Traveling Wave Antenna

The personal communications wireless network infrastructure requires antennas at each end of the link whether they are outdoors or indoors. These antennas are either passive or active in nature, and are designed to meet different cell coverage needs. These antennas will either be operating at 1850 to 1990 MHz in the United States with other frequency ranges being utilized overseas.

Presently known in the art are antennas which are directed to the passive market for outdoor wireless personal communication, operating in the 1850 to 1990 MHz range. Typically, these antennas are based on a low-profile flat panel design to cover the 30, 65, 85, 90 and 105 beamwidth requirements. The antennas are vertically polarized dipoles on an etched, high performance circuit board(s) on rigid aluminum channel-like back panels. The circuit board(s) are a significant factor in the total cost of the system.

The antennas of the present invention embody a single, simply configured, flat strip radiator spaced apart and electrically isolated from a planar ground plane. Variation in radiation patterns can be effected by simply forming different angles in the strip radiators.

Broadly the invention comprises an antenna having a planar ground plane and a flat strip-like radiator shaped to radiate different beamwidths and the method of making the antenna. The strip is secured to the ground plane such that the strips lie in a plane which is substantially parallel to the ground plane.

FIG. 1 is a plan view of a 65.degree. bandwidth antenna embodying the invention;

FIG. 2 is a side view of the antenna of FIG. 1; and

FIG. 3 is a plan view of a 30.degree. beamwidth antenna embodying the invention.

Referring to FIG. 1, an antenna is shown generally at 10 and comprises a planar ground plane 12, a copper radiator 14 secured to the ground plane by plastic insulators 24. The radiator 14 is a flat strip 3/8 inch wide and 1/16 inch thick. The radiator shown is formed by bending the strip with simple tools. Power is introduced to the radiator 14 via a feed point 18. The radiator arms 20 are .lambda./2 and three inches in length. They are joined at 90.degree. angles to V-like arms 22 which are .lambda./2 and 2.75 inches from end to end (original non V-length 3.00 inches). The radiator is spaced apart 1/2 inch from the ground plane (0.125 inches thick brass sheet) by Teflon.RTM. insulators 24. The specific feed lines, connectors, radome etc. associated with the antenna need not be described in detail these considerations being within the skill of the art. Based on the foregoing specifications, a 65.degree. radiation pattern (beamwidth) will be provided at 1920 MHz.

As can readily be observed with the radiator of the invention, the length and angles of the arms can easily be formed, with a single bending tool and/or a vice and pliers. Variations in patterns (beamwidths) are achieved by forming different angles to change the spacing of the arms.

Referring to FIG. 3, a 30.degree. bandwidth antenna is shown at 40 having radiators 42 an 44 with their associated feed points 46 an 48 respectively. The radiators 42 and 44 are identical to the radiator 14 of FIG. 1. The distance D is 4.0 inches. This antenna operates at a frequency of 1920 MHz.

The foregoing description has been limited to a specific embodiment of the invention. It will be apparent, however, that variations and modifications can be made to the invention, with the attainment of some or all of the advantages of the invention. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the invention.