Research On Silicon-based L Band Down Converter

L band is one of the main frequency band used in modern mobile system. The L-band receiver is widely used in the field of military and civil communication. Especially in recent years, the development of mobile communication field is very rapid, the demand for products is also very large. Therefore, the research of L band equipment has far-reaching social significance and great economic value. With the development of mobile communication, the performance requirements of mobile devices are also increasing. In general, the heterodyne receiver is widely used in the practical application because of its good reception performance. This has also attracted a large number of academic researchers and designers to carry out a more in-depth study of it. One of the research focuses on the suppression of image frequency, The key component to achieve this function is the mirror frequency suppression mixer, its performance on the overall performance of the receiver is very large.This paper mainly studies the mixer based on CMOS technology. First simply introduced development of CMOS mixers, expounds the development process and the development direction in the future. Then the structures of image-rejection are compared. The technical specifications of the commonly used Gilbert mixer are analyzed, and some improved structures are analyzed. On the basis of this, a kind of DC source which can realize the 5V-3.3V conversion and the output current capability of more than 100 m A is designed. At the same time, we have made some changes to the traditional Gilbert mixer, and designed a mixer unit that use single port input and do not use the bridge.According to the requirements of the project, an image-rejection mixer is designed, which is highly linear and does not use the inductor. The mixer mainly consists of mixing unit, the local oscillator, output buffer amplifier and DC power supply. The simulation using Cadence IC 5141 software, and extracted with Calibre. The pre simulation and the post simulation results meet the design requirements. The mixer which is designed using TSMC 0.35 ?m Si Ge 3p4 m technology library was designed and fabricated.