Abstract: An antenna device includes a feeding coil antenna and a booster coil antenna electromagnetically coupled to the feeding coil antenna. The feeding coil antenna includes a plurality of coil portions including at least one magnetic body and each including a coil conductor wound around the at least one magnetic body. The plurality of coil portions are connected to one another in an in-phase mode, and are arranged near one another such that winding axes of the coil conductors are oriented approximately in the same direction and at least portions of respective openings of the coil conductors face one another.

Abstract: An antenna apparatus and a radio communication apparatus are capable of separately controlling a resonance frequency in a basic mode and a resonance frequency in a higher mode and have a wide bandwidth in which the resonance frequency in the basic mode is variable. The antenna apparatus includes a feeding electrode 2, a loop-shaped radiation electrode 3, a capacitance portion 4, and inductors 5 and 6. The capacitance portion 4 is formed by a gap between an open end 3a of the loop-shaped radiation electrode 3 and the feeding electrode 2. The inductor 5 is disposed at a position where a large current is obtained in the basic mode and a small current is obtained in the higher mode. The inductor 6 is disposed at a position where a large current is obtained in the higher mode and a small current is obtained in the basic mode.

Abstract: An antenna device includes a base including a planar conductor disposed thereon, and a coil antenna. The coil antenna includes a coil conductor wound around a magnetic core. The coil antenna is arranged such that a coil opening of the coil conductor is closed to an edge of the planar conductor. A current passing through the coil conductor induces a current in the planar conductor. Thus, a first magnetic flux occurs in the coil antenna, and a second magnetic flux occurs in the planar conductor. Therefore, a third magnetic flux occurs in an area of the planar conductor. Accordingly, the antenna device achieves a small footprint, a small-sized communication terminal apparatus and a desired communication distance.

Abstract: An RFID module includes an RFIC element, a filter circuit, a matching circuit, and a radiating element. The filter circuit and the matching circuit define an RFID device. The filter circuit includes a first inductance element, a second inductance element, and a capacitor. The first inductance element and the second inductance element are of equal inductance, and are strongly magnetically coupled to each other so as to strengthen magnetic fluxes to each other. With this configuration, an RFID module and an RFID device that include a filter circuit to remove harmonic components of the RFIC element but are not large as a whole are constructed.

Abstract: A compact and low-cost antenna device in which no interference occurs even when many antenna units corresponding to various systems are mounted close together in a small area, and a wireless communication apparatus including the antenna device. An antenna device includes plural antenna units mounted on a single dielectric base. A first antenna unit having a lowest fundamental frequency is disposed at a left end of a non-ground region, a second antenna unit having a highest fundamental frequency of the plurality of the antenna units is disposed at a right end of the non-ground region, and a third antenna unit having a fundamental frequency between those of the first antenna unit and the second antenna unit is disposed between the first and second antenna units. A current-density control coil is connected between a first radiation electrode and a power feeder of the first antenna unit, while a reactance circuit is disposed in the middle of the first radiation electrode.

Abstract: An antenna device capable of not only achieving multiple resonances and wideband characteristics but also achieving improvement of antenna efficiency and accurate matching at all resonant frequencies, and a wireless communication apparatus. In one example, an antenna device 1 includes a radiation electrode 2 to which power is capacitively fed through a capacitor portion C1, and additional radiation electrodes 3-1 to 3-3 branched from the radiation electrode 2. A distal end portion 2a of the radiation electrode 2 is grounded to a ground region 402, and is a portion at which a minimum voltage is obtained when power is fed. A capacitor portion C2 that is a portion at which a maximum voltage is obtained when power is fed is disposed in a proximal end portion 2b of the radiation electrode 2, and a variable capacitance element 4 which is grounded is connected in series with the capacitor portion C2.

Abstract: A ground electrode is formed on the lower surface of a ferroelectric substrate, a control electrode including capacitor electrodes and an inductor electrode is formed on the upper surface of the ferroelectric substrate, and an upper-surface radiating electrode and an end-surface radiating electrode are formed on a paraelectric substrate. The shapes and dimensions of the ferroelectric substrate, paraelectric substrate, and radiating electrodes are determined such that when the ferroelectric substrate and the paraelectric substrate are stacked in layers, a circuit including the radiating electrodes resonates at frequencies outside a frequency band exhibiting frequency dispersion of a dielectric constant.

