Jeanty, RobinRobinJeantySHIH-YUAN CHEN2023-10-262023-10-262023-01-012169-3536https://scholars.lib.ntu.edu.tw/handle/123456789/636623A bidirectional circularly polarized (CP) double asymmetric periodic leaky-wave antenna (PLWA) with wide 3-dB axial ratio (AR) bandwidth is presented. It is the first single-layer bidirectional CP PLWA with the same handedness in both half-spaces being reported. It consists of cascaded all-pass phase inverters hosted by a double-sided parallel stripline. A simplified unit cell facilitating theoretical analysis is first investigated, and both design rules and a radiation model for CP radiation are deduced. In particular, the phase quadrature and its weak dependence on the zenith angle, the origin of the same handedness in both half-spaces, are justified. Then, a practical unit cell design, suitable for PCB fabrication, is proposed, and a 30-cell PLWA prototype for the sub-6-GHz band is designed and fabricated, which exhibits a 10-dB return loss bandwidth from 4.5 to 7.0 GHz. Although the transitions feeding the antenna and the fabrication imperfections perturb the radiation, mainly in the upper half-space, the prototype matches the simulations from 4.6 to 6.9 GHz, corresponding to scanning from +45° to -34° in the lower half-space. The measured realized gain ranges from 4.4 to 6.6 dBic in the operating band. Meanwhile, the axial ratio of the scanning beam remains below 3 dB throughout the 40% bandwidth.Circular polarization | double-sided parallel striplines | Impedance | Inverters | Lattices | Leaky wave antennas | leaky-wave antenna | phase inverters | Prototypes | Slot antennas | Substrates | the same handedness[SDGs]SDG7journal article10.1109/ACCESS.2023.33209522-s2.0-85172984493https://api.elsevier.com/content/abstract/scopus_id/85172984493