A Miniaturized Terahertz Low-Pass Filter

Abstract

The invention discloses a miniaturized terahertz low-pass filter, which belongs to a filter, in particular to a terahertz low-pass filter. The present invention introduces the split ring (SRR) structure into the low-pass filter design, and improves it to realize the series-parallel connection of the SRR structure to finally realize a wide high-frequency suppression stop band, and the low-pass filter realized with the SRR structure shows good low-pass filter characteristics. Because the SRR structure can control the passband of the filter by adjusting few variables, and the used line width is consistent and adjustable, which reduces the difficulty of design and processing. Compared with the low-pass filter composed of step structure and band gap energy structure, the split-ring low-pass filter has smaller size and wider stop band under the same stop-band suppression characteristics.

Description

technical field [0001] The invention belongs to a filter, in particular to a terahertz low-pass filter. Background technique [0002] In recent years, with the development of the terahertz frequency band, terahertz low-frequency radar systems and radiometer systems based on solid-state terahertz technology have emerged. In these systems, terahertz frequency multipliers and mixers that can develop power signals from microwave frequency bands to terahertz frequency bands are particularly important. The advantages of these solid-state terahertz devices, such as compact structure, light weight, high reliability, and low cost, are not available in other terahertz devices, so solid-state terahertz devices have attracted much attention in the field of terahertz. When designing solid-state terahertz devices, terahertz low-pass filters are unavoidable unit circuits. In the terahertz frequency multiplier and mixer circuit, the terahertz low-pass filter is responsible for screening t...

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Problems solved by technology

[0003] In the solid-state terahertz circuit, because the wavelength is very short, the size of the cavity and the substrate of the circuit are very small, basically in the order of submillimeters. Therefore, the microstrip line in the microstrip line / suspension microstrip line circuit The maximum line width is limited, which limits the design of impedance lines. In addition, the minimum processing accuracy limits high impedance lines. Therefore, the design of step-type high-low impedance low-pass filters in the terahertz frequency band is subject to many restrictions. Moreover, the multi-section step-type high and low impedance filter has disadvantages such as too long length and insufficient square coefficient.

Compared with the step-type low-pass filter, the low-pass filter composed of the bandgap energy structure can reduce the size of the filter, and has better stop-band suppression characteristics, but its stop-band width is relatively small, which cannot meet the needs of broadband circuits. In addition, the 50 ohm impedance line width of the microstrip line / suspended microstrip line in the terahertz frequency band is very small, and it is difficult to realize the bandgap energy structure under the existing processing accuracy.

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