Abstract: A compact and low-cost antenna device in which no interference occurs even when many antenna units corresponding to various systems are mounted close together in a small area, and a wireless communication apparatus including the antenna device. An antenna device includes plural antenna units mounted on a single dielectric base. A first antenna unit having a lowest fundamental frequency is disposed at a left end of a non-ground region, a second antenna unit having a highest fundamental frequency of the plurality of the antenna units is disposed at a right end of the non-ground region, and a third antenna unit having a fundamental frequency between those of the first antenna unit and the second antenna unit is disposed between the first and second antenna units. A current-density control coil is connected between a first radiation electrode and a power feeder of the first antenna unit, while a reactance circuit is disposed in the middle of the first radiation electrode.

Abstract: An antenna device capable of not only achieving multiple resonances and wideband characteristics but also achieving improvement of antenna efficiency and accurate matching at all resonant frequencies, and a wireless communication apparatus. In one example, an antenna device 1 includes a radiation electrode 2 to which power is capacitively fed through a capacitor portion C1, and additional radiation electrodes 3-1 to 3-3 branched from the radiation electrode 2. A distal end portion 2a of the radiation electrode 2 is grounded to a ground region 402, and is a portion at which a minimum voltage is obtained when power is fed. A capacitor portion C2 that is a portion at which a maximum voltage is obtained when power is fed is disposed in a proximal end portion 2b of the radiation electrode 2, and a variable capacitance element 4 which is grounded is connected in series with the capacitor portion C2.

Abstract: A ground electrode is formed on the lower surface of a ferroelectric substrate, a control electrode including capacitor electrodes and an inductor electrode is formed on the upper surface of the ferroelectric substrate, and an upper-surface radiating electrode and an end-surface radiating electrode are formed on a paraelectric substrate. The shapes and dimensions of the ferroelectric substrate, paraelectric substrate, and radiating electrodes are determined such that when the ferroelectric substrate and the paraelectric substrate are stacked in layers, a circuit including the radiating electrodes resonates at frequencies outside a frequency band exhibiting frequency dispersion of a dielectric constant.

Abstract: A radiation electrode is formed on a substrate of a surface mount antenna. One end of the radiation electrode forms a ground connection portion connected to ground, and the other end of the radiation electrode forms an open end. A ground connection electrode for connecting the open end of the radiation electrode to ground via a capacitance is provided on the substrate. No feeding electrode for feeding power to the radiation electrode is provided on the substrate. This surface mount antenna is mounted on a non-ground region (a region on which a ground electrode is not formed) of a board so as to constitute an antenna structure. On the board of the antenna structure, a feeding electrode for capacitively feeding power to the radiation electrode is provided at a position between the ground connection portion and the open end.

Abstract: Power non-supplied side radiation electrode 3 and power supplied side radiation electrode 4 are formed on the surface of a dielectric substrate 2 with a space therebetween. A permittivity adjusting material portion 8 is provided in the space S which is situated between the power non-supplied side radiation electrode 3 and the power supplied side radiation electrode 4, and in which a capacity occurs. The permittivity adjusting material portion 8 has a lower permittivity than that of the dielectric substrate 2, which causes the permittivity between the power non-supplied side radiation electrode 3 and the power supplied side radiation electrode 4 to be lower than that of dielectric substrate 2, and weaken the capacitive coupling between the power non-supplied side radiation electrode 3 and the power supplied side radiation electrode 4.

Abstract: A surface-mounted type antenna which facilitates the realization of the widening of the frequency band, and a communication device including it. In this antenna, the strong electric-field regions of a power supplied first radiation electrode and a power non-supplied second radiation electrode are disposed adjacent to each other with a spacing therebetween, and simultaneously the high current regions of these radiation electrodes are disposed adjacent to each other with a spacing therebetween. By variably adjusting the quantity of the electric-field coupling between the strong electric-field regions of the first radiation electrode and the second radiation electrode, and by variably adjusting the quantity of the magnetic-field coupling between the high current regions of these radiation electrodes, both the quantities of the electric-field coupling and the magnetic-field coupling are set to conditions suited for the dual resonance. A superior dual resonance is thereby achieved.

