Terahertz mixer without local oscillator filter structure

Abstract

The invention discloses a terahertz frequency mixer without a local oscillator filter structure. The terahertz frequency mixer comprises an RF input waveguide, an LO input waveguide, a height reduction waveguide, a frequency mixing circuit substrate and a suspended microstrip probe section, and is characterized in that the suspended microstrip probe section is provided with an RF probe and an LO probe; and the terahertz frequency mixer is based on an integral circuit method. Adjustment of overall circuit matching, circuit energy is converted into intermediate frequency as much as possible so as to naturally complete isolation; the local oscillator filter is not needed for designing, the structure of the frequency mixer is greatly simplified, the overall size of the frequency mixer is reduced, and the length of the quartz substrate is shortened, so that the transmission loss is reduced, the bandwidth of the frequency mixer is widened, and the overall frequency mixing performance is improved; and the terahertz frequency mixer also has the advantages of simple structure, convenience in processing and easiness in implementation, and has a good application prospect.

Description

technical field [0001] The present invention relates to the technical field of terahertz mixers, in particular to a terahertz mixer without a local oscillator filter structure. Background technique [0002] Electromagnetic waves with a wavelength of 3mm to 30um are called terahertz waves. Their long-wave bands are close to millimeter waves, and their short-wave bands are close to infrared rays. They are in the intersection area of ​​electronics and photonics. Compared with microwaves in lower frequency bands, their characteristics are: 1. The spectrum range used is wide and the information capacity is large. 2. It is easy to realize narrow beam and high-gain antenna, so it has high resolution and good anti-interference. 3. Strong ability to penetrate plasma. 4. Large Doppler frequency shift, high speed measurement sensitivity. Terahertz waves are of great significance in communication, radar, guidance, remote sensing technology, radio astronomy and spectroscopy. The mixe...

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Problems solved by technology

[0003] In the terahertz frequency band, when the frequency is low, the size of the shielding cavity is relatively wide, and the length-to-width ratio of the quartz substrate will not be too high. When the frequency is high to a certain extent, in order to ensure single-mode transmission, the shielding cavity Generally, the design is narrow, while the IF filter, local oscillator filter and the matching structure between them are long, so the aspect ratio of the mixer designed by the traditional method and structure is generally too high

In the terahertz mixer, quartz is used as the substrate with low loss and good high-frequency performance, but the texture of quartz is very brittle and easy to break. If the aspect ratio is too high, the middle of the quartz will warp, making the circuit uneven and increasing the difficulty of assembly. After assembly, it is no longer a planar circuit, but an arc, which affects the performance of the mixer, increases the loss, and the size of the mixer is also large. On the other hand, the stability of the circuit is relatively poor.

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