Abstract: A low-frequency radiating element and a high-frequency radiating element are configured so as to respectively operate in a relatively low frequency band and a relatively high frequency band that are non-contiguous with each other. A matching circuit is inserted between a transmission/reception circuit and a branching point. A high-frequency variable reactance circuit is inserted between the branching point and the high-frequency radiating element. A low-frequency variable reactance circuit is inserted between the branching point and the low-frequency radiating element. The high-frequency variable reactance circuit and the low-frequency variable reactance circuit are configured such that their reactances can be adjusted independently of each other.

Abstract: An antenna device can detect the surrounding environment and appropriately corrected and maintain stable antenna characteristics. The antenna device includes at least first and second antenna element electrodes, an antenna matching circuit provided along a wireless communication signal path for the first antenna element electrode, a capacitance detection circuit connected to the second antenna element electrode and operable to detect stray capacitance of the antenna element electrode using a sensing signal. A matching control circuit controls the antenna matching circuit in accordance with an output signal of the capacitance detection circuit.

Abstract: This disclosure provides an antenna apparatus in which stable antenna characteristics are maintained by detecting surrounding conditions that affect the antenna characteristics and appropriately compensating the antenna characteristics. More specifically, when surrounding condition such as a human body (e.g., a palm or fingers) approaches and enters an electric field of a pseudo dipole formed by an antenna element electrode, a stray capacitance is sensed and stable antenna characteristics are maintained by appropriately controlling an antenna matching circuit to compensate for a change in the antenna characteristics due to the approach of the surrounding condition.

Abstract: A switching function and multiband compatibility and a function handling deviation of matching caused by the influence of the human body are configured in a single matching circuit. An antenna matching circuit is formed by a reactance changing section and a matching section. The matching section is formed by a parallel circuit of an inductor and a capacitor, and the LC parallel circuit is shunt-connected between a feed section and the ground. The reactance changing section changes the resonant frequency to be compatible with a plurality of bands, and performs fine adjustment of the resonant frequency changed by the influence of the human body. The parallel inductor causes the locus of input impedance of the antenna matching circuit to draw a small circle locus in the first quadrant of a Smith chart. The parallel capacitor is adjustable to move the small circle locus to the center on the Smith chart.

Abstract: In an antenna structure in which a base is mounted in a ground region on a circuit board, the base having formed thereon a driven radiating electrode and a parasitic radiating electrode, the parasitic radiating electrode causing multiple resonance at least in a harmonic resonant frequency band of the driven radiating electrode, capacitance loading means for loading a capacitance to a harmonic-mode zero voltage region of the driven radiating electrode is provided. The capacitance loading means is electrically connected to a ground electrode in the ground region on the circuit board via a grounding conduction path and switching means. By switching the switching means ON/OFF, capacitance loading by the capacitance loading means to the harmonic-mode zero voltage region of the driven radiating electrode is switched ON/OFF to switch a base resonant frequency in a base resonant frequency band of the driven radiating electrode.

Abstract: In an antenna structure 1 in which a feed radiation electrode provided on a dielectric base member performs an antenna operation in a fundamental mode and an antenna operation in a higher-order mode with a resonant frequency higher than that in the fundamental mode, one end of the feed radiation electrode defines a feed end connected to a circuit for radio communication, and the other end of the feed radiation electrode defines an open end. The position of a capacitance-loading portion ? is set in advance between the feed end and the open end of the feed radiation electrode. A capacitance-loading conductor is connected to one or both of the feed end and the capacitance-loading portion ? of the feed radiation electrode. The capacitance-loading conductor forms a capacitance for adjusting a resonant frequency in the fundamental mode between the feed end and the capacitance-loading portion ?.

Abstract: In an antenna structure in which a base is mounted in a ground region on a circuit board, the base having formed thereon a driven radiating electrode and a parasitic radiating electrode, the parasitic radiating electrode causing multiple resonance at least in a harmonic resonant frequency band of the driven radiating electrode, capacitance loading means for loading a capacitance to a harmonic-mode zero voltage region of the driven radiating electrode is provided. The capacitance loading means is electrically connected to a ground electrode in the ground region on the circuit board via a grounding conduction path and switching means. By switching the switching means ON/OFF, capacitance loading by the capacitance loading means to the harmonic-mode zero voltage region of the driven radiating electrode is switched ON/OFF to switch a base resonant frequency in a base resonant frequency band of the driven radiating electrode.

Abstract: In an antenna structure 1 in which a feed radiation electrode provided on a dielectric base member performs an antenna operation in a fundamental mode and an antenna operation in a higher-order mode with a resonant frequency higher than that in the fundamental mode, one end of the feed radiation electrode defines a feed end connected to a circuit for radio communication, and the other end of the feed radiation electrode defines an open end. The position of a capacitance-loading portion ? is set in advance between the feed end and the open end of the feed radiation electrode. A capacitance-loading conductor is connected to one or both of the feed end and the capacitance-loading portion ? of the feed radiation electrode. The capacitance-loading conductor forms a capacitance for adjusting a resonant frequency in the fundamental mode between the feed end and the capacitance-loading portion ?.