Abstract: In a feeding radiation electrode of a surface mount antenna, a series inductance component such as a meander pattern is formed locally in a maximum resonance current part in a high-order mode (second-order mode) so as to locally form a series inductance component therein thereby making the maximum resonance current part have a greater electrical length per unit physical length than the other parts. This makes it possible to control the difference between the resonance frequency in a fundamental mode and the resonance frequency in the high-order mode over a large range. Furthermore, it is possible to vary the resonance frequency in the second-order mode independently of the resonance frequency in the fundamental mode by varying the number of lines or the line-to-line distance of the meander pattern thereby varying the value of the series inductance component.

Abstract: A multi-band surface-mounted antenna is formed by disposing a feeding element and a non-feeding element with a distance therebetween on a dielectric base member. The feeding element is formed by extending a feeding radiation electrode from a feeding terminal. The non-feeding element is a branched element formed by branching and extending a first radiation electrode and a second radiation electrode of the non-feeding side from a ground terminal side. The single surface-mounted antenna includes the three radiation electrodes. Thus, the antenna can be easily adapted to multi-bands. In addition, the resonance waves of the three radiation electrodes can be controlled mutually independently. As a result, only a frequency band selected from a plurality of required frequency bands is brought into a multi-resonance state so that the frequency band can be broadened.

Abstract: A multi-band surface-mounted antenna is formed by disposing a feeding element and a non-feeding element with a distance therebetween on a dielectric base member. The feeding element is formed by extending a feeding radiation electrode from a feeding terminal. The non-feeding element is a branched element formed by branching and extending a first radiation electrode and a second radiation electrode of the non-feeding side from a ground terminal side. The single surface-mounted antenna includes the three radiation electrodes. Thus, the antenna can be easily adapted to multi-bands. In addition, the resonance waves of the three radiation electrodes can be controlled mutually independently. As a result, only a frequency band selected from a plurality of required frequency bands is brought into a multi-resonance state so that the frequency band can be broadened.

Abstract: In a feeding radiation electrode of a surface mount antenna, a series inductance component such as a meander pattern is formed locally in a maximum resonance current part in a high-order mode (second-order mode) so as to locally form a series inductance component therein thereby making the maximum resonance current part have a greater electrical length per unit physical length than the other parts. This makes it possible to control the difference between the resonance frequency in a fundamental mode and the resonance frequency in the high-order mode over a large range. Furthermore, it is possible to vary the resonance frequency in the second-order mode independently of the resonance frequency in the fundamental mode by varying the number of lines or the line-to-line distance of the meander pattern thereby varying the value of the series inductance component.

Abstract: A first radiating electrode 5 and radiating electrode 6 are formed on an upper face 2c of a dielectric base 2 of a surface-mounted antenna 1, and a rectifying circuit 7 is formed on a side face 2b where radiating electrodes 5 and 6 are not formed. This facilitates configuration of a desired rectifying circuit 7 appropriate for the surface-mounted antenna 1, and rectification of the surface-mounted antenna 1 is facilitated. Also, since the rectifying circuit 7 is formed on the side face 2b of the dielectric base 2, effects of the rectifying circuit 7 on the first radiating electrode 5 and second radiating electrode 6 on the upper face 2c can be reduced. Accordingly, high gain and increased bandwidth of the surface-mounted antenna can be obtained.

Abstract: A surface-mount antenna includes a dielectric substrate having a rectangular parallelepiped shape and a radiation electrode having a meandering pattern disposed on the surface of the dielectric substrate. The radiation electrode includes at least two meandering electrode units formed with different meander pitches, the at least two meandering electrode units being connected in series, and the radiation electrode being formed over at least two faces among a front face, a major surface, and a end surface of the dielectric substrate. With the above-described construction, the radiation electrode is allowed to transmit and receive electromagnetic waves in at least two different frequency bands.

Abstract: A surface-mounted type antenna which facilitates the realization of the widening of the frequency band, and a communication device including it. In this antenna, the strong electric-field regions of a power supplied first radiation electrode and a power non-supplied second radiation electrode are disposed adjacent to each other with a spacing therebetween, and simultaneously the high current regions of these radiation electrodes are disposed adjacent to each other with a spacing therebetween. By variably adjusting the quantity of the electric-field coupling between the strong electric-field regions of the first radiation electrode and the second radiation electrode, and by variably adjusting the quantity of the magnetic-field coupling between the high current regions of these radiation electrodes, both the quantities of the electric-field coupling and the magnetic-field coupling are set to conditions suited for the dual resonance. A superior dual resonance is thereby achieved.