A Filtenna-Lens Complex for Generation of Circular-Polarized Filtering Bessel Beam

In this work, a filtenna-lens complex is proposed for the generation of circular-polarized (CP) filtering Bessel beam at 60 GHz millimeter-wave (mmW) frequencies. The filtenna produces a CP filtering spherical wave, which impinges on the lens. The lens then transforms these waves into a non-diffractive Bessel beam, thereby achieving the desired CP filtering Bessel beam. Experimental results demonstrate that the measured −10 dB impedance bandwidth spans from 56.7 to 63 GHz, with the axial ratio remaining below 3 dB, ensuring high-quality circular polarization. Additionally, the non-diffractive beam is maintained over a propagation distance exceeding 300 mm. These findings confirm the effectiveness of the proposed method.