A broadband terahertz even harmonic frequency mixing circuit and its working method

Abstract

The invention discloses a broadband terahertz even-order harmonic frequency mixing circuit and a working method, including a radio frequency input probe, an adjustable radio frequency matching branch, an antiparallel diode pair, a cascaded wide stopband high-suppression local oscillator filter, The local oscillator input probe, the intermediate frequency filter and the intermediate frequency output port are mixed and integrated on the microstrip line in turn; the anti-parallel diode pair is grounded; the radio frequency input probe is connected to the radio frequency input waveguide; the local The oscillator input probe is connected to the LO input waveguide. The terahertz tunable even-order harmonic mixing design method proposed by the present invention inherits the advantages of the traditional even-order harmonic mixer with small noise coefficient, improves the flexibility of circuit design and reduces the difficulty of circuit design, and It has the characteristics of broadband tunability, reduces the requirements for processing and assembly consistency, and has good manufacturability.

Description

technical field [0001] The invention relates to the technical field of mixers, in particular to a broadband terahertz even harmonic frequency mixing circuit and a working method. Background technique [0002] Terahertz wave is an electromagnetic wave with a frequency of 0.1THz-10THz. It has excellent characteristics such as perspective, broadband, transient, low energy, and coherence. Many such as object imaging, medical diagnosis, environmental monitoring, radio astronomy, and broadband mobile communication , satellite communications and military radar applications have been developed to this frequency band. No matter which field the terahertz wave is applied in, it is inseparable from the reception of the terahertz wave, and the performance index of the terahertz receiver largely determines the performance of the terahertz system. [0003] Since the even-order harmonic mixer has inherent advantages in design and implementation compared with the odd-order harmonic mixer, h...

AI Technical Summary

Problems solved by technology

At present, mixers in the terahertz frequency band are divided into two types: fundamental mixers and harmonic mixers. Fundamental mixers have a small noise figure, but have higher requirements for local oscillators; Reduce the requirements for local oscillators. The higher the harmonic order used, the lower the requirements for local oscillators, and the greater the noise figure. Considering the requirements of local oscillators and noise figures, receivers with high sensitivity in the terahertz frequency band generally The second and above-order harmonic mixing scheme is mainly used in the combination of suspenders and probes, and the method of grounding the end of the RF probe will completely change the electromagnetic field coupling mode of the probe and greatly reduce the probe. At the same time, due to the error of the grounding assembly during assembly, it will bring a large parasitic parameter and change the performance of the circuit. During processing, the grounding cavity needs to be finely processed, which increases the difficulty of processing.

The bandwidth of the local oscillator filter designed by the traditional method is generally insufficient, which will bring about the problem of insufficient harmonic suppression, increase the noise of the mixer, and reduce the mixing performance

In addition, the traditional design method still lacks a debugging unit, and once the circuit is assembled and finalized, it cannot be debugged and modified

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