Abstract:
An electronic device may have an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band. A tunable inductor coupled to the antenna resonating element may be used to tune the low band resonance.
Abstract:
An electronic device may be provided with a speaker box (54) antenna (40) for transmitting and receiving radio- frequency signals. A speaker box antenna may be formed from a hollow dielectric speaker box containing a speaker driver. An opening in the speaker box adjacent to the speaker driver may be aligned with a speaker port opening in a conductive electronic device housing structure. The speaker box may be surrounded by conductive structures that form a cavity for the antenna. The conductive structures may include parts of the conductive electronic device housing structure. The speaker box may have opposing upper and lower surfaces. Metal plates may form parts of the upper and lower surfaces and may be shorted together using a conductive layer such as a strip of metal tape. Frequencies of operation may be selected for the antenna that suppress undesired cavity modes and enhance antenna performance.
Abstract:
A display cover layer may be mounted in an electronic device housing using housing structures such as corner brackets. A slot antenna may be formed from a corner bracket opening, metal traces on a hollow plastic support structure, or other conductive structures. The slot antenna may have a main portion with opposing ends. An antenna feed may be located at one of the ends. The slot antenna may have a slot with one or more bends. The bends may provide the slot antenna with a C-shaped outline. A side branch slot may extend from the main portion of the slot at a location between the two bends. The presence of the side branch slot may enhance antenna bandwidth. A hollow enclosure may serve as an antenna support structure and as a speaker box enclosing a speaker driver. The antenna feed may be positioned so as to overlap the speaker driver.