Variable aspect ratio tapered slot antenna for increased directivity and gain

A Variable Aspect Ratio Tapered Slot Antenna For Increased Directivity And Gain (NC#98102). The apparatus includes a tapered slot antenna having a length and a height, and having an aspect ratio greater than or equal to 2.5. The tapered slot antenna includes a first antenna element comprising conductive material and configured to receive and transmit RF signals; and a second antenna element comprising conductive material, operatively coupled to said first antenna element, configured to receive and transmit RF signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. Pat. No. 7,009,572, issued on Mar. 7, 2006, entitled “Tapered Slot Antenna”, by Rob Horner et al., Navy Case No. 96507, which is hereby incorporated by reference in its entirety herein for its teachings on antennas. This application is also related to U.S. Ser. No. 10/932,646 filed on Aug. 31, 2004, entitled “Concave Tapered Slot Antenna”, by Rob Horner et al., Navy Case No. 96109, which is hereby incorporated by reference in its entirety herein for its teachings on antennas.

BACKGROUND OF THE INVENTION

The present invention is generally in the field of antennas.

Typical tapered slot antennas have average directivity and gain.FIG. 1Ais a side view of a typical tapered slot antenna (TSA). As shown inFIG. 1A, TSA100includes an antenna pair (i.e., antenna element110and antenna element120) comprising conductive material. The antenna pair of TSA100has gap height194, a feed end and a launch end. The feed end of the antenna pair corresponds to the portion of the antenna pair that is proximate to axis140(represented by dashed line K-K onFIG. 1A). The feed end receives and transmits signals. The launch end of the antenna pair corresponds to the portion of the antenna pair that is proximate to axis146(represented by dashed line N-N onFIG. 1A). Note that the launch end only denotes a location on the antenna pair versus an actual launch point of a particular frequency. Antenna element (AE)110has lateral edge114, which corresponds to the portion of AE110that is proximate to axis142(represented by dashed line L-L onFIG. 1A). Antenna element120has lateral edge124, which corresponds to the portion of AE120that is proximate to axis144(represented by dashed line M-M onFIG. 1A).

Typical TSA have an aspect ratio (i.e., length to height ratio) that is equal to 1. TSA length154of TSA100is defined as the distance between the feed end (proximate to axis140) and the launch end (proximate to axis146). TSA height162of TSA100is defined as the distance between the lateral edges of the antenna pair (i.e., the distance between lateral edge114and lateral edge124) (i.e., the distance between axis142and axis144). Thus, the aspect ratio of TSA100(i.e., ratio between TSA length154and TSA height162) is equal to 1.

FIG. 1Bis a front view of one embodiment of a typical TSA. TSA100ofFIG. 1Bis substantially similar to TSA100ofFIG. 1A, and thus, similar components are not described again in detail hereinbelow. As shown inFIG. 1B, TSA100includes an antenna pair (i.e., antenna element110, antenna element120). The antenna pair of TSA100has gap height194. TSA100has TSA width172.

A need exists for tapered slot antennas having increased directivity and gain.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to Variable Aspect Ratio Tapered Slot Antenna For Increased Directivity And Gain.

Definitions

The following acronyms and definitions are used herein:

VAR—Variable Aspect Ratio

Aspect ratio—the ratio between the length and height of a TSA

The variable aspect ratio (VAR) tapered slot antenna for increased directivity and gain includes a TSA having an aspect ratio greater than or equal to 2.5. The VAR TSA for increased directivity and gain includes an antenna pair.

