SUPERIMPOSED MULTIMODE ANTENNA FOR ENHANCED SYSTEM FILTERING

摘要

The disclosure concerns a method of designing antennas to reduce the amount of rejection and complexity from the filter system. A superposition of a symmetrical frequency response from the antenna structure coupled with a non-symmetrical frequency response from a counterpoise structure generates increased rejection of out-of-band components.

主权项

1. A method for improved filtering in an antenna system of a wireless communication device, the method comprising in any order:
(i) providing a modal antenna including:
an antenna radiating element positioned above a ground plane forming an antenna volume therebetween;a first parasitic element positioned adjacent to the antenna radiating element; anda first active tuning element coupled to the first parasitic element and further coupled to a ground reference, the first active tuning element being configured to vary a reactive load on the parasitic element or control a connection to the ground reference;the modal antenna being configurable about a plurality of possible antenna modes by varying a tuning state of the first active tuning element coupled to the first parasitic element; wherein the modal antenna is configured to produce a distinct radiation pattern in each of said plurality of antenna modes; (ii) configuring the antenna radiating element to produce a first frequency response including at least one first resonance spanning a first band of the modal antenna, wherein the first frequency response further includes a first roll-off associated with a first end of the first band and a second roll-off associated with a second end of the first band; and (iii) configuring the first parasitic element to provide a second frequency response of the modal antenna, wherein the second frequency response includes the at least one first resonance spanning the first band and further includes an adjusted roll-off associated one of the first and second ends of the first band, the adjusted roll-off being sharper than the corresponding first or second roll-off; wherein the sharper adjusted roll-off of the second frequency response provides improved filtering of RF signals.