Passive millimeter wave ( PMMW) imaging system forms images by taking advantage of different radiation characteristic between targets and background. It has a great value of application in the fields of military reconnaissance, anti-terrorism, maintenance of stability, landing of aeroplane and so on. 无源毫米波探测技术利用目标与背景的辐射特性差异实现成像,在军事侦察、反恐维稳、飞机着陆等领域具有重大应用价值。