Multi-band antennas having enhanced directors therein that inhibit radiation interference across multiple frequency bands
An antenna includes a reflector, a radiating element extending forwardly of the reflector, and a director positioned forwardly of the radiating element. The director includes a plurality of passive impedance elements that provide frequency-dependent reactances to currents induced therein responsive to electromagnetic radiation generated by the radiating element. The plurality of passive impedance elements include: (i) a primary capacitive element, (ii) a first series LC circuit having a first inductor therein electrically connected to a first portion of the primary capacitive element, and (iii) a second series LC circuit having a second inductor therein electrically connected to a second portion of the primary capacitive element.
1. An antenna, comprising:
a first radiating element configured to emit first electromagnetic radiation in response to at least one feed signal having a frequency within a first radio frequency (RF) band; and
a director positioned forwardly of the first radiating element and in a path of the first electromagnetic radiation, said director comprising a plurality of passive impedance elements that provide frequency-dependent reactances to currents induced within the director in response to the first electromagnetic radiation, said plurality of passive impedance elements including a primary capacitive element, a first series LC circuit electrically coupled to a first portion of the primary capacitive element, and a second series LC circuit electrically coupled to a second portion of the primary capacitive element.
2. The antenna of claim 1 , wherein the first series LC circuit includes a first inductor electrically connected to the first portion of the primary capacitive element; and wherein the second series LC circuit includes a second inductor electrically connected to the second portion of the primary capacitive element.
3. The antenna of claim 2 , wherein a geometric center of the primary capacitive element is generally aligned to a geometric center of a forward facing surface of the first radiating element when viewed from a plan perspective.
4. The antenna of claim 3 , wherein the primary capacitive element is rectangular shaped; wherein the first portion of the primary capacitive element extends adjacent a first corner of the primary capacitive element; and wherein the second portion of the primary capacitive element extends adjacent a second corner of the primary capacitive element.
5. The antenna of claim 3 , wherein the primary capacitive element is square shaped; wherein a capacitive element within the first series LC circuit is rectangular shaped; and wherein a capacitive element within the second series LC circuit is rectangular shaped.
6. The antenna of claim 2 , wherein a geometric center of a capacitive element within the first series LC circuit extends in a first direction relative to a geometric center of the primary capacitive element; and wherein a geometric center of a capacitive element within the second series LC circuit extends in a second direction relative to the geometric center of the primary capacitive element.
7. The antenna of claim 6 , wherein the first and second directions are generally perpendicular to each other when viewed from a plan perspective.
8. The antenna of claim 6 , wherein the first and second directions are generally opposing directions when viewed from a plan perspective.
9. The antenna of claim 2 , wherein said plurality of passive impedance elements include a third series LC circuit electrically coupled to a third portion of the primary capacitive element.
10. The antenna of claim 9 , wherein said plurality of passive impedance elements include a fourth series LC circuit electrically coupled to a fourth portion of the primary capacitive element.
11. The antenna of claim 10 , wherein the primary capacitive element is rectangular shaped; and wherein the first, second, third and fourth portions of the primary capacitive element correspond to first, second, third and fourth sides thereof, respectively.
12. The antenna of claim 2 , wherein the primary capacitive element is rectangular shaped; wherein the first portion of the primary capacitive element extends adjacent a first corner of the primary capacitive element; and wherein the second portion of the primary capacitive element extends adjacent a second corner of the primary capacitive element.
13. The antenna of claim 2 , wherein a capacitive element within the first series LC circuit has a greater area relative to an area of the primary capacitive element.
14. The antenna of claim 13 , wherein a capacitive element within the second series LC circuit has an area equivalent to an area of the capacitive element within the first series LC circuit.
15. The antenna of claim 1 , further comprising:
a reflector;
a first array of radiating elements extending in a lengthwise direction along a first side of the reflector;
a second array of radiating elements extending in a lengthwise direction along a second side of the reflector; and
a third array radiating elements extending in a lengthwise direction across the reflector, and between the first and second arrays of radiating elements;
wherein the radiating elements in the first and second arrays are configured as the first radiating element; and
wherein the director is within an array of directors extending forwardly of the radiating elements within the first array.
16. An antenna, comprising:
a reflector;
a radiating element extending forwardly of the reflector; and
a director positioned forwardly of the radiating element, said director comprising a plurality of passive impedance elements that provide frequency-dependent reactances to currents induced therein responsive to electromagnetic radiation generated by said radiating element, said plurality of passive impedance elements including a primary capacitive element, a first series LC circuit having a first inductor therein electrically connected to a first portion of the primary capacitive element, and a second series LC circuit having a second inductor therein electrically connected to a second portion of the primary capacitive element.
17. The antenna of claim 16 , wherein a geometric center of the primary capacitive element is generally aligned to a geometric center of a forward facing surface of the radiating element when viewed from a plan perspective.
18. The antenna of claim 17 ,
wherein a geometric center of a capacitive element within the first series LC circuit extends in a first direction relative to the geometric center of the primary capacitive element;
wherein a geometric center of a capacitive element within the second series LC circuit extends in a second direction relative to the geometric center of the primary capacitive element; and
wherein the first and second directions are generally perpendicular to each other when viewed from the plan perspective.
19. The antenna of claim 16 , wherein an area of a capacitive element within the first series LC circuit is greater than an area of the primary capacitive element.
20. The antenna of claim 16 , wherein said plurality of passive impedance elements further include: (i) a third series LC circuit electrically coupled to a third portion of the primary capacitive element; and (ii) a fourth series LC circuit electrically coupled to a fourth portion of the primary capacitive element.