Filter device and filter circuit

• Main Authors: ZHANG SHIQIANG, WANG SHENGFU, ZHANG JUNJIE, LI LI, ZHANG NING, YU JIANGTAO, ZHAO ZHENZHEN, ZHOU SHAOBO, SUN CONGKE, LIU EFANG, WANG YANG, ZHANG SHAOHUA, ZHANG KUN
• Format: Patent
• Language: Chinese; English
• Published: 29.11.2022
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

The invention provides a filter device and a filter circuit. The filter device comprises a chip filter, a first FBAR resonator, a second FBAR resonator, a first matching inductor, a second matching inductor and a third matching inductor. The chip filter, the first matching inductor, the first FBAR resonator, the second FBAR resonator and the second matching inductor are sequentially connected in series; one end of the third matching inductor is connected between the first FBAR resonator and the second FBAR resonator, and the other end of the third matching inductor is grounded; the first end of the chip filter is an input end, and the second end is connected with the first matching inductor; the suspended end of the second matching inductor is an output end; the parallel resonant frequency of the first FBAR resonator and the second FBAR resonator is within the frequency range of the stop band near end of the chip filter. According to the invention, the FBAR resonator with a high Q value is arranged, a transmi