Wireless local area network antenna system and method of use therefore

#The present invention generally relates to electronically beam steering phased array antennas, tunable phase shifter, and tunable dielectric capacitors.

#Multipath delay causes the information symbols represented in an 802.11 signal to overlap, which confuses the receiver. This is often referred to as intersymbol Interference (ISI). Because the shape of the signal conveys the information being transmitted, the receiver will make mistakes when demodulating the signal's information. If the delays are great enough, bit errors in the packet will occur. The receiver won't be able to distinguish the symbols and interpret the corresponding bits correctly.

#When multipath strikes in this way, the receiving station will detect the errors through 802.11's error checking process. The CRC (cyclic redundancy check) checksum will not compute correctly, indicating that there are errors in the packet. In response to bit errors, the receiving station will not send an ACK to the source. The source will then eventually retransmit the signal after regaining access to the medium.

#The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

#FIG. 1 is an illustration of one embodiment of the antenna system of the present invention;

#FIG. 2 is an illustration of another embodiment of the antenna system of the present invention;

#It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements.

#Although tunable materials in general can be utilized and are anticipated by the present invention, one tunable material that is described in an embodiment of the present invention is Parascan®. Parascan® is a trademarked tunable dielectric material developed by Paratek Microwave, Inc., the assignee of the present invention. Tunable dielectric materials are the materials whose permittivity (more commonly called dielectric constant) can be varied by varying the strength of an electric field to which the materials are subjected or immersed. Examples of such materials can be found in U.S. Pat. Nos. 5,312,790, 5,427,988, 5,486,491, 5,693,429 and 6,514,895. These materials show low dielectric loss and high tunability. Tunability is defined as the fractional change in the dielectric constant with applied voltage. The patents above are incorporated into the present application by reference in their entirety. Parascan® voltage tunable dielectric materials are embodied within software controlled tunable filters, diplexers, matching networks and phased-array antennas, tunable notch filters, null-steer antennas, smart antennas, tunable phase shifters, voltage controlled oscillators (VCO's) and voltage tunable dielectric capacitors. The terms Parascan® voltage tunable capacitors, Parascan® variable capacitors, Parascan® tunable dielectric capacitors and Parascan® varactors have the same meaning and are interchangeable herein. The exemplary embodiments can include an electronically tunable dielectric material comprising; at least one electronically tunable dielectric phase comprising barium strontium titanate; and at least one metal silicate phase comprising a silicate of at least one metal selected from Be, Mg, Ca, Sr, Ba, Ra, Li, Na, K, Rb, Cs, Al, Zr, Zn, Fr, B, Fe, Mn, Cu, Ce, Cr, La, Y, Ti, Ta, Nb, Mo, W, Ni, Pd, Pb and Bi, wherein the metal silicate comprise from about 5 to about 65 weight percent of material.

#Existing antenna configurations for wireless networks may utilize an antenna configuration that is based on multiple fixed beams. For example, there may be 13 independent beams that support three simultaneous packets on three different channels. The 10 other unused beams when not in “listening” or “scanning” mode may be used solely to detect new user access requests. Since the beams are narrow, multipath problems may be reduced to some extent, but since the sidelobes or the slope of the main beam can still detect multipath signals, it is not eliminated completely. If the number of beams is reduced, for example, and not by way of limitation, from 13 to 4, the multipath negative effects may be reduced. However, with a reduced number of beams, the number of users that can be covered efficiently may also be reduced. Another concern for the existing system is that the 3.8 dB crossover or scalloping loss typical in multiple adjacent fixed beams may cause capacity and throughput reduction. Yet another concern for the existing systems is that if the users decide to move around inside the coverage range, they will face even more degraded quality of service.