The RF Research Of The Electronic Toll Collection System

Nowadays, the lives of ordinary people are combined more and more with RFID (Radio Frequency Identification) technologies. RFID technologies are more convenient than the traditional contacted-card technologies due to the use of radio frequency to transfer information.Electronic Toll Collection (ETC) is one of the most important applications of the RFID technologies. The ETC system has three important parts:The Road-Side-Unit, The On-Bus-Unit, and the computer systems behind them. The 5.8GHz band is exclusive to the ETC system by the Dedicated Short-Range Communication. And the ETC system has already been used in the main highways of our country.This paper first introduces the RFID technology and its applications, and then, introduces the ETC technology and its applications, while at the same time with the analysis of the Dedicated Short-Range Communication.The paper analyses the general features of microwave receiver circuits before the design of the RSU system, and then gives a microwave receiving circuit based on the requirements of RSU, which includes:a band-pass filter at 5.8GHz, the theoretical analysis and choose of LNA (low noise amplifier) and Mixer chips, the design of a band-pass filter at 40MHz, a ASK (Amplitude Shift Keying) demodulate circuit.