A method of detecting products includes a magnetic field generating device configured to generate a magnetic field, and a split ring resonator assembly configured to be magnetically coupled to the magnetic field generating device and configured to focus the magnetic field produced by the magnetic field generating device.

An antenna device according to an embodiment includes an antenna including a power feeding point, a matching circuit having a variable impedance, a loop type probe being installed near the power feeding point and receiving a radio wave radiated from the antenna, a power detector detecting electric power of the radio wave received by the loop type probe, and a control circuit controlling an impedance of the matching circuit on the basis of power information output from the power detector.

An antenna device includes a substrate; a first linear conductive element that is disposed on the substrate so as to have a loop shape line-symmetric with respect to a first straight line and a second straight line that is orthogonal to the first straight line, the first linear conductive element having a first electrical length between intersections of the first linear conductive element and the second straight line that is an integer multiple of a wavelength at a resonance frequency; and a second linear conductive element that is disposed on the substrate and is substantially parallel to the second straight line, the second linear conductive element having a second electrical length that is a half wavelength of the wavelength at the resonance frequency.

A pulse generator that includes a communications module is disclosed herein. The communication module includes a transceiver and an antenna circuit. The antenna circuit includes a first pathway having a capacitor and a second, parallel pathway including a capacitor, and a resistor, and a radiating element arranged in series. The antenna circuit is tuned to have a resonant frequency corresponding to a desired transmission frequency and a bandwidth corresponding to shifts in the resonant frequency arising from the implantation of the antenna.

An arrangement for modifying a printed circuit antenna of the type used in mobile communication devices includes introducing one or more discontinuities into a printed circuit pattern of the antenna so that it is not activated at undesired frequencies. Examples of discontinuities include localized narrowing the printed circuit strip, localized widening of the printed circuit strip and localized changing of the shape of the printed circuit strip.

A communication device including a device-side antenna 30 for wireless communication with an IC card 10 including a card-side antenna 11 wound in a rectangular form. The antenna 30 is formed in one or multiple loops. During the wireless communication with the IC card 10 having an inner perimeter with a long dimension of 69 mm and a short dimension of 38 mm at a distance of 25 mm, an inner perimeter of the antenna 30 is formed at a position at which intensity H of a magnetic field produced by the card-side antenna 11 in a direction perpendicular to a surface on which the antenna 30 is disposed is in a range expressed by inequation (1):

0.037I/4Π<H<0.063I/4Π  (1)

where I is a current of the card-side antenna [A] and Π is pi.

An RFIC device including a resin block having a first surface, a second surface that faces the first surface, and a through-hole that extends through the first surface and the second surface. Moreover, the RFIC device includes an RFIC element that is embedded in the resin block and a coil antenna disposed in the resin block that is connected with the RFIC element and that has a central axis that extends from the first surface to the second surface. In addition, the through-hole extends inside the coil antenna.

One example discloses a near-field device, including: a near-field magnetic antenna, including a coil, configured to receive or transmit near-field magnetic signals; a near-field electric antenna configured to receive or transmit near-field electric signals; and a set of electrical components, electrically coupled to the near-field magnetic antenna and the near-field electric antenna; wherein at least one of: the coil of the near-field magnetic antenna, or a conductive surface of the near-field electric antenna, forms a boundary around the set of electrical components.

Circuits and methods concerning radio frequency (RF) communication are disclosed. In some example embodiments, an apparatus includes a first antenna providing a signal path, having at least one loop, between a first pair of nodes. The apparatus also includes a second antenna providing a signal path, having one or more loops, between a second pair of nodes. The second antenna is placed sufficiently close to the first antenna to cause the second antenna to resonate in response to an RF signal being applied to the first pair of nodes by a communication circuit.

A system includes an antenna, an impedance measurement circuit, an impedance tuning circuit, and a controller. The impedance measurement circuit can include a test current source that conveys a test current through the antenna, and a voltage sensor that measure a voltage across the antenna while the test current is conveyed through the antenna. The impedance tuning circuit can be coupled to the antenna leads and can include one or more reactive elements that can be selectively coupled to the antenna, or otherwise adjusted, to effect adjustment of the impedance connected to the antenna. The controller can: (i) use the impedance measurement circuit to obtain a measurement indicative of an impedance of the antenna; (ii) determine an adjustment to the impedance tuning circuit based on the obtained measurement; and (iii) cause the impedance tuning circuit to make the determined adjustment.