Abstract: A resonator includes: interdigital transducer (IDT) including first electrode including first base on piezoelectric substrate and extended in reference direction, and first protrusions connected to the first base and extended in direction intersecting with the reference direction, and second electrode including second base on the piezoelectric substrate and extended in the reference direction, and second protrusions connected to the second base and extended in direction intersecting with the reference direction, each of the second protrusions extended to have one of the first protrusions inserted between the second protrusion and another second protrusion adjacent to the second protrusion, wherein a width of each of first specific protrusions included between one end of the IDT and first position at first distance from the one end, among the first protrusions and the second protrusions, decreases from first specific protrusion closest to the first position toward first specific protrusion closest to the one e

Abstract: A resonator includes: interdigital transducer (IDT) including first electrode including first base on piezoelectric substrate and extended in reference direction, and first protrusions connected to the first base and extended in direction intersecting with the reference direction, and second electrode including second base on the piezoelectric substrate and extended in the reference direction, and second protrusions connected to the second base and extended in direction intersecting with the reference direction, each of the second protrusions extended to have one of the first protrusions inserted between the second protrusion and another second protrusion adjacent to the second protrusion, wherein a width of each of first specific protrusions included between one end of the IDT and first position at first distance from the one end, among the first protrusions and the second protrusions, decreases from first specific protrusion closest to the first position toward first specific protrusion closest to the one e

Abstract: Disclosed is a miniaturized duplexer having a good isolation characteristic. A duplexer having a high band side filter and a low band side filter that are each formed in a ladder-type filter provided on a common piezoelectric substrate is provided with a first elastic wave resonator to be included in one of these filters, a second elastic wave resonator to be included in the other of the filters, and a first additional grating reflector provided between these resonators to reflect an elastic wave leaked from a grating reflector of the first elastic wave resonator, and in which an additional grating reflector is not provided on a side opposite to the second elastic wave resonator in the first elastic wave resonator.

Abstract: A duplexer formed on a piezoelectric substrate includes a low band side filter and a high band side filter, and has an improved isolation characteristic in a pass frequency band of the high band side filter. Transmission and reception of signals are respectively performed from either of the low band side filter and the high band side filter and the other filter with respect to an input/output port. Series arms and parallel arms each formed of an elastic wave resonator form the low band side filter. A shield electrode is disposed close to either of the input/output port and a low band side filter port, and is grounded for capacitive coupling with same.

Abstract: To provide a duplexer which is small in size and excellent in separation characteristic of transmission/reception signals.

Abstract: Disclosed is a miniaturized duplexer having a good isolation characteristic. A duplexer having a high band side filter and a low band side filter that are each formed in a ladder-type filter provided on a common piezoelectric substrate is provided with a first elastic wave resonator to be included in one of these filters, a second elastic wave resonator to be included in the other of the filters, and a first additional grating reflector provided between these resonators to reflect an elastic wave leaked from a grating reflector of the first elastic wave resonator, and in which an additional grating reflector is not provided on a side opposite to the second elastic wave resonator in the first elastic wave resonator.

Abstract: To improve an isolation characteristic in a pass frequency band of a high band side filter 12 in a duplexer including a low band side filter 11 and the high band side filter 12. In a low band side filter 11 in a duplexer formed on a piezoelectric substrate 10 and in which transmission and reception of signals are respectively performed from either of the low band side filter 11 and the high band side filter 12 and the other filter with respect to an input/output port 14, series arms and parallel arms each formed of an elastic wave resonator 5 form the low band side filter 11, and a shield electrode 50 extending to a position close to at least either of the input/output port 14 and a low band side filter port 15 and grounded is disposed.

Abstract: To provide a duplexer which is small in size and excellent in separation characteristic of transmission/reception signals.

Abstract: A halogenated flame retardant for a thermoplastic resin with carbonyl linkages in the main chain such as polyethylene terephthalate or polybutylene terephthalate is obtained by the modification of a brominated bisphenol A epoxy resin optionally advanced with brominated bisphenol A by reaction of the epoxy groups with a C1-C8 alcohol such as methanol or butanol to the extent that the ratio of unmodified epoxy groups to alcohol-modified epoxy groups is from 2/1 to 1/2.