Abstract: A dielectric antenna duplexer used in a high frequency radio device such as a portable telephone, and a dielectric filter for forming the duplexer of the SIR (stepped impedance resonator) composed by cascade connection of first transmission lines having one end grounded and second transmission lines having one end open and lower in characteristic impedance than in the first transmission lines, first transmission lines and second transmission lines are individually coupled in electromagnetic field, thereby forming an antenna duplexer and a dielectric filter of small insertion loss, high bandwidth selectivity, excellent band pass characteristic, and low cost.

Abstract: An integrated component providing the function of both a conventional directional coupler and a low-pass filter having two attenuation poles at a specified frequency band without changing the line length. Stub lines are connected to both ends of a main transmission line of a directional coupler. A frequency of the attenuation poles is adjustable by characteristic impedance, terminating conditions, and line length of the stub lines.

Abstract: A dielectric laminated filter has a first dielectric laminated block including a first strip line electrode and a second dielectric laminated block including a second strip line electrode and a coupling element, wherein the first and the second dielectric laminated blocks are laminated via a first shield electrode and wherein the first and the second strip lines are connected via a third strip line. This configuration allows the unwanted electromagnetic coupling between a resonator and the coupling element to be neglected, and uses the third strip line electrode to form the first and the second strip line electrodes so that they extend across different layers, thereby enabling the size of the resonator to be reduced. In addition, since the third strip line electrode serves to adjust the filter characteristics, a small high-performance dielectric laminated filter that can be designed easily can be provided.

Abstract: A dielectric antenna duplexer used in a high frequency radio device such as a portable telephone, and a dielectric filter for forming the duplexer of the SIR (stepped impedance resonator) composed by cascade connection of first transmission lines having one end grounded and second transmission lines having one end open and lower in characteristic impedance than in the first transmission lines, first transmission lines and second transmission lines are individually coupled in electromagnetic field, thereby forming an antenna duplexer and a dielectric filter of small insertion loss, high bandwidth selectivity, excellent band pass characteristic, and low cost.

Abstract: A dielectric antenna duplexer used in a high frequency radio device such as a portable telephone, and a dielectric filter for forming the duplexer of the SIR (stepped impedance resonator) composed by cascade connection of first transmission lines having one end grounded and second transmission lines having one end open and lower in characteristic impedance than in the first transmission lines, first transmission lines and second transmission lines are individually coupled in electromagnetic field, thereby forming an antenna duplexer and a dielectric filter of small insertion loss, high bandwidth selectivity, excellent band pass characteristic, and low cost.