# US 2013/0154886 A1 · Loosely-coupled radio antenna apparatus and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154886 A1 - Document ID: US20130154886A1 - Status: Published application - Kind: A1 - Application number: 13/331,802 - Filed: 2011-12-20 - Published: 2013-06-20 - Earliest claimed: 2011-12-20 - Assignees: Pulse Finland Oy - Inventors: Anne Isohätälä - Web page: https://patentgrep.com/patent/US20130154886A1 ## CPC - H01Q 1/243: {with built-in antennas} - H01Q 5/371: Branching current paths - H01Q 5/378: Combination of fed elements with parasitic elements - H01Q 9/0421: {with a shorting wall or a shorting pin at one end of the element (H01Q9/0414 takes precedence)} - H01Q 9/045: {with particular feeding means (for circular polarisation H01Q9/0428)} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A multiband internal antenna apparatus and methods of tuning and utilizing the same. In one embodiment, the antenna configuration is used within a handheld mobile device (e.g., cellular telephone or smartphone). The device enclosure is fabricated from a conductive material and has two parts: the main portion, housing the device electronics and ground plane, and the antenna cap, which substantially envelops a directly fed radiator structure of the antenna. Electromagnetic coupling of the cap portion to the device feed effects formation of a parasitic antenna radiator in a lower frequency band. The cap portion is separated from the main portion by a narrow gap, extending along circumference of the device, and is grounded at a location selected to cause desired resonance and to widen antenna bandwidth. In one implementation, a second parasitic radiator is disposed proximate the directly feed radiator to further expand antenna frequency bands of operation. ## Claims ### Claim 1 Antenna apparatus, comprising: a loosely coupled main antenna radiator having a single feed point connection; a diversity antenna element; wherein the antenna apparatus is configured to utilize at least a portion of a metallic enclosure of a host device as a parasitic resonator; and wherein the antenna apparatus is capable of at least receiving signals in a plurality of frequency bands within both lower and upper operating frequency ranges. ### Claim 2 (depends on 1) The antenna apparatus of claim 1, wherein the antenna apparatus does not include any tuning circuitry or switches. ### Claim 3 (depends on 1) The antenna apparatus of claim 1, wherein the host device comprises a mobile cellular telephone, and the frequency bands are at least in part compliant with those specified in the Long Term Evolution (LTE) wireless standard. ### Claim 4 (depends on 1) The antenna apparatus of claim 1, wherein the antenna apparatus forms a first parasitic resonator using said main antenna radiator, and a second parasitic resonator using said diversity antenna element. ### Claim 5 A radio frequency communications device, comprising: an electronics assembly comprising a ground plane, and a feed port; at least partially electrically conductive external enclosure comprising a main portion enclosing the electronics assembly, and a first end cap enclosing a first antenna radiator having a feed structure connected to the feed port; wherein: the first antenna radiator is configured to operate in at least a first frequency band; and the first end cap is connected to the ground plane, at least at a first location, thereby forming a first parasitic radiator in a second frequency band. ### Claim 6 (depends on 5) The device of claim 5, wherein: the first antenna radiator and the first parasitic radiator form a first multiband antenna apparatus; and said first parasitic radiator is configured to widen an operating bandwidth of the first multiband antenna apparatus. ### Claim 7 (depends on 5) The communications device of claim 5, wherein said grounding of the first end cap is configured to increase radiation efficiency of the first parasitic radiator. ### Claim 8 (depends on 7) The communications device of claim 7, wherein said first end cap is disposed proximate a first end of the device. ### Claim 9 (depends on 8) The communications device of claim 8, wherein said external enclosure is fabricated from metal. ### Claim 10 (depends on 9) The communications device of claim 9, wherein said external enclosure comprises a non-conductive carrier and a conductive layer disposed thereon. ### Claim 11 (depends on 9) The communications device of claim 9, wherein: said main portion is connected to the ground plane in at least one location; and said connection of the first end cap to the ground plane is effected via the main portion. ### Claim 12 (depends on 9) The communications device of claim 9, wherein the first end cap is connected to the ground plane via a direct connection. ### Claim 13 (depends on 9) The communications device of claim 9, wherein said first end cap is separated from said main portion by a gap extending substantially around a circumference of the enclosure. ### Claim 14 (depends on 8) The communications device of claim 8, wherein: said at least partially electrically conductive enclosure further comprises a second end cap disposed proximate a second end of the device, the second end opposite the first end, the second end cap enclosing a second antenna radiator having a feed structure connected to the feed port and configured to operate in at least said first frequency band. ### Claim 15 (depends on 14) The communications device of claim 14, wherein: the second end cap is connected to the ground plane, at least at a second location, thereby forming a second parasitic radiator in said second frequency