Multi-beam Antenna Of The Passive Millimeter Wave Scan Imaging Studies

Millimeter wave(MMW) is between optical wave and centimeter wave, which not only has optical detector's precision, but also has all-weather working characteristics of microwave. Compared with the microwave, MMW devices are smaller and lighter, so it is particularly suitable for missile-borne weapons. MMW is close to optical band, so it mostly transports at straight line and has small diffraction.MMW beam is narrow. It is high precision guidance device. PMMW has the ability of anti-interference and anti-stealth. In missile's guidance device, MMW device instead of the microwave is the trend.MMW imaging guidance technology is the developing trend of MMW guidance technology. It is developing from one-dimension imaging to tow-dimension imaging and 3D imaging. Imaging method are scanning imaging and focal plane staring imaging. Advantage of focal staring array imaging is that it uses electric sweeping which can instantaneously observe the target. It removes the set of scanning and imaging rotating mirrors and devices. It has higher target detect ability and spatial resolution and SNR. And it has lower false alarm rate and weight and size. Line scanning imaging is more easy and lower cost, so it is the mostly developing trend of array imaging.In this dissertation, according to key technologies of missile MMW focal plane imaging, following issues are studied:At first, MMW imaging theories and methods are studied, and the focal plane imaging theories are studied. This paper summarized the main objects'MMW brightness temperature, and introduced the development course of MMW detection and orientation.At second, the mostly using antennas are studied. Mainly analyzing the using of dielectric lens antenna and cassegrain antenna in MMW detection system. Geometrical optics method is used to analyze dielectric lens antenna and cassegrain antennas'design.Thirdly, the currently most using millimeter wave radiometers are described. Working theory of MMW radiometer is studied. Relationship between radiometers'parameters and target detecting is analyzed. Under a simulation platform, the hight-frequence parts of the system and detection circuit had been simulated.At last, emulation method and characteristics of the output antenna temperature signals are studied when 3mm PMMW radiometer detects the targets. Under the single and multi-beam scanning situation, space targets'output antenna temperature signals of millimeter-wave are simulated. Simulation of the MMW imaging is studied, and the relationship of radiometer sampling rate and spatial resolution on image quality are discussed.