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 the structure of a dual-band planar antenna. The radiating element (210) in a planar antenna (200) has a slot consisting of two portions of different widths. One end of the wider portion (216) of the slot is close to the feed point (S) of the radiating element. The narrower portion (217) of the slot starts from a point in the wider portion and extends to the edge of the radiating element. The portions of the slot are advantageously straight. The order of magnitude of the ratio (w1/w2) of the widths of the portions is three. An advantage of the invention is that the bandwidths of a dual-band planar antenna are larger than those of prior-art structures of the same size.

Abstract: An antenna (400; 600) for transmitting and receiving radio-frequency signals comprises a cylindrical coil conductor (601) having a turn A and a turn B and between them other turns. The pitch (x1) of turn A is unequal to the pitch (x2) of said turn B, and the pitches of the other turns between turns A and B are in the order of magnitude between the pitches of turns A and B.

Abstract: The invention relates to a method for attaching an additional object to an object made by the process of extruding, especially a resonator body, and to the structure resulting from the application of the method. A recess is made in the pushing part (ES) of an extrusion machine, which recess is shaped like a portion of the surface of the additional object. The additional object (320), such as a portion of the inner conductor of a resonator, is inserted prior to extrusion in the said recess so that the 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 thus formed.

Abstract: To realize electromagnetic couplings in a high-frequency filter a coupling element (100) comprises a first conductor (201), which has a first end (102) and a second end (103), and an insulating part (101). A portion of the first conductor, located between the first end and second end of the first conductor, is wholly surrounded by the insulating part. On both sides of said portion the first conductor comprises a portion which is outside the insulating part. The insulating part is arranged so as to become attached inside the high-frequency filter.

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 radio device comprises an antenna for transmitting and receiving radio frequency signals. The antenna comprises a radiating antenna element (201, 602, 701) and a dielectric protective casing (202, 703) attached to each other, whereby the dielectric protective casing substantially encloses the antenna element. Further the radio device comprises a protective casing (205) of the radio device for mechanically supporting the radio device and for protecting its electrical components, and a printed circuit board (203) within the protective casing for connecting the electrical components to the radio device and for forming the electrical connections between the components. The antenna is mechanically fastened to the radio device with the aid of counterpart fastening shapes (301, 302, 303, 304, 305, 306, 307, 308) located in the antenna's protective casing and in the radio device's protective casing.

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.