MMIC毫米波焦平面阵列接收机关键技术研究

下一代W波段焦平面阵列接收机的规模已经达到100像元，配置后将成比例提升望远镜观测效率，兼顾大口径天线的高灵敏度和大视场，加速数据获取并促进科学产出。以MMIC放大器为核心的有源集成化阵列单元在灵敏度方面已经接近传统SIS超导混频器方案，并且有潜力突破百像元阵列的冷量限制和本振分配限制，相关技术也是国际天文机构研究的热点和难点。本项目针对MMIC毫米波焦平面阵列接收机的关键技术开展研究，并试制2件阵列单元样机，主要指标和特点：1）频率覆盖W波段全带宽70-116GHz，双线极化；2）采用有源OMT技术，减少法兰、改善驻波并缩小外形尺寸，接收机噪声温度优于60K；3）实现馈源和有源OMT在内的阵列单元一体化设计，径向尺寸小于31mm，改善外沿像元方向图和效率，满足即插即用的阵列式集成方式；4）开展基于10K制冷机的100像元阵列冷量分析和杜瓦设计。

The next generation of W-band Focal Plane Array (WFPA) receivers has reached the scale of 100 pixels, and scales up the observation efficiency of radio telescopes. The WFPA is compatible with high sensitivity and large field of view (FOV) of large-aperture telescopes simultaneously, that will accelerate the acquisition of observation data and promote radio astronomy sciences. The sensitivity of the active array unit with MMIC cryogenic low noise amplifiers integrated is very close to the traditional SIS receiver structure, and also has the potential to break through the technical limits of cold power provide by 4K cold head and Local Oscillator distribution in the case of the array with hundreds of pixels. In this proposal, the key technologies of MMIC Millimeter-wave FPA receiver will be studied, and two prototypes of array unit will be built. The main features and characteristics includes: 1) 70-116 GHz frequency coverage which called full bandwidth of W-band, and dual linear polarizations per pixel. 2) The Active OMT technology will cancel the UG387 flanges between OMT and LNAs which will improve the standing wave and reduce the overall size. The lower than 60K receiver noise temperature is expected; 3) A array unit including feed horn and Active OMT integrated with LNAs, will be fabricated and assembled to one piece. The radial size of whole unit is less than 31mm, which will improve the radiation pattern and aperture efficiency of the edge pixels. The plug-and-play integration mode will be adopted; 4) A cryostat of the WFPA with 100 pixels will be designed, and cooling capacity analysis based on 10K refrigerator will be carried out.