Abstract: A radio frequency (RF) device includes an RF transceiver, an RF antenna, and a magnetic signal detector. The RF is selected to be in the very high frequency (VHF), ultrahigh frequency (UHF), or super high frequency (SHF) bands such that the shielding effect is reduced and the RF device can be configured as a SIM card disposed inside a cellular phone with an increased RF communication range. The magnetic signal detector is used to sense a magnetic field signal from an RF reader, which includes an RF transceiver, an RF antenna, and a magnetic signal transmitter. The longer communication range afforded by the VHF, UHF, or SHF bands is reduced by the sensing of the magnetic field, thereby providing a communication range control, while the RF device and the RF reader exchange information through the RF channel with improved security as a result of the range control.

Abstract: This invention discloses a system and method for indoor positioning of a mobile terminal. The system comprises a control end and at least one positioning node installed indoors. The at least one positioning node, under the control of the control end, transmits linkage information to the mobile terminal within a specific zone, receives response information responded by the mobile terminal, measures signal strength of the response information, and transmits the received response and signal strength information to the control end. The control end analyzes and calculates on the received response and signal strength information to locate the mobile terminal. Using this invention, a user can realize accurate positioning of an indoor mobile terminal without changing existing mobile terminals. The disclosed positioning system and method is simple and convenient for use and has extensive applicability.

Abstract: A radio frequency (RF) device includes an RF transceiver, an RF antenna, and a magnetic signal detector. The RF is selected to be in the very high frequency (VHF), ultrahigh frequency (UHF), or super high frequency (SHF) bands such that the shielding effect is reduced and the RF device can be configured as a SIM card disposed inside a cellular phone with an increased RF communication range. The magnetic signal detector is used to sense a magnetic field signal from an RF reader, which includes an RF transceiver, an RF antenna, and a magnetic signal transmitter. The longer communication range afforded by the VHF, UHF, or SHF bands is reduced by the sensing of the magnetic field, thereby providing a communication range control, while the RF device and the RF reader exchange information through the RF channel with improved security as a result of the range control.