411 results about "Specific absorption rate" patented technology

A portable multimode wireless communication device (100) including first and second transmitters (110, 120) coupled to corresponding antennas or to a common antenna. The portable device controls (130) an output power of one or both of the first and second transmitters so that a characteristic, for example, the combined specific absorption rate, of the transmitters of the portable multimode wireless communication device does not exceed a specified limit.

A system and method for reducing the Specific Absorption Rate (SAR) of a mobile communication device employs a sensor assembly for sensing when the mobile communication device is in proximity to a body such as a human body, animal body, or the like. The average power of the radio frequency electromagnetic energy radiated by the mobile communication device may then be reduced only when necessary so that the SAR value for the device is maintained below a predetermined acceptable level.

An advanced antenna or set of antennae for a wireless device is provided by embedding the antennae into the battery case or generally the largest surface area of a wireless phone. The antenna connections are made through the battery's connections to the wireless device. The antenna design can be compact and located in any area of the battery. The antenna design can be thin and flat, located at the back surface of the battery or the large rear surface of a wireless phone, facing away from the user. An RF shielding device can be embedded into the battery and configured in relation to the antenna such that the RF field intensity and the consequent specific absorption rate for the user is lowered while the outgoing signals of the wireless device remain fully adequate for the function of the wireless device. This feature is preserved for a multi-band operation because a digital phase shifter is used between two radiating antennae. An external case is used as a complement to the wireless phone to provide additional antennae, power and capability.

A distributed multiband antenna intended for radio devices, and methods for designing manufacturing the same. In one embodiment, a planar inverted-F antenna (PIFA) configured to operate in a high-frequency band, and a matched monopole configured to operate in a low-frequency band, are used within a handheld mobile device (e.g., cellular telephone). The two antennas are placed on substantially opposing regions of the portable device. The use of a separate low-frequency antenna element facilitates frequency-specific antenna matching, and therefore improves the overall performance of the multiband antenna. The use of high-band PIFA reduces antenna volume, and enables a smaller device housing structure while also reducing signal losses in the high frequency band. These attributes also advantageously facilitate compliance with specific absorption rate (SAR) tests; e.g., in the immediate proximity of hand and head “phantoms” as mandated under CTIA regulations. Matching of the low-frequency band monopole antenna is further described.

Various aspects of the disclosure relate to reporting a power limit along with an indication of at least one constraint upon which the power limit is based. In some aspects, the constraint is a radio frequency (RF) exposure constraint. For example, a power headroom limit calculated by a first apparatus may be constrained by a specific absorption rate (SAR) limit or a maximum permissible exposure (MPE) limit. The first apparatus may thus report to a second apparatus the current power headroom limit of the first apparatus along with an indication of whether the power headroom limit is constrained by an SAR limit or an MPE limit (e.g., as opposed to being constrained by a maximum transmit power limit). The second apparatus may then schedule the first apparatus taking into account the power headroom limit and the corresponding constraint (e.g., maximum power or SAR/MPE).

A mobile phone capable of reducing an electromagnetic SAR in human bodies includes a base and a cover disposed on the base. The base includes an antenna for transmitting and receiving electromagnetic waves. The cover includes a screen and buttons. Electromagnetic absorbing materials having electric or magnetic loss are applied on the cover to mitigate electromagnetic waves radiating from the antenna into the user. Moreover, a meandered planar inverted-F antenna is attached to the back of the circuit board near the bottom of the base, which can generate a lower near field at the user's side than those in other directions, thereby reducing the electromagnetic specific absorption rate of the mobile phone in human bodies.

Transmission of data from a portable communication device to a base station via a radio frequency signal uses a plurality of modulation and coding schemes and a protocol that has recurring frames. Each frame has a plurality of transmission slots, different numbers of which can be used to transmit data. When it is desired to transmit data a higher rate than was used previously, an attempt is made to increase the number transmission slots being used. If doing so, produces a transmission results in a specific absorption rate limit being exceeded, then the modulation and coding scheme is changed to one having a greater data coding rate. The power level and the number transmission slots then are set so that the data transmission does not exceed the specific absorption rate limit. The data is then transmitted by the portable communication device.

The invention discloses a method, a control device and a wireless terminal for reducing the radiation hazard of the wireless terminal, belonging to the field of wireless radiation protection, wherein the method for reducing the radiation hazard of the wireless terminal comprises the following steps: using the control device to detect whether an antenna of the wireless terminal is approached by an object or not; and using the control device to adjust the output power of a wireless terminal transmitter connected with the antenna to the output protection power and reduce the specific absorption rate value of the antenna to the set value if the antenna is detected to be approached by the object. The embodiment of the invention can reduce the radiation of the wireless terminal to a human body. The technical scheme is applicable to wireless communication terminals.

