Разработка и исследование субгармонического смесителя W-диапазона
Authors: Билинский К.В. , Кулешов Г.Е. , Александров А.В. 
Published: February 2025

В данной работе представлено устройство и принцип работы пассивного субгармонического смесителя W-диапазона (75–110 ГГц), нелинейным элементом которого является антипараллельная пара диодов с барьером Шоттки. Описана методика математического расчёта субгармонического смесителя. Приведены методика измерений потерь преобразования субгармонического смесителя на векторном анализаторе цепей и шумовой характеристики с помощью измерителя коэффициента шума. Представлены экспериментальные результаты спектров потерь преобразования и коэффициента шума субгармонического смесителя.

Introduction.Electromagnetic waves in the EHF (extremely high frequency) range are widely utilized in various industries and medicine. EHF transceiver devices offer several advantages over those operating in microwave, IR, VHF, and HF ranges. However, a significant drawback is the considerable attenuation of EHF radio waves when propagating in humid environments and challenging weather conditions. Subharmonic mixers have proven effective for converting EHF frequencies due to their desirable conversion and noise characteristics. This study aims to develop and create a W-band subharmonic mixer using domestic electronic components. To achieve this goal, we set the following tasks: 1) Conduct linear electromagnetic calculations and nonlinear analysis based on the equivalent parameters and a nonlinear model of Schottky barrier diodes (SBD); 2) Implement a subharmonic mixer and study its conversion and noise characteristics. Device and Principle of Operation.The developed passive subharmonic mixer features a waveguide-microstrip design that combines the fundamental harmonic of the EHF radio signal with the second harmonic of the local oscillator signal to produce an intermediate frequency. The frequency conversion occurs on an antiparallel pair of SBDs, fabricated on a GaAs substrate with beam leads. Mathematical modeling involves a step-by-step electromagnetic calculation of subharmonic mixer units using equivalent SBD parameters, followed by nonlinear analysis using the nonlinear SBD model. The conversion characteristics of the subharmonic mixer were measured with a vector network analyzer equipped with frequency extenders, while the noise characteristics were measured using a noise figure meter. Analysis of Results. For the implemented W-band subharmonic mixer, the conversion loss does not exceed 13 dB. In the 80–105 GHz range, the conversion loss is less than 11 dB, with an irregularity of ±0.8 dB. The optimal local oscillator power ranges from 8–12 dBm. The noise figure is no greater than 14 dBm. Qualitative and quantitative correlations between the mathematical calculation data and experimental results were observed, particularly in the spectrum of conversion losses and return losses at the radio signal input of the mixer. Conclusions. The developed W-band subharmonic mixer demonstrates characteristics comparable to existing analogues. A comparative analysis of the mathematical calculations and experimental results confirms the validity of the modeling methodology used. The resulting W-band subharmonic mixer is suitable for use in EHF transmitting and receiving devices and measuring equipment.