band; the second antenna radiator and the second parasitic radiator form a second multiband antenna apparatus; and said second parasitic radiator is configured to widen an operating bandwidth of the second multiband antenna apparatus. ### Claim 16 (depends on 15) The communications device of claim 15, wherein said second end cap is separated from said main portion by a second gap extending substantially around a circumference of the enclosure. ### Claim 17 A multiband antenna apparatus for use in a radio communications device having at least partially conductive external enclosure, the antenna apparatus comprising a directly fed radiator structure, having a feed portion configured to be connected to feed port of the radio communications device; wherein: said directly fed radiator structure is operable in at least a first frequency band and configured to be electromagnetically coupled to an end cap portion of the external enclosure; said end cap is electrically connected to a ground plane of the radio device via a ground structure; said grounding of the end cap is configured to widen operating bandwidth of the multiband antenna apparatus; and said enclosing of said directly fed radiator structure by said end cap and said grounding of the end cap cooperate to form a parasitically-fed radiator of the antenna apparatus in a second frequency band. ### Claim 18 (depends on 17) The antenna apparatus of claim 17, wherein said grounding of the end cap is configured to increase radiation efficiency of the multiband antenna apparatus. ### Claim 19 (depends on 17) The antenna apparatus of claim 17, wherein said second band is lower than said first band. ### Claim 20 (depends on 17) The antenna apparatus of claim 17, wherein said end cap is configured to substantially enclose the directly fed radiator structure on at least on five sides. ### Claim 21 (depends on 17) The antenna apparatus of claim 17, wherein said ground plane is spaced from said directly fed radiator structure by a predetermined ground clearance. ### Claim 22 (depends on 17) The antenna apparatus of claim 17, wherein said directly fed radiator structure comprises a first portion configured substantially parallel to said ground plane, and a second portion configured substantially perpendicular to said ground plane. ### Claim 23 (depends on 17) The antenna apparatus of claim 17, wherein the antenna comprises a parasitic radiator disposed proximate to said feed portion and configured to form an electromagnetically coupled resonance in at least a third frequency band. ### Claim 24 (depends on 23) The antenna apparatus of claim 23, wherein said second band is lower that said third band. ### Claim 25 (depends on 17) The antenna apparatus of claim 17, wherein said ground structure comprises at least a portion of a main portion of the external enclosure. ### Claim 26 (depends on 17) The antenna apparatus of claim 17, wherein said ground structure comprises a direct connection to the ground plane. ### Claim 27 A method of expanding operational bandwidth of a multiband antenna useful in a radio device having at least partially conductive external enclosure, the method comprising: energizing a first radiator structure in at least a first frequency band by effecting an electric connection between the first radiator and a feed port of the radio device; and energizing a second antenna radiator structure in at least a second frequency band by: (i) electromagnetically coupling the second radiator structure to the feed port; and (ii) effecting an electric ground connection between the second radiator structure and a ground plane of the radio device. ### Claim 28 (depends on 27) The method of claim 27, wherein said electric ground connection is effectuated via a direct connection to the ground plane. ### Claim 29 (depends on 27) The method of claim 27, wherein: said second radiator structure comprises an end cap portion of the external enclosure; and the end cap portion is connected to the ground plane, at least at a first location that is selected to widen operating bandwidth of the multiband antenna. ### Claim 30 (depends on 29) The method of claim 29, wherein said end cap portion is configured to substantially enclose the antenna apparatus at least on five sides. ### Claim 31 (depends on 29) The method of claim 29, wherein said grounding of the end cap is configured to increase radiation efficiency of the multiband antenna. ### Claim 32 An antenna radiator structure for use in a wireless device, the structure comprising: a directly fed radiating element in electrical communication with a feed structure; and a second radiating element with a slot formed therein; wherein the directly fed radiating element and said second radiating element are configured to be disposed in a substantially perpendicular orientation when installed within a host device enclosure. ### Claim 33 (depends on 32) The structure of claim 32, further comprising a parasitic element adapted for communication with a ground of the host device, the parasitic element configured for placement proximate the feed structure and to resonate at a frequency other than that of said directly fed radiating element or said second radiating element. ### Claim 34 (depends on 32) The structure of claim 32, wherein the slot is configured to create a first resonant frequency of a high frequency band associated with the structure. ### Claim 35 (depends on 34) The structure of claim 34, wherein the directly fed radiating element comprises an end portion used to tune a first harmonic of a low band resonance into the high frequency band, thus forming a second high frequency resonance.