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In this letter, a multibeam leaky-wave antenna (LWA) based on a modified Luneburg lens (LL) beamforming network is proposed. The antenna performs a simple structure and low profile with 2-D beam scanning. First, the modified LL serves as a beamforming network since its variation range ratio of refractive index can be determined by the relative permittivity of the substrate. This can be simply achieved using a printed circuit board technique rather than the square root of two of conventional LL. Then, the relationship between the input port angle and the multibeam angle is analyzed using the geometric-optical method. Finally, a high-scanning-rate LWA array based on spoof surface plasmon polaritons is designed, and its open-stopband is effectively suppressed. A prototype is simulated and fabricated. The measured results show that the proposed antenna has a multibeam range of −42° to 40° in the E-plane and a beam scanning range of −53° to 44° in the H-plane within 8–10.5 GHz, which agrees well with the calculation and simulation.

In this letter, a dual circularly polarized periodic leaky-wave antenna based on spoof surface plasmon polaritons (SSPPs) with linearly sweeping beams is proposed. The antenna can simultaneously radiate left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) beams. Single-arm Archimedean spirals serve as radiators and are designed. Based on linearity analysis and curve fitting, SSPPs structure with potentially linear scanning ability are selected. Finally, the axial ratio (AR) and S-parameter for the proposed SSPPs antenna with spiral radiators are optimized around the broadside frequency using longitudinally asymmetric analysis. A prototype is fabricated and measured results show that the proposed antenna achieves a relative 3 dB AR bandwidth of 31.6% (8–11 GHz) with the same LHCP and RHCP scanning range of 65° and linearly sweeping ability.