Matsushita Electric Industrial Co., Ltd.

Hiroaki Haruyama

Futoshi Deguchi

Masahiko Tanaka

Hiroshi Yoshinaga

Takashi Yamaguchi

Akihiko Hirata

Yoshiyuki Ogata

The object of the invention is to provide a noncontact IC card reader/writer integrated with an antenna that does not require the limitation of an installation location and the adjustment of a resonance frequency of the antenna, is convenient in installation, is provided with a stable characteristic, is small-sized and low-priced. To achieve the object, the invention is provided with a loop antenna that supplies electric power and send data to a noncontact IC card by electromagnetic induction and acquires receive data from the noncontact IC card by load fluctuation, a magnetic body arranged closely at the back of the loop antenna, a first metallic plate arranged on the back side of the magnetic body and a second metallic plate arranged on the back side of the first metallic plate and larger than the first metallic plate in size.

Noncontact recording medium reader/writer

A gate antenna device has a plurality of loop antennas which supplies power and transmission data to an IC-integrated medium through electromagnetic induction and acquires reception data in the form of a fluctuation of a load from the IC-integrated medium. The plurality of loop antennas include a power-fed loop antenna to which a signal current is supplied and a non-power-fed loop antenna to which no signal current is supplied. The gate antenna device expands the distance and range of communication with an IC-integrated medium and improves the accuracy of communication while suppressing power consumption and leakage electric fields.

Gate antenna device

The object of the invention is to provide a small-sized noncontact IC card reader/writer that can enhance the efficiency of an amplifier at a low cost. To achieve the object, in the invention, a loop antenna that supplies electric power and a send signal to a noncontact IC card by electromagnetic induction and acquires a receive signal from the noncontact IC card by load fluctuation, a first resonance circuit for resonating the loop antenna with a desired first frequency, a radio transmitter that supplies electric power and send data to the loop antenna via the first resonance circuit and further, a radio receiver that acquires the receive signal from the loop antenna via a second resonance circuit connected to the loop antenna via a coupling capacitor and resonated with a desired second frequency are provided, the radio transmitter and the radio receiver are respectively connected to CPU, and a low-pass filter for removing a high frequency, a class E amplifier and a modulator are connected to the radio transmitter in series.

Noncontact IC card reader/writer

To provide a loop antenna capable of attenuating the distant electric field with the attenuation of the magnetic flux in the vicinity of an electromagnetic wave restrained, and a contactless IC card read/write apparatus. A loop antennahas an electromagnetic wave shieldover at least one side of the loop antenna, the electromagnetic wave shieldcomprising a plurality of electric conductorsa ground contactfor grounding the plurality of electric conductors and a lead wirefor connecting the plurality of electric conductorsto the ground contactThe plurality of electric conductorsare electrically connected via the lead wireto the ground contactand the plurality of electric conductorsare arranged so that the paths of the respective electric conductorsfrom any of their given points to the ground contactvia the lead wireare determined uniformly.

Loop antenna and contactless IC card read/write apparatus

A signal generator for generating a high frequency without using a VCO and a loop filter is disclosed. A digital signal tapped off from a digital synthesizer generating a digital signal corresponding to a desired frequency is converted into an analog signal by a D/A converter. This signal is deprived of its unwanted wave signal components by a bandpass filter, and the analog signal thus obtained is used as an RF signal. A frequency-multiplied signal of an output signal of a reference signal generator generating the reference signal is supplied to a mixer as a local oscillation signal. The mixer mixes the RF signal supplied thereto with the local oscillation signal to frequency-convert the signals into a high-frequency signal. The high-frequency signal is deprived of its out-of-band noises by a filter to provide a local oscillation signal for use in a communication apparatus.

Signal generator

A high-frequency radio signal receiving apparatus for digital communication includes a receiving antenna for receiving a high-frequency radio wave, a frequency converter for converting a signal supplied from the receiving antenna through a wide-band bandpass filter into a signal of an intermediate frequency band, an impulsive noise detecting unit for detecting impulsive noise on the basis of a signal outputted from the frequency converter. The apparatus further includes an impulsive noise correcting unit for correcting the signal outputted from the frequency converter in dependence on a signal outputted from the impulsive noise detecting unit, and a demodulating unit for demodulating a signal outputted from the impulsive noise correcting unit and supplied by way of a narrow-band bandpass filter.

Growing community of inventors

Fukuoka, Japan

Hiroaki Haruyama