AD-band Circularly Polarized Magnetoelectric Dipole Array Using Rectangular Micro-Coaxial Line

A low-profile wideband circularly polarized (CP) magnetoelectric (ME) dipole array is proposed for sub-THz applications using micro-metal additive manufacturing (M-MAM). The antenna element consists of four planar patches with diagonal metal strips, L-shaped vertical walls, and a slotted cavity for improved gain and axial ratio (AR) bandwidth. A rectangular micro-coaxial line (RMCL) feeding cavity is designed for excitation. Furthermore, a 4×4 CP array with RMCL feed network is designed and fabricated, it achieves a measured operating bandwidth of 139–170 GHz (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\vert \boldsymbol{S}_{11}\vert$</tex> < -10 dB, AR < 3 dB) and a peak gain of 20.5 dBic. Simulations and measurements have good agreement.