Loosely-coupled radio antenna apparatus and methods

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.

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.

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.

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.