On-glass diversity tire pressure monitoring and FM antenna systems

Tire pressure monitor systems (TPMS) in the automotive industry have proven to be an essential component, not only for safety aspects, but also for fuel efficiency and tire life. While some tire pressure sensors can also provide outputs of temperature and sensor battery life to the receiver, the RF signal transfer of such information becomes quite complex in real-life applications. Most TPMS receiving antennas are utilized as a remote keyless entry (RKE) antenna as well. The dual purpose of one antenna element often yields performance degradation in either one or both systems. This issue becomes more prominent in larger vehicles and trucks. A diversity TPM receiving antenna system based on signal strength is described. Two distinct antennas, located on the side windows of the vehicle are utilized in a diversity setting. Typically, the signal from the sensor most distant from the receiving antenna degrades most and becomes problematic for further processing. The proposed scheme overcomes poor signal reception in such cases and can be implemented in a cost-effective way if combined in an FM diversity system.