An wireless communication device has a housing with an exterior surface that is designed to face a user when the wireless communication device is transmitting a radio frequency signal. The communication device includes an antenna disposed inside the housing for emitting a radio frequency signal. A metal-dielectric structure resonates to reflect the radio frequency signal. The metal-dielectric structure is located between the antenna and the exterior surface at a position wherein he metal-dielectric structure traps and reflects the radio frequency signal thereby reducing a specific absorption rate of the wireless communication device.

An inverted F antenna (IFA) which reduces specific absorption rate (SAR) includes a ground; an auxiliary radiator which is attached to one end of the ground and disposed along a plane direction of the ground; a radiator which lies at an interval from the auxiliary radiator in parallel and radiates electromagnetic waves; a feed which supplies current to the radiator; and a short which interconnects the radiator with the ground and discharges the current to the ground. Accordingly, the SAR can be decreased and the antenna size can be miniaturized.

A radio antenna apparatus is provided with an antenna connected with a radio communication circuit that transmits and receives a radio signal. A load impedance element is connected between a parasitic element of an electrical conductor plate and a ground of a housing of a radio communication apparatus including the radio communication circuit. A controller controls an element value of the load impedance element so as to set a current flowing on the housing to be equal to or smaller than a predetermined value when the radio communication apparatus transmits the radio signal, thereby controlling a specific absorption rate (SAR) to be equal to or smaller than a predetermined value.

The invention discloses a method for adjusting an electromagnetic wave energy absorption ratio based on a sensor and a mobile terminal. The mobile terminal adjusts signal transmitting power of the mobile terminal according to whether the distance which is acquired by a proximity sensor and between a human body and the mobile terminal is located in a preset distance range and/or whether a bottom side surface of the current position, acquired by a gravity sensor, of the mobile terminal is the adjacent side surface of a terminal antenna. The scheme disclosed by the invention controls the signal transmitting power of the mobile terminal according to data of the sensors, therefore, the electromagnetic wave energy absorption ratio is controlled, the problem that the human body is affected due to the fact that an SAR (specific absorption rate) value is out of limit in the prior art, and users of the mobile terminals are protected in real time.

In an apparatus for measuring a specific absorption rate (SAR) for use in a radio apparatus, a first near magnetic field of a radio wave radiated from a reference radio apparatus is measured in free space, and an SAR of the radio wave radiated from the reference radio apparatus by using a predetermined phantom according to a predetermined measurement method. A transformation factor α is calculated by dividing the measured SAR by a square value of the measured first near magnetic field, and a second near magnetic field of a radio wave radiated from a radio apparatus to be measured is measured in free space. Then an SAR of the radio wave radiated from the radio apparatus to be measured is estimated and calculated by multiplying a square value of the measured second near magnetic field by the calculated transformation factor α.

Transmission of data from a portable communication device to a station via a radio frequency signal uses a protocol that has recurring frames, each having a plurality of transmission slots, different numbers of which can be used to transmit the data. When the portable communication device desires to send a data transmission, a first value is selected for either a power level for the radio frequency signal or the number of transmission slots to use. Then the first value is used to select a second value for the other one of the power level and the number of transmission slots. The first and second values are selected so that the data transmission at the selected power level using the selected number of transmission slots does not result in a specific absorption rate that is greater than a specific absorption rate limit.

A modal antenna is proposed that provides for dynamic tuning and optimization of antenna system parameters for SAR (Specific Absorption Rate) management in mobile wireless devices. A modular approach is described where the radiator and active components are integrated into a module, allowing the fixed radiator to be used across multiple wireless products and form factors. Multiple radiation modes can be generated by a single antenna structure with one or several of the modes designed to minimize SAR while maintaining efficient communication link performance. Proximity sensors or other sensors provide indicators to determine when mode selection is necessary.

The invention discloses a specific absorption rate processing method and a mobile terminal. The method comprises that: the mobile terminal acquires a distance between a human body part of a user using the mobile terminal and the mobile terminal, and the transmitting power of the mobile terminal; the mobile terminal acquires a value of a specific absorption rate SAR according to the distance and the transmitting power; and the mobile terminal transmits a command for reducing the transmitting power and/or prompts the user under the condition that the value of the SAR is greater than a threshold value. The invention protects the user of the mobile terminal to a certain extent.