Abstract: There is provided an RF tag reader and writer including: a transmission antenna configured to transmit a desired signal; a receiving antenna configured to receive radio waves transmitted from an RF tag which is a communication target; a return-loss determination unit configured to determine the receiving intensity of the receiving antenna with respect to reflected waves of radio waves radiated from the transmission antenna; and a reading control unit configured to start a reading operation of the RF tag by being triggered by a return loss value determined by the return-loss determination unit.

Abstract: According to the product administration system of the present embodiment, the radio tag having the acceleration sensor and the inquiry unit for communication with the radio tag are provided, the inquiry unit sets a direction of acceleration and a threshold value of the acceleration in the direction in the radio tag by communication, and the set radio tag responds to an inquiry from the inquiry unit when it exceeds the threshold value.

Abstract: A commodity settlement system processes settlement for a commodity carrying an RF tag, communicating with the RF tag for data associated with the commodity stored in an RF tag. The RF tag comprises a capacitor, a memory, and an antenna, the RF tag being capable of receiving a radiowave from an external device, charges the capacitor with a direct current converted by the rectifier circuit from a current induced in the antenna by receiving a radiowave from an external device, and stores temporary settlement information in the memory. The commodity settlement system includes a first RF tag reader/writer connected to an antenna disposed on a commodity shelf. The first RF tag reader/writer sets the temporary settlement information in the memory to an “unsettled” state through the antenna disposed on the commodity shelf at intervals of a predetermined time.

Abstract: A diversity apparatus includes a transceiver, a phase shifter which switches phases of a carrier wave transmitted from the transceiver, and a leakage transmission path which transmits the carrier wave output from the phase shifter. The transceiver switches a phase of the phase shifter depending on a receiving level.

Abstract: A quadrature demodulator includes a reception section which receives a signal transmitted by an RFID tag and containing a specific pattern and data following the specific pattern and multiplies the reception signal by a local signal to generate an I-signal, while multiplying the reception signal by the local signal shifted in phase by 90 degrees to generate a Q-signal, a first demodulating circuit which squares the I- and Q-signals and adding the resulting I- and Q-signals together to generate data on the basis of the addition result, a second demodulating circuit which detects the specific pattern in the I- and Q-signals to decode the data following one of the detected specific patterns, and a control section which selects one of the first and second demodulating circuits in accordance with a gain determined by the result of the addition between the values of the squared I- and Q-signals.

Abstract: A reader antenna is connected to an interrogator. Conductors are arranged at two places at the opposed marginal edge portions of a radiation plane of the reader antenna along a radiation direction of an electromagnetic wave from the reader antenna. The conductors raises the electric power density above the reader antenna. A storage case is set above the reader antenna and has many items arranged at narrow intervals with radio tags attached thereto. The storage container has the radio tags arranged substantially parallel to the polarization direction of the reader antenna. By doing so, adequate drive power is applied to the radio tag by an electromagnetic wave from the reader antenna.

Abstract: In a receiving section, a first mixer and a second mixer generate an I signal and a Q signal from a modulated reception signal, a local signal, and a local signal obtained by shifting a phase by 90 degrees. These I signal and Q signal are supplied to a digital signal processing section via a low path filter, a capacitor, a variable gain amplifier, and an ADC. In addition, the generated I signal and Q signal are directly supplied to the digital signal processing section. The digital signal processing section detects a sign of the I signal and a sign of the Q signal, the signals being directly input. In addition, the detected sign of the I signal is multiplied with the I signal input from the ADC, and then, the detected sign of the Q signal is multiplied with the Q signal input from the ADC, whereby the signs are commonly established in a positive state. Then, the I signal and the Q signal are added, and decoded into two-values.

Abstract: A quadrature demodulator generates an I-signal from a modulated reception signal and a local signal, generates a Q-signal from the local signal and the local signal having a phase shifted through 90 degrees. Capacitors remove DC components from the I- and Q-signals. Low-pass filters remove frequency components higher than the frequencies of the I- and Q-signals. An I-signal squaring section squares the I-signal having passed through the low-pass filters. A Q-signal squaring section squares the Q-signal having passed through the low-pass filters. An adding section adds the squared I-signal and the squared Q-signal together. A comparator then compares the level of an S1 signal resulting from the addition with a threshold to obtain an S2 signal. A data generating section of a digital signal processing section executes a process of inverting the signal level of the S2 signal at every rising edge of the S2 signal to demodulate reception data.

Abstract: A quadrature demodulator includes a reception section which receives a signal transmitted by an RFID tag and containing a specific pattern and data following the specific pattern and multiplies the reception signal by a local signal to generate an I-signal, while multiplying the reception signal by the local signal shifted in phase by 90 degrees to generate a Q-signal, a first demodulating circuit which squares the I- and Q-signals and adding the resulting I- and Q-signals together to generate data on the basis of the addition result, a second demodulating circuit which detects the specific pattern in the I- and Q-signals to decode the data following one of the detected specific patterns, and a control section which selects one of the first and second demodulating circuits in accordance with a gain determined by the result of the addition between the values of the squared I- and Q-signals.

Abstract: In a receiving section, a first mixer and a second mixer generate an I signal and a Q signal from a modulated reception signal, a local signal, and a local signal obtained by shifting a phase by 90 degrees. These I signal and Q signal are supplied to a digital signal processing section via a low path filter, a capacitor, a variable gain amplifier, and an ADC. In addition, the generated I signal and Q signal are directly supplied to the digital signal processing section. The digital signal processing section detects a sign of the I signal and a sign of the Q signal, the signals being directly input. In addition, the detected sign of the I signal is multiplied with the I signal input from the ADC, and then, the detected sign of the Q signal is multiplied with the Q signal input from the ADC, whereby the signs are commonly established in a positive state. Then, the I signal and the Q signal are added, and decoded into two-values.

