Image frequency rejection frequency mixer structure for terahertz wave band

Abstract

The invention belongs to the technical field of terahertz devices, and provides an image frequency rejection frequency mixer structure for a terahertz wave band. The image frequency rejection frequency mixer structure includes an E-plane rectangular waveguide Chinese character 'tian'-shaped branch wire bridge 3dB directional coupler, micro-strip waveguide double probes, two frequency mixers, and a power combiner. A radio-frequency signal can generate two-channel radio-frequency signals with an equal amplitude and a 90-dgress phase difference via the E-plane rectangular waveguide Chinese character 'tian'-shaped branch wire bridge 3dB directional coupler, and the two-channel radio-frequency signals are input into two-channel frequency mixers respectively; a local oscillation signal can generate two-channel signals with an equal amplitude and a same phase via micro-strip waveguide double probes, and the two way signals are input into the two-channel frequency mixers respectively; two-channel frequency mixer intermediate frequency output signals are combined via the power combiner, and then are output; and each input end of the power combiner is provided with a 90-deree phase shifter for allowing the corresponding frequency mixer intermediate frequency output signal to generate a 90-degree phase shift, so that the two-channel frequency mixer intermediate frequency output signals are stacked in phase and output. The image frequency rejection frequency mixer structure is simple in structure and is applied to the terahertz wave band.

Description

technical field [0001] The invention belongs to the technical field of terahertz devices, and relates to an image frequency suppression mixer, in particular to an image frequency suppression mixer structure applicable to the terahertz band. Background technique [0002] THz waves refer to electromagnetic waves with a frequency in the range of 0.1-10THz (wavelength 0.03mm-3mm). Its long-wave band coincides with microwave and millimeter waves, and its short-wave band coincides with infrared rays. Its special position in the electromagnetic wave spectrum determines It combines some of the advantages of microwave and millimeter waves and light waves, that is, the advantages of stronger directionality of wave speed, higher resolution, and larger information capacity. Therefore, terahertz waves are widely used in many fields such as radar communication, object imaging, and environmental monitoring. [0003] In application systems such as terahertz communication, radar, and electr...

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Problems solved by technology

[0004] The suppression of the image frequency usually adopts the method of adding an image frequency suppression filter at the input end of the mixer. However, in the terahertz frequency band, the frequency of the radio frequency signal is much higher than the frequency of the intermediate frequency signal. If this method is used, the filter involved The center frequency is very high and the bandwidth is very narrow, which greatly increases the difficulty of filter design

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