The Design Of A 0.34THz Even Harmonic Mixer

Recently, terahertz wave has been a hotspot of scholars, because of its unique advantages in many areas. As the increasing of the frequency about the imaging or communication systems, there’s an in-depth study for the receiving and generating of THz wave. The mixer is the essential component of the THz receiver, so it’s important for the performance of the whole receiver. Among the existing terahertz frequency conversion systems, the Schottky mixer is widely used in terahertz frequency transformation circuits, because it works at room temperature, with no other harsh working conditions.In this paper, the mixers work at 0.34 THz, which is an atmospheric window. At first, the paper researched the even harmonic mixer technology. And then it used antiparallel diode pair to reduce odd harmonic mixing energy. At last, it used 8th and 16 th harmonic mixer circuit to make the LO frequency to be 1/8 or 1/16 of the RF frequency, which reduced the requirements. According to a series of classical theory and data, the paper created the 3D physical model in HFSS and SPICE model in ADS, and researched the Co-simulation with the two software. Compared with the other traditional model, the paper increased two new cathode ports in the model to deal with the differences between the model in software and the real object. After researched the precise model of the diode, this paper designed the other parts, including waveguide-suspension microstrip line transition and RF-stop CMRC filter and match circuit with 50 um quartz substrate suspension microstrip lines, waveguide-microstrip line transition and DGS filter and CMRC filter with 0.127 mm Roggers 5880, etc.After simulated and processed the circuit, the paper measured both of the two 0.34 THz mixers. The 8th harmonic mixer’s best conversion loss is 24.5dB, and its conversion loss is better than 36 dB between 261 GHz and 373 GHz. The 16 th harmonic mixer’s best conversion loss is 30.6dB, while the conversion loss is lower than 46 dB from 261 GHz to 377 GHz.The experimental results provide reference and experience for the research of terahertz even harmonic mixer circuit, the achievement contribute to the development of terahertz semiconductor device and terahertz spectral analysis in our country.