Electronic device with isolated antennas

摘要

Antennas for electronic devices are provided. First and second antennas may be mounted within an electronic device. Free-space coupling between the first and second antennas may give rise to interference. The first and second antennas may be coupled to a global ground. The global ground may be formed using a conductive member in the electronic device such as a conductive frame member. Signals that pass between the antennas through the global ground may serve as canceling signals that reduce the magnitude of free-space interference signals and thereby improve antenna isolation. The antennas may be coupled to the global ground using electrical paths or through near-field electromagnetic coupling. Coupling efficiency to the global ground may be enhanced by configuring the conductive traces of one or both of the antennas to form a resonant circuit.

主权项

1. A computer, comprising:
a plastic housing having a top and a bottom and having four sides; a metal frame member within the plastic housing, wherein the metal frame member extends along at least two of the four sides of the plastic housing; a first antenna having a first antenna resonating element and a first antenna local ground; and a second antenna having a second antenna resonating element and a second antenna local ground, wherein the metal frame member forms a global ground structure that is coupled to the first antenna and that is coupled to the second antenna, wherein the electronic device is configured such that a first version of a transmitted antenna signal from the first antenna that is received at the second antenna through the global ground structure at least partially cancels a second version of the transmitted antenna signal from the first antenna that is received by the second antenna through a free-space path to increase isolation between the first and second antennas, wherein the first antenna resonating element comprises a first planar substrate that lies in a first plane, wherein the second antenna resonating element comprises a second planar substrate that lies in a second plane, wherein the first and second planar substrates each has first, second, and third dimensions, wherein the third dimension of the first planar substrate is smaller than the first and second dimensions of the first planar substrate, wherein the third dimension of the second planar substrate is smaller than the first and second dimensions of the second planar substrate, wherein the third dimension of the first planar substrate is perpendicular to the first plane, wherein the third dimension of the second planar substrate is perpendicular to the second plane, wherein the first plane is not parallel to the second plane, wherein the first and second antennas are disposed on a given one of the four sides of the plastic housing and are between the plastic housing and the metal frame member, wherein the metal frame member is planar and lies in a third plane along the given one of the four sides of the plastic housing, wherein the third plane is parallel to the first plane, wherein the first antenna comprises conductive traces that are configured to form an L-shaped antenna resonating element and wherein the L-shaped antenna resonating element has a maximum width of between 2 mm and 5 mm and has a maximum length of between 4 mm and 8 mm.