Resonator, filter, duplexer, and communication device

摘要

A resonator, a filter, and a duplexer are provided which are capable of very effectively suppressing the power loss caused by the edge effect, and which allow a great reduction in the overall size to be achieved. Also, a communication device including the above-mentioned filter or duplexer is provided. A ground electrode (3) is formed over the bottom surface of a dielectric substrate (1), and a multiple spiral line pattern (21) is formed on the top surface thereof. A radial line pattern (22) is further formed on this surface with an insulation layer interposed therebetween. By thus disposing the radial pattern (22) adjacently to the multiple spiral resonator constituted of the above-mentioned multiple spiral line (21), an electrostatic capacitance is added to the multiple spiral resonator. This reduces the occupation area of the resonator on the substrate, and improves the loss reduction effect.