Abstract: An antenna device and a mobile radio apparatus using the same antenna device are disclosed. The antenna device includes a ground plate of which short side has a length “a”, a first and a second antenna elements, and a switching circuit. The switching circuit selects whether the first and the second antenna elements are used as a balanced type of antenna or the first antenna is used as an unbalanced type of antenna and the second antenna element is left as a passive element. Assume that wavelength ?1 corresponds to the fundamental frequency of the antenna elements, and wavelength ?2 corresponds to the max. frequency in a usable frequency band, and the antenna elements have electrical length ? which is set at ?1/4. Assume that the first antenna element has physical length L1 smaller than electrical length ?, and the second antenna element has physical length L2. The sum of L1 and L2 is shorter than the short side length “a”, and a half of “a” is smaller than ?2/4.

Abstract: A small multilayer filter, in which a phase shifter may be constituted without increasing overall size of the filter. The overall size may be reduced without deteriorating the characteristics. Above the open end of a plurality of strip lines 4A provided on a dielectric layer 4, a coupling sector 3A of input/output pattern is placed to face it with a dielectric layer 3 interposed. An inductance L1, L2 is formed by connecting a side electrode 7A, 7B with a continuity sector 3B of input/output pattern; and said side electrode 7A, 7B with an input electrode 8A, output electrode 8B, respectively, by means of an electrode pattern 5A.

Abstract: A small multilayer filter, in which a phase shifter may be constituted without increasing overall size of the filter. The overall size may be reduced without deteriorating the characteristics. Above the open end of a plurality of strip lines 4A provided on a dielectric layer 4, a coupling sector 3A of input/output pattern is placed to face it with a dielectric layer 3 interposed. An inductance L1, L2 is formed by connecting a side electrode 7A, 7B with a continuity sector 3B of input/output pattern; and said side electrode 7A, 7B with an input electrode 8A, output electrode 8B, respectively, by means of an electrode pattern 5A.

Abstract: A small multilayer filter, in which a phase shifter may be constituted without increasing overall size of the filter. The overall size may be reduced without deteriorating the characteristics. Above the open end of a plurality of strip lines 4A provided on a dielectric layer 4, a coupling sector 3A of input/output pattern is placed to face it with a dielectric layer 3 interposed. An inductance L1, L2 is formed by connecting a side electrode 7A, 7B with a continuity sector 3B of input/output pattern; and said side electrode 7A, 7B with an input electrode 8A, output electrode 8B, respectively, by means of an electrode pattern 5A.

Abstract: A small multilayer filter, in which a phase shifter may be constituted without increasing overall size of the filter. The overall size may be reduced without deteriorating the characteristics. Above the open end of a plurality of strip lines 4A provided on a dielectric layer 4, a coupling sector 3A of input/output pattern is placed to face it with a dielectric layer 3 interposed. An inductance L1, L2 is formed by connecting a side electrode 7A, 7B with a continuity sector 3B of input/output pattern; and said side electrode 7A, 7B with an input electrode 8A, output electrode 8B, respectively, by means of an electrode pattern 5A.

Abstract: A dual-band multilayer bandpass filter having a first filter unit (18) for filtering a first signal having a first frequency and a second filter unit (19) for filtering a second signal having a second frequency. First and second filter units are arranged in stacked ceramic layers. A first blocking element (20a, 20b; 25a, 25b; 25a', 25b'; 46a, 46b) is coupled to the first filter unit (18) for blocking the second signal from being applied to the first filter unit (18). A second blocking element (21a, 21b; 26a, 26b; 25c, 25d; 27a, 27b) is coupled to the second filter unit (19) for blocking the first signal from being applied to the second filter unit (19).