Research For The3MM Preamplied Detection Receiver Circuit

Usually,millimeter-wave communication receiver has two forms:direct detection receivers and superheterodyne variable-frequency receivers. And the3mm preamplified detection circuit component belongs to direct detection receiver of millimeter wave components. In order to enhance sensitivity of receivers,low noise amplifiers are usually placed in front of detectors. In order to obtain a higher dectcted DC output voltage,video amplifiers are usually placed in the later stage of detectors,and operational amplifier usually serves as the followed video amplifiers. Compared with superheterodyne variable-frequency receivers,the outstanding advantage of direct detection receivers is that no local oscillator signal required,for which can greatly reduce the complexity of the system. Meanwhile direct detection receiver is a passive system,which is conducive to conceal itself in the battlefield because of its low power and low noise characteristics. And all these superiorities of the system make this type widely used in radiometers,low visibility imaging,radio astronomy,and other fields.The thesis is aiming for studying a front-end circuit component placed on the millimeter wave radiometer,which must be designed with high tangential sensitivity and ability to recovery high-speed pulse signal. The design has to integret low-noise amplifiers,detector,millimeter wave passive devices such as low-pass filter,lower frequency circuit such as voltage regulators and video amplifiers all together in a very limitied space with a size of60x40×15mm3. The preamplified detection circuit must work at3mm-band(Bandwidth8GHz)operating frequency and its tangential sensitivity shall reach-60dBm. Selecting high-speed operational amplifier will be required for adapting high-speed pulse signal.Firstly,half part of the thesis mainly for introducing the theoretical analysis of detectors and low-noise amplifiers,designing the preamplifier and the detector, comprehensively selecting the best project after comparing each of the schemes,and finally designing the3mm preamplified detection receiver circuit. As this project being presented more stringent requirements for size,MMIC products must be used to design the LNA part and a new type of diode should be used to form the3mm detector with important parameters such as voltage sensitivity and tangential sensitivity tested. Finally according to the requirement designing the3mm preamplify detection receiver circuit and carrying out the work of test.