Nippon Telegraph and Telephone Corporation

Toyota Jidosha Kabushiki Kaisha

Ai-ichiro Sasaki

Osamu Kagami

Fumiharu Morisawa

Hiroki Morimura

Akihiko Hirata

Junichi Kodate

Souichi Oka

Tsutomu Mizota

Hiroki Okada

Mitsuru Shinagawa

Tadashi Minotani

Jumpei Fuke

Nobutaro Shibata

Hiroko Okuyama

A dual loop antenna is provided which can clearly set a boundary of a communication area and create a well-balanced communication area. A dual loop antenna includes a first loop antenna and a second loop antenna. The first loop antenna and the second loop antenna are formed on an x-y plane. The center of the first loop antenna and the center of the second loop antenna are located at positions on an x-axis at the same distance from the point of origin being the center of the dual loop antenna. A phase difference between currents flowing on the first loop antenna and the second loop antenna, respectively, is a value in a range from 130 degrees to 230 degrees.

Dual loop antenna

Provided is a loop antenna array that can easily create a magnetic field distribution which enables the boundary of a communication area to be clearly set.loop antennae are provided adjacently to one another, where n is a natural number. The directions of currents in adjacent ones of the loop antennae are opposite to each other. For example, in a loop antenna array, two loop antennae are disposed adjacently to each other on an insulator substrate. First feed points energize one loop antenna and second feed points energize the other loop antenna.

Loop antenna array and loop antenna array group

Even when at least one of a capacitor (C) connected to a main loop and a capacitor (C) connected to an amplification loop cannot be set to an optimal value, a current value of a current (I) flowing on the amplification loop can be made sufficiently large by setting the capacitors (C, C) based on any of an optimal Ccurved line, an optimal Ccurved line, and an optimal Cstraight line that pass through an optimal point (C, C) of the capacitors (C, C) and extend along a ridge of contour lines each joining the points where the magnitude of the current (I) is equal on a diagram showing a relation of values of the capacitors (C, C) with the magnitude of the current (I).

Loop antenna and design method for loop antenna

A loop antenna array capable of forming a clear boundary of a communication area is provided. The loop antenna array includes three loop antennas, in which a direction of a current flowing through the loop antenna arranged in the middle and a direction of a current flowing through each of the loop antennas arranged on both sides of the loop antenna arranged in the middle are opposite from each other, and the sum of magnetic moments of the three loop antennas is zero.

Loop antenna array

Provided is a loop antenna which can contribute to an increase of an area of a radio system using a magnetic field. The loop antenna includes a main loopwhich is an open loop connected to a signal sourceor a reception circuit; and an amplification loopwhich is a closed loop having the same shape as the main loop. The main loopand the amplification loopare arranged on a same surface of a flat substrate formed of an insulator. A first capacitance is connected to the main loop, and a second capacitance is connected to the amplification loop.

Loop antenna

In an antenna circuit including an antennaand an antennathat is connected in series with the antennaand includes inductance, a variable capacitor Cand a variable resistor Rconnected in parallel with the antennaare provided. This enables controlling of an actual amplitude ratio r and a phase difference &#x3b8; between currents Iand Iflowing through the two antennasandinto desired values. Flows of the currents Iand Iwith the phase difference &#x3b8; through the antennasandenable forming of a favorable communication area. In addition, setting of the actual amplitude ratio r between the currents Iand Iflowing through the antennasandto a value other than 1 enables forming of an asymmetric communication area.

Antenna circuit

A main loop is an open loop that is wound on a bar-shaped rod formed of a magnetic body or an insulation body and that has terminals T and T that couple a signal source or a receiving circuit to the main loop. The number of turns is 1 or more. An amplifying loop is wound on a part of the rod that is different from the part on which the main loop is wound. The main loop and the amplifying loop are thus spaced from each other. The amplifying loop is a closed loop including no terminals. The number of turns is 1 or more. The number of turns may be the same as or different from the number of turns of the main loop.

A loop antenna array that can form a linear and clear communication area boundary is provided. The loop antenna array includes two loop antennas. Currents flow through the loop antennas in opposite directions from each other. In other words, viewing in a direction passing through each of the loop antennas, at a timing when a positive voltage is applied to a signal terminal of an alternating-current source, a clockwise current flows through one loop antenna while a counterclockwise current flows through the other loop antenna. Conversely, at a timing when a negative voltage is applied to the signal terminal of the alternating-current source, a counterclockwise current flows through one loop antenna while a clockwise current flows through the other loop antenna.

Provided is an antenna control technique for forming the boundary of a communication area at a desired location. An antenna parameter control apparatuscalculates an antenna parameter in a case of feeding electric currents with an equal intensity in mutually reverse directions to two antennasA,B which generate a magnetic field. The antenna parameter control apparatusincludes an input parameter acquisition unitthat acquires input parameters for calculating the antenna parameter; and a parameter calculation unitthat calculates an inter-center distance d between the antennasA,B as the antenna parameter based on the input parameters.

Antenna control apparatus, antenna control program, and antenna control system

A transceiver for inducing electric fields according to data to be transmitted in an electric field propagating medium, and carrying out at least data transmission by using induced electric fields, is formed by a transmission unit configured to modulate the data to be transmitted by generating alternating current signals having a prescribed frequency, and transmit modulated signals obtained by modulating the data to be transmitted, and a resonance causing unit configured to cause a series resonance with a parasitic capacitance appearing between a ground for the transmission unit and an Earth ground and a parasitic capacitance appearing between the electric field propagating medium and the Earth Ground.

Growing community of inventors

Atsugi, Japan

Ai-ichiro Sasaki