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 comprises a high-frequency low-pass filter (200) The filter utilizes distributed capacitance and inductance elements (221-227) which are realized using a homogeneous and relatively rigid conductive part (220). The conductive part is located mainly air-insulated in an enclosed metal housing (210) which serves as a ground conductor for the signal. The housing comprises conductive partition walls (212-214) to prevent coupling between adjacent capacitive elements. The advantages of the construction include good power handling capacity, good breakdown characteristics, small losses and low manufacturing costs, among other things.

Abstract: The invention relates to a high-pass filter realized in a conductive casing by means of mechanical structural elements, which filter is suitable for signal processing especially at microwave frequencies. In the casing (201, 202, 203) there are in series rigid conductive elements (2IN, 210, 220, 230, 2OUT) separated from each other. Between successive elements there is capacitance that can be adjusted within certain limits, if necessary. The insulating material between the elements is air or plastic, for example. At least some of the conductive elements involve a conductor (214, 224) less than half a wavelength long, short-circuited at the opposite end to the casing. This together with the casing connected to the signal ground provides a transmission line which, looking from the conductive element, is inductive at the operating frequencies.

Abstract: The invention relates to a bandpass filter comprised of coaxial resonators. On the side of a resonator chain (200) which makes the filter there is provided an additional equalizing resonator (EQ1) which is coupled to a resonator (R3) in the chain. The resonance frequency of the equalizing resonator and the coupling with the rest of the filter are arranged so that attenuation increases at a point corresponding to an original attenuation minimum. Thereby it follows that attenuation variation in the whole pass band decreases. Response equalization can be further enhanced by providing a second equalizer (EQ2) affecting a band beside the first one. Using the structure according to the invention, a decrease of a certain magnitude in the pass band attenuation variation of a bandpass filter can be achieved with a smaller increase in the number of resonators than in known structures. Moreover, the production costs caused by the additional structure are relatively small.

Abstract: A multiband antenna applicable as an internal antenna in small mobile terminals especially. The antenna (200) is a PIFA placed inside the housing of a mobile station with at least two operating bands. A first resonance falling into a lower operating band is produced by means of a radiating conductive pattern (B21) in planar element (220). To improve the characteristics of the antenna in the upper operating band the planar element further comprises a slot (232) which goes between the feed point (F) and the short-circuit point (S) of the antenna. The radiator provided by this slot can be considered a quarter-wave slot radiator or a half-wave loop radiator. The PIFA further may have another radiator, which resonates in the upper operation band. By means of said slot the upper operating band of an antenna can be widened or the radiation in the horizontal plane in the upper operating band can be made more effective.

Abstract: The invention relates to an antenna structure (400) to be placed inside in particular small radio apparatus. A conventional PIFA-type structure is extended by arranging a structural part (415) adding to the capacitance between the radiating plane (420) and ground plane (410) relatively close to the feed point (F) of the antenna. The structural component may be a projection extending from the radiating plane towards the ground plane or vice versa. An advantage of the invention is that it achieves a significant increase in the antenna bandwidth without increasing the size of the antenna. Another advantage of the invention is that the structure according to it is simple and the increase in the manufacturing costs is relatively low.

Abstract: A method for attaching a part to a body of a resonator, which body is made by the process of extruding. In a pushing part (ES) of an extrusion machine is made a recess, which is shaped like a portion of the surface of the additional object. An additional object (320), such as a portion of the inner conductor of a resonator, is inserted prior to extrusion in said recess so that said portion of the surface of the additional object rests tightly against the surface of the recess and the rest of the surface of the additional object remains free. In the extrusion stage, the pushing part with the additional object is pressed (F) against a bloom of a resonator body whereby the material (31c) of the bloom is pressed tight against the free surface of the additional object. When the pushing part is retracted the additional object remains attached to the body 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 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 dielectric antenna, particularly suited to portable radio devices. The feed conductor (231) of the antenna is shaped so that it at the same time in itself serves as a radiator in the same frequency range as the dielectric resonator (220) of the antenna. The resonance frequencies of the feed conductor and the dielectric resonator are advantageously arranged to be so near to each other that there is formed a united operation band. The feed conductor is advantageously located on a surface (223) of the dielectric element. The structure may also include parasitic conductors. For the antenna according to the invention, there is obtained a larger bandwidth than for corresponding antennas of the prior art. Moreover, the air gaps between the feed conductor and the dielectric element are avoided, as well as resulting changes in the electric properties.

