Terahertz miniaturized subharmonic mixer adopting symmetrical folding open-circuit branches

Abstract

The invention relates to a terahertz miniaturized subharmonic mixer adopting symmetrical folded open circuit branches. The terahertz miniaturized subharmonic mixer comprises a microstrip circuit composed of a radio frequency circuit, a local oscillator intermediate frequency duplex circuit, an intermediate frequency output circuit and a diode pair. The radio frequency circuit and the local oscillator intermediate frequency duplex circuit are respectively arranged at two ends of the diode pair; the local oscillator intermediate frequency duplex circuit is internally provided with a band elimination filter with a symmetrical folding open circuit branch structure, and the band elimination filter with the symmetrical folding open circuit branch structure is used for blocking a signal with a corresponding frequency and allowing a signal with another frequency to be transmitted at the same time; and the intermediate-frequency output circuit is arranged at the other end of the local oscillator intermediate-frequency duplex circuit and is used for outputting the intermediate-frequency signal to an external device. The band elimination filter adopting the symmetrically folded open-circuit branch structure has the advantages of simple structure, small size, easiness in tuning and the like. The terahertz mixer realized based on the band elimination filter has the excellent performances of wide band, low frequency conversion loss, high return loss and the like.

Description

technical field [0001] The invention relates to a subharmonic mixer, in particular to a terahertz miniaturized subharmonic mixer using symmetrically folded open-circuit stubs. Background technique [0002] Terahertz broadband high-sensitivity superheterodyne receivers are required for future high-speed wireless communications. The mixer, especially the subharmonic mixer, is the core device of the receiver, and its performance is directly related to the communication quality. Compared to cryogenic receiver systems, Schottky mixers offer outstanding qualities such as light weight, high reliability, low cost, and long lifetime. [0003] Low-pass filters, such as high and low impedance low-pass filters or CMRC low-pass filters, are often used in existing Schottky subharmonic mixer circuits. These low-pass filters need to have wideband, low insertion loss passband characteristics and wideband, high insertion loss stopband characteristics. The passband and stopband function to ...

AI Technical Summary

Problems solved by technology

However, this terahertz mixer with a low-pass filter still has the following disadvantages

First, the structure of these low-pass filters is relatively complex, and the number of microstrip line stubs is large

This will increase the difficulty and time of simulation tuning and optimization, which is not conducive to impedance adjustment and overall circuit performance optimization

Second, these low-pass filters are large in size and have a large aspect ratio

This will cause the thin-film circuit of the terahertz mixer, especially the most commonly used quartz thin-film circuit, to be broken more easily, which is not conducive to processing and assembly

Third, the return loss of each port of the currently reported terahertz mixer is poor, or little attention has been paid to it

This may cause port impedance mismatches to affect adjacent subsystems when the system is cascaded

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