension of some arms into gaps provide enhanced coupling.
Third ground arm 120t when aligned with power feed 130 may be considered a feed arm. Ground portion 132 may be connected to third ground arm 120 using any conventional means, but for a coaxial power feed as shown a solder connection is satisfactory. When soldered, the ground portion should be soldered at least in two locations to inhibit the movement of power feed 130.
Referring now to
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The present Application for Patent is related to the following co-pending U.S. patent applications and issued patents: U.S. patent application Ser. No. 11/217,760, titled Multi-band omni directional antenna, filed Sep. 1, 2005, which is a continuation of U.S. patent application Ser. No. 10/708,520, titled Multi-band omni directional antenna, filed Mar. 9, 2004, now U.S. Pat. No. 6,943,731, the disclosures of which are incorporated herein by reference as if set out in full; and U.S. Pat. No. 6,791,506, titled Dual band single feed dipole antenna and method of making the same, filed Oct. 23, 2002, the disclosure of which is incorporated herein by reference as if set out in full.