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 a multiband antenna structure suitable for mobile stations in particular. The radiating elements of the antenna include not only a helix (210) but also the joining piece (220) that attaches the helix to the apparatus. The helix is shaped such that the distance between its conductor turns varies. The electrical length of the joining piece is increased e.g. by means of a conductive projection (226) that remains within the covering of the apparatus. By suitably dimensioning the parts, at least five of the resonances that the helix and joining piece have together and separately are arranged at useful points on the frequency scale. The structure according to the invention is despite the several bands simple and relatively low in production costs.

Abstract: The invention relates to a method for tuning dielectric antennas designed for operation especially in the microwave range, and an antenna structure. An antenna is tuned by removing material (211) from a dielectric block (210) located between conductive elements, whereby the resonance frequency of the antenna increases. The conductive elements (220, 230) on opposing surfaces of the dielectric block are advantageously shaped identical and located symmetrically with respect to each other so that the tuning of the antenna will not affect the other electrical characteristics of the antenna apart from the resonance frequency. With the method according to the invention there is no risk of producing conductive chips resulting from the working of metallic elements, the tuning of the antenna becomes accurate, and structural faults in the medium will be automatically compensated for.

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: The invention comprises a filter consisting of resonators (330, 320, . . . ) with a conducting housing, particularly to be used in networks operating on microwave frequencies. The couplings between the resonators are realised outside the conducting filter housing with the aid of a printed board (310) over a wall (306) of the housing. For a particular coupling a conductor strip (311) extending from one resonator to another is formed on the printed board, and openings (335, . . . ) are made in the resonator walls at the ends of the strips. In order to strengthen the coupling a coupling element (343) extending into the resonator cavity can be fastened as an extension of the strip. The filter connectors (301, . . . ) are also fastened to the printed board. The open filter housing (305) and the inner conductors (331, 341, . . . ) or the resonators can be made as a homogenous body. The manufacturing costs and the tuning costs of a filter according to the invention are relatively low.

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 a high-pass filter realized in a conductive casing by means of mechanical structural elements, which filter is suitable for signal processing especially at microwave frequencies. In the casing (201, 202, 203) there are in series rigid conductive elements (2IN, 210, 220, 230, 2OUT) separated from each other. Between successive elements there is capacitance that can be adjusted within certain limits, if necessary. The insulating material between the elements is air or plastic, for example. At least some of the conductive elements involve a conductor (214, 224) less than half a wavelength long, short-circuited at the opposite end to the casing. This together with the casing connected to the signal ground provides a transmission line which, looking from the conductive element, is inductive at the operating frequencies.

Abstract: The invention relates to a bandpass filter comprised of coaxial resonators. On the side of a resonator chain (200) which makes the filter there is provided an additional equalizing resonator (EQ1) which is coupled to a resonator (R3) in the chain. The resonance frequency of the equalizing resonator and the coupling with the rest of the filter are arranged so that attenuation increases at a point corresponding to an original attenuation minimum. Thereby it follows that attenuation variation in the whole pass band decreases. Response equalization can be further enhanced by providing a second equalizer (EQ2) affecting a band beside the first one. Using the structure according to the invention, a decrease of a certain magnitude in the pass band attenuation variation of a bandpass filter can be achieved with a smaller increase in the number of resonators than in known structures. Moreover, the production costs caused by the additional structure are relatively small.