Analysis of Welding Pad for Terahertz Hybrid Integrated Mixer

In this paper, the influence of the silver glue on circuit performance and the reasons for its formation are analyzed in a terahertz hybrid integrated mixer. A validation analysis was carried out in the 600 - 700 GHz band with the aid of simulation software. Then a terahertz hybrid integrated mixing circuit with large pads was proposed in order to reduce the influence of the silver glue. Through the comparison of simulation results, it can be seen that after using large pads, the silver glue used for connection mainly concentrated on pads, which cannot have a significant impact on the matching of the circuits. The use of large pads also to a certain extent eliminates the resonance effect caused by silver glue. A terahertz hybrid integrated mixer with large pads was processed, assembled and tested. The test results show that the conversion loss is less than 14 dB under an RF frequency of 600 - 667 GHz. The experiments prove good consistency between measured and predicted conversion loss of the mixer using large pads. The difference between the measured and predicted conversion loss is only within 1.8 dB.