Asymmetric DGS (Defected Ground Structure) structure cascaded filter

Abstract

The invention relates to an asymmetric DGS (Defected Ground Structure) structure cascaded filter, belonging to the field of microwave devices. A T-shaped defected grounding structure asymmetric to a microstrip line is etched on a rectangular dielectric slab as an asymmetric T-shaped DGS structure of a single unit, and the asymmetric T-shaped DGS structures of two or three single units are cascaded in parallel to form the filter. Compared with the traditional dumbbell and T-shaped DGS structures, the asymmetric DGS structure filter can effectively inhibit secondary harmonic waves and third harmonic waves of the microwave devices in a specific frequency range, and the volume of the filter is not increased greatly. Multiple symmetric and asymmetric DGSs can be cascaded, and the cascaded product can obtain higher inhibition action on wide stopband of secondary harmonic waves and third harmonic waves of the microwave devices.

Description

technical field [0001] The invention belongs to the field of microwave components, and in particular relates to an asymmetrical DGS structure cascaded filter used in a communication system. Background technique [0002] In communication systems and electronic equipment, filters are widely used, especially in wireless communication systems and microwave equipment, it is one of the indispensable microwave components. Using the DGS structure (Defected Ground Structure, defined as "defective ground structure") to further define the filter also defines its structure and performance characteristics. The filter is the throat of the communication system. It can realize functions such as image elimination, harmonic suppression, parasitic filtering and channel selection. It can selectively allow signals with certain frequencies to pass through, suppress unnecessary frequency signals, and ensure accurate communication. No interference, safe and reliable electromagnetic environment and...

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Problems solved by technology

[0014] The technical problem to be solved by the present invention is that suppressing the harmonics formed due to the nonlinear characteristics of the circuit is a difficult problem in microwave circuit design. For the defective grounding structure in the existing microwave design field, or there is a suppression frequency point that only A single point, or in an asymmetric DGS structure, although the suppression effect on two frequency points can be obtained, the bandwidth of the obtained suppression curve is still very narrow, the suppression depth is not enough, and the waveform shape of the S parameter is not ideal enough

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