毫米波与普通微波几乎具有同样悠久的历史,但其应用却远不如微波那样广泛。限制它发展的主要原因是大气传输损耗较大,而功率源等关键器件发展又很缓慢。至今,除几种35千兆赫雷达已投入应用外,毫米波雷达仍处于样机研制和系统试验阶段。但是,最近几年毫米波技术有了重大突破,已迅速地进入了比较成熟的阶段。目前,频率低于140千兆赫的毫米波系统,其所需器件已经完备,且已达生产水平。另一方面,微波、红外、激光和光-电等军事系统,在发展中遇到了一些严重障碍,迫切需要利用毫米波技术的潛在优点。这样,毫米波技术就又应运而起,成为最活跃的技术领域之一。现在,毫米波技术已进入系统应用和向更高频段发展的阶段,可望不久将出现频 Millimeter waves and microwaves have almost the same long history, but their applications are far less extensive than microwaves. The main reason that limits its development is the large transmission loss of the atmosphere, and the development of key components such as the power source is very slow. To date, millimeter-wave radars are still in prototype development and system testing with the exception of several 35 GHz radios. However, in recent years, millimeter wave technology has made a major breakthrough and has rapidly entered a relatively mature stage. Currently, millimeter-wave systems with frequencies below 140 gigahertz are fully equipped and up to production levels. On the other hand, military systems such as microwave, infrared, laser and optical-electricity have encountered some serious obstacles in development and there is an urgent need to take advantage of the potential advantages of millimeter-wave technology. In this way, millimeter-wave technology has come into being and becomes one of the most active technological fields. Millimeter-wave technology has now entered the stage of system application and development to higher frequencies and is expected to appear soon