High-selectivity wide-stopband balance filter based on slot line

Abstract

The invention belongs to the technical field of balance filters, and discloses a high-selectivity wide-stopband balance filter based on a slot line. The high-selectivity wide-stopband balance filter comprises a microstrip, a dielectric substrate and a conductive layer which are arranged successively. A slot line is etched on the conductive layer to form a passband selection module and a stopband suppression module. The passband selection module comprises two open ring resonators symmetrically arranged in a horizontal direction. The coupling end of one open ring resonator serves as the signal feed-in end of the passband selection module. The coupling end of the other open ring resonator serves as the signal feed-out end of the passband selection module. The stopband suppression module comprises two slot line [pi]-type networks symmetrically arranged in the vertical direction, wherein one slot line [pi]-type network is connected to the signal feed-in end of the passband selection module,and the other slot line [pi]-type network is connected to the signal feed-out end of the passband selection module. The high-selectivity wide-stopband balance filter achieves a wide stopband and highpassband selectivity by using a second-order resonant circuit composed of the slot line [pi]-type networks and the two slot line open ring resonators.

Description

technical field [0001] The invention belongs to the technical field of balanced filters, and more specifically relates to a slot-line-based high-selectivity wide-stop band balanced filter. Background technique [0002] With the rapid development of radio frequency communication systems, people have higher and higher requirements for the anti-interference ability and noise suppression level of the circuit. As the main effective means to solve this problem, the balanced circuit has received more attention and research. Among them, the balanced filter is the most basic device in the balanced circuit. A competitive balanced filter should be able to efficiently pass the desired differential-mode signals while effectively rejecting common-mode signals in the passband. A new type of balanced filter with high selectivity and wide stopband characteristics can better meet the needs of communication systems, and it is also a research trend. [0003] In order to obtain high selectivi...

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Problems solved by technology

[0008] Aiming at the defects of the prior art, the purpose of the present invention is to provide a slot-based high-selectivity wide stop-band balanced filter, which aims to solve the problem of differential bands realized by microstrip odd-even mode circuits or conventional slot-line architectures in the prior art. When the pass-through transmission characteristics and wide-band common-mode rejection characteristics are used, the differential transmission cannot simultaneously achieve a sufficiently wide suppression range in the stopband and high selectivity in the passband

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