| The rapid development of radar, communications and weapon guide systems brings exigent demand for microwave receiver's capability to detect any possible threaten in operation. Therefore, microwave receiver has become an important research area because of its applications in electronic war. Almost every microwave apparatus can be used in microwave receiver's design, except power apparatus. The advancement of microwave receiver's field could be thought as the product of device and logic circuit study, how to achieve receiver's miniaturization, integration and high precision is always its vital part. The demand for receiver's every guide line has become much stricter, especially for linearity requirement of receiver's radio frequency front-end. We assembled four modules on a Rogers5880 board, and realize the function of filtering, amplifying, mixing, and the last low-pass filtering output. The main work of the system can be divided into four main parts as the following:(1) 10.5GHz Bandpass FilterThe main contradiction of filter is caused by its function of dividing frequencies. In order to properly divide frequencies, not only need passband's attenuation to be as small as possible and stopbands'as big as possible, but also need a sharp and quick change between the attenuation of passband and stopband, thus to make their diversity obvious. We decide to use seven-sections Coupled-Line Filter after comparing the various filter circuits, and complete the quantitative analysis and optimization design by ADS, HFSS etc.(2) Three-stages FET Low Noise AmplifierAccording to the LNA's design theory and guide line, we decide to use NE3210S01 FET and choose the form of three-stages, thus we can achieve high stability, low noise and high gain. By using ADS and Ansoft Designer to run the computer aided design of amplifier's matching circuits, we can avoid the tiresome handmade calculation as well as quickening the work progress through its automatic optimization and tolerance analysis... |
PDF Full Text Request