Wideband Compact Circularly Polarized SICL-Fed S-Dipole Array for Millimeter-Wave Applications

This letter presents a wideband circularly polarized (CP) antenna array for millimeter-wave (mm-Wave) frequencies, leveraging substrate integrated coaxial line for excitation. The CP element incorporates metallized vias, virtual ground patches, and inverted S-shaped strips. Subsequently, a 4 x 4 CP sequential rotation array is designed with a compact configuration that uses a single-layer printed circuit board (PCB) for the radiation layer and a multilayer PCB for the feeding layer. Fabricated prototypes exhibit an impedance bandwidth of 46.6 % [(25.17 to 40.45) GHz], a 3 dB axial ratio bandwidth exceeding 42.8 % [(25.9 to 40) GHz], and a maximum gain of 17.87 dBic. With its compact size, high gain, wide band, and low processing cost, the antenna array is suitable for beyond 5G and 6G mm-Wave communication systems.