RFID发射前端的零中频电路设计

软件无线电技术增强了射频识别（RFID）系统的信号处理能力及兼容性，而零中频的设计思想进一步简化了射频前端结构。然而射频前端依然发挥着不可替代之重要功能，若在设计中将其地位置于软件子系统之下往往会恶化整体性能。本文对基于零中频技术的RFID射频发射前端进行了必要的理论分析，在此基础上，按照性能指标要求对系统进行了预增益仿真和谐波平衡仿真，以此作为模块选型和优化的依据，最后完成了射频前端设计。仿真结果表明，各项指标较为理想。

The Design of Zero-IF Circuit used in the RF Front-End with RFID System

Software radio technology enhances signal processing ability and compatibility of RFID system, and zero-IF design can further simplify RF front-end structure. However, RF front-end still plays an important role and irreplaceable, the whole performance will be degraded if it is set lower than the software subsystem in the design process. This paper illustrates the essential theoretical analysis of the RF transmitter front-end based on zero-IF technique, in accordance with the system performance parameter, the system pre-gain and harmonic balance simulations have been taken to compare different modules and fulfill optimization. Thus, the RF front-end design is realized. The simulation results show that all the parameter meet the design requirements.