Abstract: An identification information reader includes an antenna commonly used for transmission of a radio wave to a radio frequency identification tag and reception of a radio wave that has been modulated with at least identification information and transmitted from a radio frequency identification tag, a transmitter which outputs a radio wave to be transmitted from the antenna, a receiver which demodulates a radio wave received by the antenna to acquire at least the identification information, a directional coupler which is connected between the transmitter and the receiver, guides the radio wave output from the transmitter to the antenna and guides the radio wave received by the antenna to the receiver, and an attenuator which is connected between the antenna and the directional coupler and attenuates the radio wave guided to the receiver to reduce saturation of the receiver due to an increase in voltage standing wave ratio of the antenna.

Abstract: An RF tag reading apparatus reads information from RF tags affixed to postal envelopes by a single operation. An article container contains a large number of postal envelopes provided with RF tags. A reader antenna, which is connected to an interrogator via a coaxial cable, is disposed under the article container. Maximum gain directions of the RF tags of the respective postal envelopes are uniformly directed to the reader antenna. The respective postal envelopes contained in the article container are arranged face to face with each other in a direction orthogonal to the maximum directions of the RF tags. Since a maximum gain direction of the reader antenna is oriented toward a base end surface of the article container, the maximum gain directions of the RF tags are opposed to the maximum gain direction of the reader antenna.

Abstract: A wireless base station uses a leaky transmission line as an antenna, and a wireless base station uses a leaky transmission line as an antenna. The leaky transmission line and the leaky transmission line are laid parallel to each other. An interval between the leakage transmission paths is set to a distance at which it is impossible for the wireless base stations to sense each other's carrier while using a same wireless channel, and to be not more than twice as long as a maximum distance between leaky transmission lines, and wireless communication terminals at which it is possible for wireless base stations to respectively establish wireless links to wireless communication terminals.

Abstract: A diversity apparatus includes a transceiver, a phase shifter which switches phases of a carrier wave transmitted from the transceiver, and a leakage transmission path which transmits the carrier wave output from the phase shifter. The transceiver switches a phase of the phase shifter depending on a receiving level.

Abstract: There is provided an antenna device used in a radio-communication between a radio communication apparatus and a data carrier within a short communication range. The antenna device comprises first and second leakage transmission lines, and a switch for selectively connecting the first and second transmission lines to the radio communication apparatus when carrying out the radio communication. The first transmission line has an opened end terminal. The second transmission line has a short-circuited end terminal. The first and second transmission lines are arranged in parallel and end terminals thereof are aligned.

Abstract: A direct conversion radio apparatus comprises a local oscillator which generates a high-frequency signal of almost the same frequency as that of a signal to be received, a modulator which modulates the high-frequency signal generated from the local oscillator in carrier sensing, mixers which frequency-convert a received signal into a baseband frequency by using the high-frequency signal modulated by the modulator in carrier sensing, low-pass filters which limit bands of baseband signals extracted by frequency-converting by the mixers, and a baseband circuit which controls the frequency of the high-frequency signal generated from the local oscillator and also performs carrier sensing by amplitude of the baseband signals output from the low-pass filters.

Abstract: There is disclosed an RF tag holding structure that can maintain sufficient performance of data-reading from an RF tag when the structure mounting a commercially available RF tag is attached to an article, or even if a number of planar articles each carrying an RF tag are closely arranged sideways so as to face each other on its planar surface. A narrow rectangular thru-opening 3 is formed on a side of one longer edge line of a holding member 1, wherein the rectangular thru-opening 3 is provided in such a size that an IC chip 21 and antenna 22 in the RF tag 2 can be disposed in the air space of the thru-opening. A supporting part for holding the RF tag within the thru-opening is formed on the internal circumference of the thru-opening of the holding member 1 such that the RF tag is supported so as not to overlap an antenna on a substrate in the thru-opening direction.

Abstract: An RF tag reading apparatus reads information from RF tags affixed to postal envelopes by a single operation. An article container contains a large number of postal envelopes provided with RF tags. A reader antenna, which is connected to an interrogator via a coaxial cable, is disposed under the article container. Maximum gain directions of the RF tags of the respective postal envelopes are uniformly directed to the reader antenna. The respective postal envelopes contained in the article container are arranged face to face with each other in a direction orthogonal to the maximum directions of the RF tags. Since a maximum gain direction of the reader antenna is oriented toward a base end surface of the article container, the maximum gain directions of the RF tags are opposed to the maximum gain direction of the reader antenna.

Abstract: An RF tag reading apparatus reads information from RF tags affixed to postal envelopes by a single operation. An article container contains a large number of postal envelopes provided with RF tags. A reader antenna, which is connected to an interrogator via a coaxial cable, is disposed under the article container. Maximum gain directions of the RF tags of the respective postal envelopes are uniformly directed to the reader antenna. The respective postal envelopes contained in the article container are arranged face to face with each other in a direction orthogonal to the maximum directions of the RF tags. Since a maximum gain direction of the reader antenna is oriented toward a base end surface of the article container, the maximum gain directions of the RF tags are opposed to the maximum gain direction of the reader antenna.