Design and Verification of an Electrically Small, Extremely Thin Dual-Band Quasi-Isotropic Antenna

A novel design of an electrically small, dual-band quasi-isotropic antenna with a microstrip balun is presented in this letter. A quasi-isotropic radiation pattern is realized from the total current flow over the proposed structure at two different frequency bands. The electrical size ka of the antenna is 0.49 with an extremely thin profile of 0.0014λ
_g
. The antenna measurements reveal good uniformity of the radiation pattern with a maximum gain deviation of 5.83 dB at 942 MHz and 8.24 dB at 1.71 GHz with 57% and 95% radiation efficiency, respectively. The radiation performance of the antenna is also verified through wireless power receiving experiments in an office non-line-of-sight (NLOS) environment.