Preliminary Experimental Studies on Quasi-Isotropic Circumferentially Short-circuited Dipole Antennas under Different Feed Schemes

A quasi-isotropic, circumferentially short-circuited magnetic dipole antenna is designed and different feed techniques are investigated. Coaxial cables without and with a sleeve choke have been respectively used to excite the antenna at 3.6 GHz. As can be seen, it has been experimentally validated that the sleeve choke is able to suppress the spurious radiation caused by the unbalanced sheath current, which enhances the radiation pattern’s uniformity in $zx$ - and $xy$-planes by 6.6 dB at most.