A Compact Dual-Band Stacked Patch Antenna With Dual Circular Polarizations for BeiDou Navigation Satellite Systems

A compact dual-band and dual-circular polarization (CP) stacked patch antenna is investigated for BeiDou navigation satellite system. The proposed antenna employs a single coaxial probe to feed two layers of patches simultaneously, realizing dual-band operation. The bottom patch with symmetrical slant cornercuts and the top one with two rectangular stubs on the diagonal produce a pair of degenerated modes, achieving CP radiation. Furthermore, two L-shaped stubs are loaded on the top patch to widen impedance bandwidth. A prototype operating at the bands of 1.615/2.492 GHz was fabricated and measured. Both the left- and right-handed CP radiations are obtained concurrently in the dual bands. The proposed antenna has a profile of 4.6 mm (0.024λ
₀
) and occupies an area of 70 mm × 70 mm (0.38λ
₀
× 0.38λ
₀
). The measured impedance bandwidth with |S
₁₁
| <; -10 dB is 9.1% and 5.1% for the lower and upper bands, respectively. The measured 3 dB axial-ratio bandwidth is more than 1% for both bands.