A Dual-band Circularly Polarized Stacked Microstrip Antenna for BeiDou Navigation Application

A single-feed dual-band circularly polarized (CP) stacked microstrip patch antenna is proposed for BeiDou system (BDS) application. The antenna is composed of a double-layer structure, and two layers are fed at the same time through a single feed probe to realize two operating frequency bands. The CP radiation is generated by loading a symmetrical L-shaped truncated corner and a fan-shaped notch in the bottom patch; triangle corners are introduced in the diagonal direction of the upper patch to generate CP radiation. Meanwhile, different slots are loaded on the upper patch and the bottom patch respectively to realize miniaturization. The antenna works in the 1.17645/1.57542 GHz band with a size of 4.6 mm × 80 mm × 80 mm $\left( {0.31{\lambda _0} \times 0.31{\lambda _0} \times 0.018{\lambda _0}} \right).{\text{ When }}|S11| < - 10dB$, the return loss bandwidth is 4.1% for the low-frequency band and 5.0% for the high-frequency band. The simulated 3-dB axial ratio bandwidths are 1.0% and 1.12%, respectively. The simulation results meet the BeiDou system requirements for microstrip antenna performance.