Abstract: An antenna intended to be used in a small and foldable radio device and a radio device which has an antenna according to the invention. The radiating element (120) in the antenna is a conductor having an outline shaped substantially like a rectangle and defining a plane which is perpendicular to the ground plane (GND) situated on the circuit board (111) of the radio device. The radiating element is so narrow that it fits inside the foldable device in the perpendicular position. The element is connected to the radio device only by its feed point (F). Resonating frequencies of the element can be arranged in desired locations besides by shaping the element, also by means of discrete components (L, C). The matching of the antenna is easily arranged by providing an appropriate distance between the radiating element and ground plane. In an operating situation, an antenna gain is achieved which is considerably higher than that of a PIFA of equal height.

Abstract: An antenna intended to be used in a small-sized and flat radio device, and to a radio device which has an antenna according to the invention. The base element of the antenna is a monopole-type conductor (110) internal to the device. This conductor may be designed such that the harmonic nearest to the fundamental resonating frequency can be utilized in providing an upper operating band. In addition to the base element the antenna structure comprises a parasitic element (120) which functions as both an auxiliary radiator and antenna matching element. Matching is optimized using an inductive component (125) which connects the parasitic element to signal ground. The antenna gain achieved is considerably higher than that of known antenna structures occupying the same space (h), and the antenna matching is improved, compared to known internal monopole antennas.

Abstract: The invention relates to a multiband antenna which finds utility particularly in mobile stations. The antenna structure includes a PIFA-type antenna positioned inside the covers of a mobile station, which antenna includes a slot radiator (231). In the planar element there is a second slot (232) so that, viewed from a feed point (F), two radiating conductive branches (B1, B2) of different lengths are formed. Each of the three radiators has a separate operating band of its own. The structure also includes a whip element (211) movable with respect to the PIFA part. When the whip element is pulled out, its lower end is galvanically coupled with the shorter branch of the planar element, with its relatively narrow side branch (B12). The whip enhances the operation of the antenna especially in the lowest operating band. The influence of the pulled-out whip on the location of the uppermost operating band is compensated for by a third slot (233) in the planar element.

Abstract: An internal planar antenna for small radio apparatuses. The ground plane (310) of the planar antenna is shaped such that it improves the matching of the antenna. The shaping may be done by means of one or more slots (315, 316) in the ground plane. The slot suitably changes the electrical length of the ground plane as viewed from the short-circuit point (S) so that the ground plane will function as a radiator in an operating band of the antenna. Also the slot (331) in the ground plane can be arranged to function as an additional radiator in an operating band of the antenna. Antenna gain will increase as the matching is improved, and the upper band of a dual band antenna, for example, can be made broader.

Abstract: A double-action antenna structure includes, e.g. a PIFA-type antenna inside the casing of a mobile station, a coupling element and a moveable whip element. The coupling element is a relatively small conductive element between the radiating plane and ground plane of the PIFA, galvanically isolated from the radiating plane and ground plane. When the whip element is retracted, it has no significant coupling to the PIFA parts. When the whip element is extended, its lower end is galvanically connected to the coupling element so that a significant electromagnetic coupling is established between the whip element and the radiating plane of the PIFA. Thus the whip element is fed through the PIFA without being in galvanic contact with it. The coupling element further provides for the matching of the whip element. The internal and external antennas may be designed and optimized relatively independently of each other.

Abstract: Internal planar antenna especially applicable to mobile communication devices. A PIFA-type planar antenna is fed coaxially-like. This means that the feed conductor (321) of a radiating plane (310) is surrounded by a shield conductor (322) galvanically connected to the ground plane (GND) for the length between these planes. The shield conductor at the same time serves as a short circuit conductor for the antenna. The antenna is matched by means of a matching slot (317) going between the connection points of the feed and short circuit conductors, and/or of the shape of the short circuit conductor. A feed arrangement at issue increases antenna gain without increasing the SAR value of the antenna.