Abstract: In an antenna, a feeding radiation element and a first non-feeding radiation element that are loaded with dielectric substances are provided on a ground electrode, and a second non-feeding radiation element is disposed such that substantially the entire second non-feeding radiation element projects outside from a desired side of the ground electrode. More specifically, each of the three electrode elements is loaded with a dielectric substance, and a radiation electrode of the second non-feeding radiation element is electrically connected at a substantially central location of the desired side of the ground electrode via a connection wire.

Abstract: A feed radiation electrode including two branched radiation electrodes is provided on the surface of a substrate. Non-feed radiation electrodes are provided on both sides of the feed radiation electrode and near the branched radiation electrodes. The branched radiation electrode and the non-feed radiation electrode are double-resonated in the same frequency band. The branched radiation electrode and the non-feed radiation electrode are double-resonated in the same frequency band which is higher than that of the branched radiation electrode and the non-feed radiation electrode.

Abstract: In a multi-resonance antenna, at an open end of a radiation electrode of a feeding element and an open end of a radiation electrode of a parasitic element capacitance loading electrodes and ground electrodes are arranged opposite to each other. In the opposing portions, electric-field deflectors are provided, thus reducing the electric-field coupling between the feeding element and the parasitic element.

Abstract: AtIn a multi-resonance antenna, at an open end (18A) of a radiation electrode (18) of a feeding element (16) and an open end (19A) of a radiation electrode (19) of a parasitic element (17), capacitance loading electrodes (24 and 25) and ground electrodes (26 and 27) are formedarranged opposite to each other. In the opposing portions, electric-field deflectors (31, 32, 37, and 38) are formedprovided, thus reducing the electric-field coupling between the feeding element (16) and the parasitic element (17).

Abstract: A surface mount type antenna includes a loop-shaped fed radiation electrode provided on a substrate, and a non-fed radiation electrode is arranged close to the fed radiation electrode with a gap provided therebetween. One end side of the non-fed radiation electrode is grounded, and the other end side is an open end. A signal is sent to the non-fed radiation electrode from the fed radiation electrode by electromagnetic coupling to perform a resonant operation. The fed radiation electrode and the non-fed radiation electrode generate a double-resonant state. The double resonance extends the frequency band. When the fed radiation electrode and the non-fed radiation electrode are provided on the substrate to define an antenna, the size of the antenna is greatly reduced.

Abstract: An antenna-electrode structure includes a feeding radiant-electrode and a grounded portion arranged such that an open-end of the feeding radiant-electrode defines a capacitance to the grounded portion therebetween, and a non-feeding radiant-electrode arranged to electromagnetically couple the feeding radiant-electrode. The non-feeding radiant electrode is arranged such that an open-end thereof defines a capacitance to the grounded portion therebetween to produce a dual-frequency resonance state together with the feeding radiant-electrode. In response to a signal supplied from a signal-supply source, the feeding radiant-electrode performs an antenna action and the non-feeding radiant-electrode in turn performs an antenna action by signal transmission from the feeding radiant-electrode, such that by being excited from these actions, the grounded portion also performs an antenna action.

Abstract: An antenna apparatus includes a dielectric base, and a plurality of feeding-radiating elements having different resonance frequencies, each including a feeding electrode and a radiating electrode which are disposed on surfaces of the base. A stub with a common feeding point is disposed on a mounting substrate which supports the base. The feeding electrodes of the feeding-radiating elements are connected to matching points of the stub, thereby achieving impedance matching for each of the feeding-radiating elements.

Abstract: A wireless communication apparatus includes a casing made of a dielectric material. An antenna including a feed element and first and second parasitic elements is provided in the casing. The feed element includes first and second feed radiation plates. A parasitic radiation plate of the first parasitic element is located near the first radiation plate, and a parasitic radiation plate of the second parasitic element is located near the second feed radiation plate. The amount of coupling between the feed element and the first and second parasitic elements is adjusted based on the relative permittivity of the casing. The feed element and the first parasitic element perform multi-resonance in the same frequency band as the resonance frequency of the first feed radiation plate. The feed element and the second parasitic element perform multi-resonance in the same frequency band as the resonance frequency of the second feed radiation plate.

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 mount type antenna includes a loop-shaped fed radiation electrode provided on a substrate, and a non-fed radiation electrode is arranged close to the fed radiation electrode with a gap provided therebetween. One end side of the non-fed radiation electrode is grounded, and the other end side is an open end. A signal is sent to the non-fed radiation electrode from the fed radiation electrode by electromagnetic coupling to perform a resonant operation. The fed radiation electrode and the non-fed radiation electrode generate a double-resonant state. The double resonance extends the frequency band. When the fed radiation electrode and the non-fed radiation electrode are provided on the substrate to define an antenna, the size of the antenna is greatly reduced.

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: A feed radiation electrode including two branched radiation electrodes is provided on the surface of a substrate. Non-feed radiation electrodes are provided on both sides of the feed radiation electrode and near the branched radiation electrodes. The branched radiation electrode and the non-feed radiation electrode are double-resonated in the same frequency band. The branched radiation electrode and the non-feed radiation electrode are double-resonated in the same frequency band which is higher than that of the branched radiation electrode and the non-feed radiation electrode.