Micro-strip double-pass-band filter

Abstract

The invention discloses a micro-strip double-pass-band filter which is respectively applied to a broad-band system and a narrow-band system. The double-pass-band filter is formed on a dielectric substrate and comprises a first resonator, a second resonator, a third resonator, a fourth resonator, a first feeder line, a second feeder line, a first short circuit branch and a second short circuit branch. A three-order interdigital filter is formed by the first feeder line, the second feeder line, the first resonator, the second resonator and the third resonator and a broad-band pass band is generated. A dual-mode filter is formed by the first feeder line, the second feeder line, the first resonator, the third resonator and the fourth resonator and a narrow-band pass band is generated. Parameters of the two pass bands of the double-pass-band filter can be independently adjusted, the pass bands are high in frequency selectivity and isolation, the circuit structure is simple, and performance is good.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a microstrip double-passband filter. Background technique [0002] With the rapid development of modern wireless communication technology, the communication system working in two or more frequency bands at the same time has become a key direction of current research, and the dual-passband system is more widely used. As filter components are crucial components in communication systems, the research on dual-passband filters has also attracted much attention. The microstrip structure has great advantages in miniaturization and low cost, so microstrip dual-passband filters have an important role in the industry. Extensive research. [0003] Among the many design methods of dual-passband filters, two are widely used. One is to use a single resonator with tunable frequency, such as stepped impedance resonator (SIR), etc., so that the obtained filter can be very It is c...

AI Technical Summary

Problems solved by technology

[0003] Among the many design methods of dual-passband filters, two are widely used. One is to use a single resonator with tunable frequency, such as stepped impedance resonator (SIR), etc., so that the obtained filter can be very It is convenient to control the center frequency of each passband, but its bandwidth is difficult to adjust independently; the second method is the resonator combination method, which is to combine different resonators in a certain way, so that each group of resonators produces a passband , by adjusting different resonator parameters to control the center frequency and passband of its corresponding bandwidth, the filter obtained in this way is often complex in structure and large in size

[0004] In the existing technology, the dual-passband filter generally has the problems that the passband parameters cannot be adjusted independently, the bandwidth is narrow, and the insertion loss is large.

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