Abstract: An arrangement for enhancing electrical isolation between antennas in antenna structures comprising at least two antennas, and a radio device applying the arrangement. The interfering antenna comprises components causing substantial degradation in radiation characteristics in the operating band of another antenna. For example, a PIFA (310) may comprise, instead of a short-circuit conductor, a conductive structure (312, 313, 314) having a parallel resonance in the operating band of another antenna (320). Mutual interference of radio parts using separate antennas can be made relatively small without electrical isolation arrangements between antenna elements. Moreover, the invention makes antenna filter design easier and reduces disadvantages caused by antenna filters.

Abstract: The invention relates to double-action antenna structures. The structure comprises an antenna inside the covering of a mobile station, a switch (SW) and a whip, element (240) movable in relation to the former two. The internal antenna comprises two elements the first of which (220) is connected to the feed conductor (202) of the whole antenna structure and the second to the signal ground (203, 210). When the whip element is retracted, the said switch galvanically interconnects the elements of the internal antenna. Thus only the internal antenna functions and the whip has no practical significance. When the whip element is extended, its lower end disconnects, by means of the switch, the elements of the internal antenna, and the whip element itself is connected in series with the first element. Thus, a radiating element is provided by the series connection (240, 220) of the whip and the first element, and the shorted element (230) of the internal antenna has no practical significance.

Abstract: The invention pertains to an antenna construction of at least two frequency bands comprising at least a whip antenna. A dielectric block (33) with a relatively high permittivity is installed into the whip antenna (32) at a location in which there is a voltage maximum at a harmonic of the basic resonance frequency of the antenna. The dielectric medium shifts the harmonic in question downwards. The arrangement is realized in such a manner that the basic resonance frequency of the whip antenna falls on the operating frequency band of one network, and the harmonic in question falls on the operating frequency band of a desired second network. The construction may further comprise a PIFA antenna (34) the operating frequency of which is the same as the upper operating frequency of the whip antenna. Thus the degradation of the function of the PIFA that can be caused by the user's hand will not substantially degrade the connection since the whip, too, operates in the operating frequency band of the PIFA.

Abstract: The invention relates to a multiband antenna which finds utility particularly in mobile stations. The antenna structure includes a PIFA-type antenna positioned inside the covers of a mobile station, which antenna includes a slot radiator (231). In the planar element there is a second slot (232) so that, viewed from a feed point (F), two radiating conductive branches (B1, B2) of different lengths are formed. Each of the three radiators has a separate operating band of its own. The structure also includes a whip element (211) movable with respect to the PIFA part. When the whip element is pulled out, its lower end is galvanically coupled with the shorter branch of the planar element, with its relatively narrow side branch (B12). The whip enhances the operation of the antenna especially in the lowest operating band. The influence of the pulled-out whip on the location of the uppermost operating band is compensated for by a third slot (233) in the planar element.

Abstract: The invention relates to double-action antenna structures. The structure comprises an antenna inside the covering of a mobile station, a switch (SW) and a whip element (240) movable in relation to the former two. The internal antenna comprises two elements the first of which (220) is connected to the feed conductor (202) of the whole antenna structure and the second to the signal ground (203, 210). When the whip element is retracted, the said switch galvanically interconnects the elements of the internal antenna. Thus only the internal antenna functions and the whip has no practical significance. When the whip element is extended, its lower end disconnects, by means of the switch, the elements of the internal antenna, and the whip element itself is connected in series with the first element. Thus, a radiating element is provided by the series connection (240, 220) of the whip and the first element, and the shorted element (230) of the internal antenna has no practical significance.

Abstract: The invention relates to a planar antenna structure in small-sized radio apparatus. A layer of dielectric material, the dielectric constant of which is relatively high, is arranged outwards of the plane of the outer surface of the radiating element of a planar inverted F antenna, or PIFA. The layer is located so as to cover at least the areas in which the electric field is the strongest when the antenna resonates. In the case of dual-band antenna, the slot in the radiating element is made advantageously so wide that the effect of the coupling between the branches (A1, A2) of the element is small. An antenna according to the invention can be made smaller in size and at least as good in its electrical characteristics as a corresponding prior-art antenna. Alternatively, the electrical characteristics of the antenna can be substantially improved without making the size of the antenna bigger.

