415 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 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.

There is provided a portable communication device for minimizing the SAR of electromagnetic waves. In the portable communication device, a slim upper housing has an FBC on which a keypad is mounted, a lower housing is vertically spaced from the slim upper housing by a predetermined distance and includes a PCB assembly, and a middle housing is positioned between the slim upper housing and the lower housing, spatially isolated from the lower housing by a separation plate to minimize the adverse effects of electromagnetic waves generated from the PCB assembly, and has a slot opened from the front end to hold an object in the lengthwise direction. A sliding battery pack is insertable to and detachable from the middle housing in the lengthwise direction.

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.

A device and a method for controlling a transmission power in a mobile terminal are provided. The device includes an antenna set in an optimized state, a memory including a power control table that includes transmission power control data for satisfying a Specific Absorption Rate (SAR) standard in a state where efficiency of the antenna is optimized, a sensor for detecting a distance between the mobile terminal and a user, a controller for receiving distance data from the sensor and for outputting transmission power control data corresponding to the distance data by referring to the power control table, and a power amplifier connected between a transmitter and the antenna for controlling transmission power of a signal according to the transmission power control data and for outputting the signal to the antenna.

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.

Systems and methods for controlling a magnetic resonance imaging system are provided. In one embodiment, a magnetic resonance imaging system includes a radio frequency coil with a plurality of conductive coil elements, control circuitry that determines, based at least in part on a measurement of scattering parameters, a plurality of forward voltages that will cause power deposition into an object within a predetermined specific absorption rate, and an amplifier configured to apply the determined plurality of forward voltages respectively to the plurality of coil elements. The control circuitry may determine the plurality of forward voltages based at least in part on an unloaded measurement of scattering parameters and a loaded measurement of scattering parameters.

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.

The present invention provides an antenna apparatus for a wireless unit, the antenna apparatus exhibiting a reduced specific absorption rate (SAR) without an additional component for reducing the SAR, which is the amount of energy of an electromagnetic wave absorbed by a human body. The antenna apparatus comprises a board 114 serving as a ground plate of an antenna, a first antenna element 102 transmitting and receiving an electromagnetic wave in a first frequency band and provided on the board 114 through the first feeder 107, and a second antenna element110 transmitting and receiving an electromagnetic wave in a second frequency band and provided on the board 114 through the first feeder 111, wherein the total of an electrical length between the first and second feeders 107 and 111, an electrical length of the first antenna element 102, and an electrical length of the second antenna element 110 is larger than a half wavelength of the first frequency band and equal to or smaller than one wavelength of the first frequency band.

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.

The invention discloses a mobile terminal and a method for reducing specific absorption rate. The mobile terminal comprises an input unit, a control unit, a memorizer, a switch, an antenna group and a radio frequency circuit. The control unit is respectively connected with the input unit, the memorizer and the switch, the antenna group comprises a plurality of antennae, and the switch is respectively connected with each antenna and the radio frequency circuit. The input unit is used for monitoring a position relative to the mobile terminal and informing the obtained position to the control unit. The memorizer is used for memorizing the corresponding information of position to specific absorption rate of each antenna. The control unit is used for searching the specific absorption rate of each antenna in obtained position through detecting from the corresponding information of the position to specific absorption rate of each antenna memorized in the memorizer, according to the obtained position through detecting of the input unit, the antenna is chosen according to the specific absorption rate of the obtained position through the detecting of each antenna, and the switch is controlled to be communicated with the antenna and the radio frequency circuit. The mobile terminal and the method for reducing the specific absorption rate are capable of reducing radiation of the mobile terminal to a human body and the head of the human body.

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 method and a device for realizing specific absorption rate (SAR) control, which are applied in a wireless terminal. In both the method and the device, metal coupling structures are arranged in different directions on the periphery of an antenna of a wireless terminal; and the metal coupling structures generate an overall director or reflector effect on near-field radiation to integrally direct the near-field radiation of the antenna to an opposite direction of a user. The method and the device do not influence the receiving and transmitting performance of a terminal, simultaneously can integrally reduce a local SAR peak, and reduce human radiation damage. In addition, the method and the device do not need to make major changes on designed and molded antennae, circuits and structures, save cost, also save space, have very high flexibility and adaptability when in application and fulfill the aim of the miniaturization design of the wireless terminal.

The invention relates to a simulation method for forest remote sensing data of a synthetic aperture radar, in particular to a quantified simulation method, belonging to the forest remote sensing technical field of the synthetic aperture radar. The simulation method comprises the following steps that: a geometrical model of a three-dimensional forest scene is built, a back scattering model of the radar is built, and SAR (Specific Absorption Rate) echo signal simulation and SAR image treatment are carried out. According to the invention, the echo signal simulation and image treatment processes are introduced in the quantified simulation process of the SAR forest remote sensing data, the overall acting process of a remote sensing system and the natural environment is reflected, and the overall link fidelity simulation from the observed object description and the action mechanism description of microwave scattering process to the acquisition of the original signal of the remote sensing system and ground image treatment can be accomplished.

Feed point (101) performs unbalanced feeding to an antenna element (102). A parasitic element (104) is provided near the antenna element (102) and a ground plane (103), approximately parallel to the width direction of the ground plane (103). Moreover, the parasitic element (104) is configured in a length to operate as a director when provided on the side of the body with respect to the ground plane (103) during talk time and in a length to operate as a reflector when provided on the opposite side from the body with respect to the ground plane (103). By this means, it is possible to improve gain and reduce the specific absorption rate (SAR) during talk time.

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.

A mobile communication terminal having an antenna and method of using the same is disclosed in which the angle of the antenna is adjusted according to a Specific Absorption Rate (SAR) value of the mobile communication terminal and a user is notified when the SAR value exceeds a predetermined value. The method stores a plurality of SAR values each corresponding to a transmission power of the mobile communication terminal in a memory and determines a current transmission power of the mobile communication terminal in a call state. The method then reads a SAR value which corresponds to the current transmission power from the memory. The angle of the antenna is then adjusted according to the SAR value.

The invention provides a unified simulation realization method of a multiple-platform multiple-mode SAR (Specific Absorption Rate) echo. The invention provides a modularized programming unified simulation realization method for SAR echo simulation under different carrying platforms and irradiation modes. By analyzing and extracting the characteristics of the SAR echo simulation under the different platforms and modes, the method divides a SAR echo simulation flow into a function program section according to functions and carries out modularized programming for the function program section to form function modules with different actions. Finally, based on systemic thought, the input and output interfaces of the function modules are unified through an application program, and a unified multiple-platform multiple-mode SAR echo simulation system is built. According to the method, three modes of echo simulation on four typical platforms of SAR are integrated, the defects of independent simulation for the SAR under the different platforms and modes in the past are overcome, and meanwhile the reliability and portability of the simulation program are improved.