Patent Application
20050057420
The present invention relates to the field of wireless communications. More specifically, the present invention relates to a low profile, sector antenna configuration.
Wireless communications are a driving force in the electronics industry. Wireless connections are widely used for computer networking, peripheral devices, and the like. Antennas are an integral part of all wireless communications. The amount of data that a wireless connection can carry, as well as the distance and the coverage of a wireless connection, often depend in large part on the size, type, and configuration of the antenna(s) being used. Larger antennas tend to provide better connectivity, but large antennas can be inconvenient, fragile, and unsightly. Furthermore, the form factors of many electronic devices do not readily accommodate large or fragile antennas.
Notebook computers provide a good example of the design challenges for antennas. Wireless networking is increasingly popular among notebook computer users. Notebook computers, however, are often compact, leaving limited room for an antenna. Durability is also quite important because notebook computers are frequently moved, packed away and pulled out of bags or carrying cases, used in cramped quarters, and the like. External housings are often made of metal to improve durability, but metal can interfere with, or shield, an antenna. This shielding effect makes an internal antenna especially difficult to implement. Attaching an antenna flush against a metal surface can also be problematic. A protruding antenna, on the other hand, can be vulnerable to damage, not to mention unsightly.
Examples of the present invention are illustrated in the accompanying drawings. The accompanying drawings, however, do not limit the scope of the present invention. Similar references in the drawings indicate similar elements.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will understand that the present invention may be practiced without these specific details, that the present invention is not limited to the depicted embodiments, and that the present invention may be practiced in a variety of alternative embodiments. In other instances, well known methods, procedures, components, and circuits have not been described in detail. Parts of the description will be presented using terminology commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. Repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may.
Embodiments of the present invention combine a strip of magnetic conductor material and a sector antenna into a low profile, sector antenna configuration that can, for example, be mounted flush on a metal surface. Various embodiments of the present invention also arrange a combination of these low profile, sector antennas in different orientations to provide improved, sectorized connectivity.
A sector antenna is directional. In other words, the radiation pattern of a sector antenna is designed to transmit and/or receive a signal in a particular direction, or orientation, with respect to the antenna. Compared to an omni-directional antenna, or a multi-directional antenna, a sector antenna can provide superior connectivity for signals within its radiation pattern.
A Yagi antenna is one example of a sector antenna.
The antenna's radiation pattern 150 is generally directed along the common axis 140, and fans out at a particular angle 160. The angle 160 is often called an azimuth or elevation, depending on how the antenna is oriented. Azimuth usually refers to the angle in a horizontal plane and elevation usually refers to the angle in a vertical plane. The azimuth and elevation angles can be different for a given antenna. In the illustrated embodiment, angle 160 is over 90 degrees.
A Yagi antenna can be made in a planar form factor with a low profile. For instance, as shown in
The magnetic conductor material used in various embodiments of the present invention is an impedance plane that acts as a sort of radio frequency mirror, both altering the direction of the radiation pattern of the sector antenna and providing improved isolation for the antenna. Artificial Magnetic Conductor (AMC) material is a type of magnetic conductor. AMC is usually made from layers of printed circuit board (PCB) material comprising metal patches, vias (holes), and dielectric material, giving it a planar form factor. In some embodiments, the AMC material can have a thickness of 4 millimeters or less.
AMC is designed to approximate a perfect magnetic conductor for signals in at least one particular frequency band. For example, single-band AMC material can approximate a perfect magnetic conductor in one frequency band, and dual-band AMC material can approximate a perfect magnetic conductor in two frequency bands.
AMC 310 alters the radiation pattern that sector antenna 320 would otherwise have. For signals in the appropriate frequency band(s) where AMC 310 approximates a perfect magnetic conductor, antenna configuration 300 has a radiation pattern 350 that is flared up at an angle 330. One or both of the fan-out angles 360 and 460 (shown in
For example, if Yagi antenna 170 from
In the illustrated embodiment, angle 330 is about 45 degrees. However, in alternate embodiments, a variety of angles may be achieved by various combinations of sector antennas and magnetic conductor materials. For example, the angle 330 may be from 35 degrees to 60 degrees in certain embodiments. In the case of a dual-band AMC strip, the radiation patterns, and the extent to which they are affected by the AMC material, may also be different for each band.
The inventive sector antenna configuration can be used in a variety of embodiments. For example,
The sector antennas can be oriented in any number of ways. For instance, an antenna mounted at a top mounting location on one edge of the notebook may be aligned so that the long axis of the antenna is parallel, or substantially parallel, to the long dimension of the edge of the notebook, with the radiation pattern angled up. The lower antenna on the same edge may also be mounted in a parallel configuration, but with the radiation pattern angled down. The antennas on the opposite side may use the same orientation. In another embodiment, the antennas may be aligned in a perpendicular, or substantially perpendicular, orientation to the long dimension of the edge of the notebook. In which case, the radiation patterns for the top sector antennas may angle toward the front, or screen, side of the lid, and the lower radiation patterns may angle to the rear side of the lid. Alternate embodiments may use any number of combinations of parallel and perpendicular orientations, with radiation patterns pointing up, down, frontward, or backward. While many sector antenna arrays can provide 360 degrees of azimuth, some embodiments may provide less than 360 degrees of azimuth. And, while edge mounting locations are often convenient to provide 360 degrees of coverage, the sector antenna configurations of the present invention can be used in any number of mounting locations.
Thus, a low profile, sector antenna is described. Whereas many alterations and modifications of the present invention will be comprehended by a person skilled in the art after having read the foregoing description, it is to be understood that the particular embodiments shown and described by way of illustration are in no way intended to be considered limiting. Therefore, references to details of particular embodiments are not intended to limit the scope of the claims.