Abstract: The invention relates to double-action antenna structures. The structure comprises e.g. a PIFA-type antenna inside the casing of a mobile station, a coupling element and a whip element movable in relation to the former two. The coupling element (240) is a relatively small conductive element between the radiating plane (220) and ground plane (210) of the PIFA, galvanically isolated from the radiating plane and ground plane. When the whip element (230) is retracted, it has no significant coupling to the PIFA parts. When the whip element is extended, its lower end (231) is galvanically connected to the coupling element so that a significant electromagnetic coupling is established between the whip element and the radiating plane of the PIFA. Thus the whip element is fed through the PIFA without being in galvanic contact with it. The coupling element further provides for the matching of the whip element.

Abstract: A planar antenna comprises a planar radiating element (600) formed of a conductive area confined by a substantially continuous border line. The conductive area is split by a gap which divides the planar radiating element into a first branch and second branch such that both the first and the second branch have an outermost end. The gap has a head end on said substantially continuous border line and a tail end within the conductive area. At its head end (601) the gap has a certain first direction and at another point (603) a certain second direction which differs from the first direction by more than 90 degrees when the directions are defined along the gap from the head end towards the tail end. The outermost end of the second branch, confined by the gap, is located within the continuous border line, surrounded by the first branch.

Abstract: The invention relates to an antenna structure to be installed inside small-sized radio apparatus. A conventional PIFA-type structure is extended such that on top of the ground plane (210) there will be instead of one at least two radiating planes (220, 230) on top of each other. There is between them dielectric material (240) to reduce the size of the lower radiator and to improve the band characteristics. Likewise, there is dielectric material (250) on top of the uppermost radiating plane so as to bring one resonance frequency of the antenna relatively close to another resonance frequency in order to widen the band. Advantageously the radiating planes are in galvanic contact (203) with each other. The invention accomplishes a greater increase in the antenna bandwidth as compared to that achieved by placing the only radiating plane at a distance from the ground plane equal to that of the upper radiating plane according to the invention.

Abstract: The invention relates to planar antennas the structural components of which include a parasitic element. The antenna structure comprises a PIFA-type structure (230, 210, 202) to be placed inside the covers of a mobile station. The PIFA is fed parasitically e.g. through a conductive strip (240) placed on the same insulating board. The feed conductor (203) of the whole antenna structure is in galvanic contact with this feed element; a short-circuit point the feed element doesn't have. The feed element (240) also serves as an auxiliary radiator. The resonance frequencies of the antenna elements or their parts are arranged according to need so as to overlap, to be close to each other or to be relatively wide apart. The structure may also comrise a whip element in connection with the feed element. According to the invention, a relatively simple structure provides a reliable dual resonance and, hence, a relatively wideband antenna when the resonances are close to each other.

Abstract: A PIFA structure has a first operating frequency and a second operating frequency. It comprises a planar radiating element (801, 1002, 1101, 1203) which is a conductive area confined by a substantially continuous border line divided by a non-conductive slot (802). The slot has a first end on said substantially continuous border line and a second end within the conductive area. The planar radiating element comprises a feedpoint (803, 1206) and ground contact (804, 1208) near the first end of the slot so that the electrical length of the conductive area divided by the slot, measured at the feedpoint, equals a quarter of the wavelength at the first operating frequency and the electrical length of the slot equals a quarter of the wavelength at the second operating frequency.

Abstract: The invention relates to dual mode antennas particularly suitable for mobile stations. The antenna structure comprises an antenna (211, 201, 202, 212) of the PIFA type which is located within the covers of the mobile station, and a whip element (220) which is movable relating to the PIFA antenna. The PIFA can be a single band or a dual band antenna. When the whip element is extracted its lower end (222) forms a galvanic or capacitive coupling with the radiating element (211) of the PIFA. If the PIFA is a single band antenna the extracted whip element substantially changes the resonant frequency of the PIFA, so that the whip is left as the radiating element at the operating band. If the PIFA is a dual band antenna, then an extracted whip alone, or the whip and the planar element of the PIFA together, functions as the radiating element at one operating band, and at the other operating band the planar element of the PIFA operates as the radiating element.