ADJUSTABLE MULTIBAND ANTENNA AND METHODS
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Accused Products
Abstract
An adjustable multiband antenna especially intended to mobile terminals. The antenna structure comprises a radiator (320), a feed element (330) and an adjusting circuit (350). The radiator is a conductive part of the outer cover (COV) of a radio device or conductive coating of the cover. It is fed electromagnetically by a feed element which is isolated from the radiator by a relatively thin dielectric substrate. The feed element is connected either directly or through an intermediate element (340) to the antenna port of the device and to the ground plane (310), and it is shaped so that the antenna has at least two operating bands. The adjusting circuit is connected to an adjusting point (AP) in the feed element, and the reactance between the adjusting point and ground and thus the electric size of the antenna can be changed by means of a switch (SW) in the adjusting circuit. Among other things, the component values of the adjusting circuit and the distance between the short-circuit (SP) and adjusting (AP) points in the feed element are variables from the point of view of the antenna adjustment. Displacements, which have desired directions and lengths, are obtained for at least two operation bands of the antenna independently from each other by changing the switch state. The efficiency of the antenna is better than of the corresponding known antennas, and its matching can be made good both in lower and upper operating band of the antenna.
60 Citations
40 Claims
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1-8. -8. (canceled)
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9. A multiband antenna for use in a radio device capable of operating in at least a first frequency band and a second frequency band, said antenna comprising:
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a feed element, comprising; a feed point coupled to a feed port of the radio device; a short-circuit point coupled to a ground plane; and an adjusting point; a radiating element comprising a conductive portion capable of being disposed on a cover of the radio device; an adjusting circuit coupled to the adjusting point and configured to effect a predetermined frequency shift in at least one of the first and second operating frequency bands, the adjusting circuit comprising; a multi-way switch; and at least two reactive circuits coupled to the ground plane and being selectable by the switch; wherein the conductive portion is isolated from the feed element by a dielectric substrate thereby effecting electromagnetic coupling between the radiating element and the feed element; wherein the feed element is shaped so as to at least partly induce a resonance in the first or second operating frequency bands during operation; and wherein an electric length between the adjusting point and the short-circuit point is based at least in part on the predetermined frequency shift.
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10. A planar antenna assembly operable in at least a first frequency band and a second frequency band, the assembly comprising:
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a dielectric substrate comprising a first surface; a feed element, disposed at least partly on the first surface and comprising; a feed point, configured to couple to a feed port; a short-circuit point configured to couple to a ground plane; and an adjusting point; and a radiating element; wherein the adjusting point is disposed within the feed element. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A portable radio device operable in at least a first frequency band and a second frequency band, the portable radio device comprising:
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a cover; an electronics assembly comprised of a ground plane, control logic, and a transceiver having a feed port; and a multiband antenna, comprising; a dielectric substrate comprising a first surface; a feed element, disposed at least partly on the first surface and comprising; a feed point coupled to the feed port; a short-circuit point coupled to the ground plane; and an adjusting point; and a radiating element disposed on the cover; wherein the dielectric substrate is configured to isolate the radiating element from the feed element, thereby effecting electromagnetic coupling between the radiating element and the feed element. - View Dependent Claims (28, 29, 30)
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31. An adjustable antenna having at least a lower operating band and an upper operating band and comprising:
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a ground plane; a radiating element; a feed element capable of being connected to an antenna port of a radio device; and an adjusting circuit; wherein the radiating element comprises either;
(1) a conductive part of an outer cover of the radio device;
or (2) a conductor coating of the cover, and is galvanically isolated from the feed element by a substrate such that there is only an electromagnetic coupling between the radiating element and the feed element. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. An adjustable antenna having at least a lower and an upper operating band and comprising a ground plane, a radiating element, a feed element to be connected to an antenna port of a radio device and an adjusting circuit, which radiating element is a conductive part of an outer cover of the radio device or of conductor coating of the cover and is galvanically isolated from the feed element by a substrate, in which case there is only an electromagnetic coupling between the radiating element and the feed element, which feed element comprises a short-circuit point (SP) connected to the ground plane and is shaped so that it has together with other parts of the antenna a resonance frequency both in lower and upper operating band, which adjusting circuit comprises, to displace at least one operating band of the antenna, a multi-way switch (SW) and at least two alternative reactive circuits connected to the ground plane at their one end, characterized in that the feed element comprises an adjusting point (AP), the adjusting circuit then being connected between this adjusting point and the ground plane, and an electric distance in the feed element between the AP and the SP being arranged for displacement of the operating bands with a desired length.
Specification