A Compact and High-Efficiency Antenna Design for Tire Pressure Monitoring System Applications

This article proposes a novel design for a compact antenna that exhibits high efficiency and low interference and is suitable for tire pressure monitoring systems (TPMSs) based on Bluetooth communication interface at 2.4 GHz. Tires constitute a dissipative environment, where the efficiency of the TPMS is affected by both antenna losses and losses from the tire parts, both conductive and dielectric. This article conducts an analysis and simulation of the electromagnetic (EM) environment of the tire and identifies the optimal polarization and placement position for the TPMS antenna to minimize resonance losses of EM waves within the tire, enhance lateral radiation, and thereby improve the overall efficiency of the TPMS. The requirements for the TPMS antenna, including pure linear polarization, low common mode currents, compact size, wide bandwidth, high efficiency, and static mechanical protection, are derived from the requirements of the TPMS application and the EM environment within the tire. The proposed antenna satisfies all of these requirements and is based on a wideband, high-efficiency EM structure. The final antenna design achieves a bandwidth of 35% (2.24-3.22 GHz), a gain of 2.1-2.4 dBi, and a cross-polarization level ranging from -29 to -16 dB. These results demonstrate that the antenna is a strong candidate for being employed in TPMS applications.