Dual-band dual-beam millimeter-wave antenna using dual circular microstrip rings

Abstract The growing demand for high-capacity millimeter-wave (mmWave) communication systems requires compact, high-gain antennas that provide efficient spatial coverage while remaining simple to fabricate and integrate. This article presents a novel dual-band, dual-beam microstrip antenna based on a dual circular-ring radiator. Unlike existing designs, the proposed antenna achieves wide dual-band, dual-beam operation without vias, parasitic elements, or metamaterial loading, resulting in a compact, low-profile architecture that is straightforward to fabricate using standard printed circuit board (PCB) technology. Excitation of higher-order resonant modes, combined with optimization of the ring geometry and ground plane, produces symmetric dual-beam radiation in the quasi-E plane across two wide operating bands of 24.2–30 GHz and 32.5–43.5 GHz. Measured results agree closely with simulations, validating the antenna’s wide impedance bandwidth and stable radiation characteristics. The antenna generates dual beams at ± 40 $$^{\circ }$$ in the lower band and ± 24 $$^{\circ }$$ in the upper band, achieves a peak realized gain of 9 dBi at 38 GHz, and maintains gains exceeding 6 dBi across both bands. These characteristics make the proposed antenna a practical and cost-effective solution for next-generation indoor mmWave communication systems.