Claims
- 1. An antenna for transmitting or receiving electromagnetic energy along an antenna axis, said antenna comprising:
- a driven element disposed on the antenna axis for transmission of electromagnetic energy in a transmission direction along the antenna axis; and
- first and second parasitic arrays disposed on opposite sides of the antenna axis in the transmission direction from said driven element and at least partially along a portion of the antenna axis along which parasitic elements each contribute less than half as much to the antenna directivity as does a corresponding element on one of the first and second parasitic arrays, each parasitic array having a plurality of parallel parasitic directors spaced apart along respective array lines that extend in a general direction from the driven element at a first acute angle to the transmission direction, which array lines extend, along the length of the array lines, at a maximum angle that is less than the first angle and not greater than thirty degrees, whereby the first and second parasitic arrays have a collective radiation pattern that has a lobe with greatest magnitude in the transmission direction.
- 2. An antenna according to claim 1 wherein the first and second parasitic array lines diverge from the antenna axis along their lengths.
- 3. An antenna according to claim 1 wherein each of the first and second parasitic arrays includes a distal portion that extends at an angle of less than ten degrees relative to the antenna axis.
- 4. An antenna according to claim 1 wherein each of the first and second parasitic arrays includes a distal portion that extends parallel to the antenna axis.
- 5. An antenna according to claim 1 wherein each of the first and second parasitic arrays includes a distal portion that converges toward the antenna axis.
- 6. An antenna according to claim 1 wherein the line of the antenna array includes a proximal portion that extends at the first angle and a distal portion that extends at a second angle less than the first angle.
- 7. An antenna according to claim 6 wherein the second angle is less than ten degrees.
- 8. A Yagi antenna for transmitting or receiving electromagnetic energy along an antenna axis, said antenna comprising:
- a driven element disposed on the antenna axis for transmission of electromagnetic energy in a transmission direction along the antenna axis;
- a first director parallel to said driven element and disposed adjacent to said driven element on the antenna axis in the transmission direction from said driven element,
- first and second parasitic arrays disposed on opposite sides of the antenna axis in the transmission direction from said first director, at least a portion of said first and second parasitic arrays being disposed along a portion of the antenna axis without on-axis parasitic elements, each parasitic array having a plurality of parallel parasitic directors spaced apart along respective array lines that extend in a general direction that includes a proximal portion adjacent to said first director that extends from said driven element at a first angle that is not greater than thirty degrees to the transmission direction, and a distal portion that extends at a angle that is less than the first angle and is less than ten degrees to the transmission direction, whereby said first and second parasitic arrays have a collective radiation pattern that has a lobe with greatest magnitude in the transmission direction.
- 9. An antenna according to claim 8 further comprising a second director also parallel to said driven element and disposed between the distal portions of said first and second arrays on the antenna axis.
- 10. An antenna for transmitting or receiving electromagnetic energy along an antenna axis, said antenna comprising:
- a driven element disposed on the antenna axis for transmission of electromagnetic energy in a transmission direction along the antenna axis; and
- first and second parasitic arrays disposed on opposite sides of the antenna axis in the transmission direction from said driven element and at least partially along a portion of the antenna axis along which parasitic elements each contribute less than half as much to the antenna directivity as does a corresponding element on one of the first and second parasitic arrays, each parasitic array having a plurality of parallel parasitic directors spaced apart along respective array lines and including a distal portion that extends at an angle that is less than ten degrees relative to the antenna axis, whereby the first and second parasitic arrays have a collective radiation pattern that has a lobe with greatest magnitude in the transmission direction.
Parent Case Info
This application claims the benefit of and is a continuation of U.S. application Ser. No. 08/235,490 filed on Apr. 29, 1994, now abandoned.
US Referenced Citations (14)
Continuations (1)
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Number |
Date |
Country |
Parent |
235490 |
Apr 1994 |
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