FIG. 2Ais a side view of one embodiment of a variable aspect ratio tapered slot antenna for increased directivity and gain. As shown inFIG. 2A, VAR TSA for increased directivity and gain200includes an antenna pair (i.e., antenna element210and antenna element220) comprising conductive material. The antenna pair of VAR TSA for increased directivity and gain200has gap height294, a feed end and a launch end. The feed end of the antenna pair corresponds to the portion of the antenna pair that is proximate to axis240(represented by dashed line K-K onFIG. 2A). The feed end receives and transmits signals. The launch end of the antenna pair corresponds to the portion of the antenna pair that is proximate to axis246(represented by dashed line N-N onFIG. 2A). Note that the launch end only denotes a location on the antenna pair versus an actual launch point of a particular frequency. The feed end can be operatively coupled to an input/output (I/O) feed such as a coaxial cable. An I/O feed can be used to transmit and receive RF signals to and from VAR TSA for increased directivity and gain200. RF signals can be transmitted from the feed end toward the launch end, wherein the RF signals launch from the antenna pair at a point between the feed end and the launch end depending on the signal frequency. Antenna element210has lateral edge214, which corresponds to the portion of AE210that is proximate to axis242(represented by dashed line L-L onFIG. 2A). Antenna element220has lateral edge224, which corresponds to the portion of AE220that is proximate to axis244(represented by dashed line M-M onFIG. 2A).

In one embodiment, TSA antenna elements210,220have curvatures that can each be represented by the following Equation 1:
Y(x)=a(ebx31 1)  (Equation 1);

where, a and b are parameters selected to produce a desired curvature. In one embodiment, parameters “a” and “b” are approximately equal to 0.2801 and 0.1028, respectively.

VAR TSA for increased directivity and gain200has an aspect ratio (i.e., length to height ratio) that is greater than or equal to 2.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 3. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 3.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 4. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 4.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 5.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 6. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 6.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 7. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 7.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 8. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 8.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 9. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 9.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 10. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 10.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 11. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 11.5. In one embodiment, VAR TSA for increased directivity and gain200has an aspect ratio greater than or equal to 12. TSA length254of VAR TSA for increased directivity and gain200is defined as the distance between the feed end (proximate to axis240) and the launch end (proximate to axis246). TSA height262of VAR TSA for increased directivity and gain200is defined as the distance between the lateral edges of the antenna pair (i.e., the distance between lateral edge214and lateral edge224) (i.e., the distance between axis242and axis244). Thus, the aspect ratio of VAR TSA for increased directivity and gain200(i.e., ratio between TSA length254and TSA height262) is greater than or equal to 2.5. In one embodiment, TSA length254equals 2.5 feet and TSA height equals 1 foot. In one embodiment, TSA length254equals 5 feet and TSA height equals 2 feet.

FIG. 2Bis a front view of one embodiment of a VAR TSA for increased directivity and gain. VAR TSA for increased directivity and gain200ofFIG. 2Bis substantially similar to VAR TSA for increased directivity and gain200ofFIG. 2A, and thus, similar components are not described again in detail hereinbelow. As shown inFIG. 2B, VAR TSA for increased directivity and gain200includes an antenna pair (i.e., antenna element210, antenna element220). The antenna pair of VAR TSA for increased directivity and gain200has gap height294. VAR TSA for increased directivity and gain200has TSA width272.

The VAR is the ratio of the overall antenna length254(which is equal to the antenna element length) over the overall antenna height262(which is equal to the combined maximum heights of both antenna elements plus the distance of gap height294between the two antenna elements, as shown inFIGS. 2A and 2B). In addition to increasing the VAR as described above, the VAR can selectively manipulated by varying the ratio of overall length254to overall height262. For example, selectively decreasing the VAR by decreasing overall length254(or by increasing overall height262) will result in a TSA with decreased directivity and gain, but with an extended lower frequency response. In this manner, many different applications can be achieved by varying the overall length254and overall height262of the ISA, provided the antenna elements have the curvature described above.

FIG. 3is a flowchart illustrating an exemplary process to implement an exemplary VAR TSA for increased directivity and gain. While boxes310through330shown in flowchart300are sufficient to describe one embodiment of an exemplary TSACA, other embodiments of the TSACA may utilize procedures different from those shown in flowchart300.