Chassis-excited antenna apparatus and methods
View Patent ↗A chassis-excited antenna apparatus, and methods of tuning and utilizing the same. In one embodiment, a distributed loop antenna configuration is used within a handheld mobile device (e.g., cellular telephone). The antenna comprises two radiating elements: one configured to operate in a high-frequency band, and the other in a low-frequency band. The two antenna elements are disposed on different side surfaces of the metal chassis of the portable device; e.g., on the opposing sides of the device enclosure. Each antenna component comprises a radiator and an insulating cover. The radiator is coupled to a device feed via a feed conductor and a ground point. A portion of the feed conductor is disposed with the radiator to facilitate forming of the coupled loop resonator structure.
1. An antenna component for use in a portable communications device, the device comprising a ground, a feed port, and a metal structure having a plurality of sides, said component comprising:
a radiator element having a first dimension and a second dimension, a first and second surface, and configured to be disposed proximate to a first side of said plurality of sides;
a dielectric substrate having a third dimension and a fourth dimension, and configured to be disposed proximate the second surface;
a feed conductor configured to couple to the radiator element at a feed point; and
a dielectric element disposed between the radiator element and the first side and configured to electrically isolate at least a portion of the first side from the radiator element.
2. The antenna component of claim 1 , wherein:
a normal projection of the dielectric substrate is equal or larger than a normal projection of the radiator element; and
the radiator element is electrically coupled to the ground at a ground point.
3. The antenna component of claim 2 , wherein
at least a portion of the feed conductor is arranged along the first side substantially parallel to the first dimension; and
the radiator element, the at least a portion of the feed conductor, and at least a portion of the first side form a coupled loop antenna operable in a first frequency band.
4. The antenna component of claim 1 , wherein the radiator element comprises a conductive structure comprising a first portion and a second portion, wherein the second portion is coupled to the feed point via a reactive circuit.
5. The antenna component of claim 4 , further comprising a dielectric element disposed between the radiator element and the first side and configured to electrically isolate at least a portion of the first side from the radiator element.
6. The antenna component of claim 4 , wherein the reactive circuit comprises a planar transmission line.
7. The antenna component of claim 4 , wherein the second portion further comprises a second reactive circuit, configured to adjust electrical size of the radiator element.
8. The antenna component of claim 7 , wherein the second reactive circuit comprises at least one of (i) an inductive element, and/or (ii) a capacitive element.
9. The antenna of claim 4 , wherein
the radiator element comprises a dielectric substrate, and a conductive coating disposed thereon; and
the conductive structure comprises the conductive coating.
10. The antenna component of claim 1 , wherein
the metal structure comprises a sleeve like shape having at least a first cavity; and
the first side comprises a metal support element disposed within the first cavity.
11. The antenna component of claim 1 , wherein
at least a portion of the feed conductor is arranged along the first side substantially parallel to the first dimension; and
the radiator element, the at least a portion of the feed conductor, and at least a portion of the first side form a coupled loop antenna operable in a first frequency band.
12. The antenna of claim 1 , wherein the radiator element comprises a dielectric substrate, and a conductive coating disposed thereon.
13. The antenna of claim 1 , wherein the radiator element comprises a flex circuit.
14. An antenna apparatus for use in a portable communications device comprising a metal enclosure having a plurality of sides and housing an electronics comprising a ground and at least one feed port, said antenna apparatus comprising:
a first antenna assembly configured to operate in a first frequency band, the first assembly comprising:
a first radiator element comprising a first ground point and a first feed point, and disposed along a first of the plurality of sides;
a first feed conductor coupled to the first feed point and to the at least one feed port; and
a first non-conductive cover disposed proximate the first radiator so as to substantially cover the first radiator; and
a second antenna assembly configured to operate in a second frequency band, the second assembly comprising:
a second radiator element comprising a second ground point and a second feed point, disposed along a second of the plurality of sides;
a second feed conductor coupled to the second feed point and to a feed port; and
a second non-conductive cover disposed proximate the second radiator so as to substantially cover the second radiator;
wherein the first of the plurality of sides is arranged substantially opposite from the second of the plurality of sides.
15. The antenna apparatus of claim 14 , wherein:
the metal enclosure is electrically coupled to the ground, to the first ground point, and to the second ground point;
at least a portion of a first feed cable is disposed along the first side thereby forming a first coupled loop antenna structure between at least a portion of the metal enclosure, the first radiator element, and the at least a portion of the first feed cable; and
at least a portion of a second feed cable is disposed along the second side thereby forming a second coupled loop antenna structure between at least a portion of the metal enclosure, the second radiator element, and the at least a portion of the second feed cable.
16. The antenna apparatus of claim 15 , wherein the first and second radiator elements are disposed substantially between the first and second covers, respectively, and the metal enclosure.
17. The antenna apparatus of claim 16 , further comprising a dielectric element disposed between the radiator element and the first side and configured to electrically isolate at least a portion of the first side from the radiator element.
18. The antenna apparatus of claim 14 , wherein the first and second radiator elements are disposed substantially between the first and second covers, respectively, and the metal enclosure.
19. The antenna of claim 14 , wherein the first frequency band comprises a frequency band between 700 and 960 MHz and the second frequency band comprised an upper frequency band.
20. The antenna of claim 19 , wherein the upper frequency band comprises frequency band between 1710 and 2150 MHz.
21. The antenna of claim 19 , wherein the upper frequency band comprises a global positioning system (GPS) frequency band.
22. The antenna of claim 14 , wherein the feed port comprises the at least one feed port.
23. The antenna apparatus of claim 14 , wherein
the metal enclosure comprises a sleeve like shape having a first cavity and a second cavity; and
the first side comprises a first metal support element disposed within the first cavity and configured to receive the first radiator element; and
the second side comprises a second metal support element disposed within the second cavity and configured to receive the second radiator element.
24. An antenna component comprising:
a dielectric substrate having a plurality of surfaces;
a conductive coating disposed on at least one surface of the substrate, the conductive coating configured to form:
at least a portion of a ground plane, comprising a ground point;
a radiator structure comprising:
a feed;
a first portion;
a second portion;
a stripline coupled from said second portion to said feed point; and
a plurality of non conductive slots isolating substantially separating the strip line from the first portion; and
at least one ground clearance area disposed substantially within perimeter of the a t least one surface;
wherein the ground point is configured to couple the at least a portion of the ground plane to a ground of a host device; and
wherein the second portion is coupled to the first portion via a conductive element.
25. The antenna component of claim 24 , wherein the second portion is further coupled to the first portion via a reactive circuit.
26. The antenna component of claim 25 , wherein the reactive circuit comprises at least one of (i) an inductive element, and/or (ii) a capacitive element.
27. A mobile communications device, comprising:
a substantially metallic exterior housing comprising a plurality of sides;
an electronics assembly contained substantially therein and comprising a ground and at least one feed port;
a first antenna assembly configured to operate in a first frequency band, the first assembly comprising:
a first radiator element comprising a first ground point and a first feed point, and disposed along a first of the plurality of sides;
a first feed conductor coupled to the first feed point and to the at least one feed port; and
a first non-conductive cover disposed proximate the first radiator so as to substantially cover the first radiator; and
a second antenna assembly configured to operate in a second frequency band, the second assembly comprising:
a second radiator element comprising a second ground point and a second feed point, disposed along a second of the plurality of sides;
a second feed conductor coupled to the second feed point and to a feed port; and
a second non-conductive cover disposed proximate the second radiator so as to substantially cover the second radiator;
wherein:
the first ground point and the second ground point are electrically coupled to the metal housing;
a first coupled loop resonance structure is formed between at least a portion of the housing, the first radiator, and at least a portion of the first feed cable; and
a second coupled loop resonance structure is formed between at least a portion of the housing, the second radiator, and at least a portion of the second feed cable.