Recent Advancements in Quasi-Isotropic Antennas: A Review

A Compact, Low-Profile, Broadband Quasi-Isotropic Antenna for Non-Line-of-Sight Communications

“…In this study, the performance of the quasi-isotropic antenna is measured by the gain deviation. The previously reported broadband quasi-isotropic antenna showed a maximal gain deviation in the range of 6 to 12.7 dB [28], and we set 10 dB as the gain deviation criterion. In quasi-isotropic antenna designs, the minimal gain value is also important, as is the gain deviation.…”

“…In this paper, we propose an electrically small, low-profile, and highly efficient q isotropic antenna that is matched over broad frequencies from 1.8 to 4.3 GHz, or 81 To provide reliable and robust NLOS communications with less cumbersome wireless connections and battery-less sensors, it is desired for the antenna to operate in broad frequencies and radiate electromagnetic energy uniformly in all directions. Such uniform radiation characteristics could be obtained by an ideal isotropic source [13]; however, due to its non-existence nature [14], researchers instead showed a way to obtain a nearly uniform radiation pattern in the name of quasi-isotropic antennas [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. These types of antennas can be achieved using radiation pattern synthesis, such as by a combination of electric and magnetic dipoles, a different orientation of dipoles, two electric dipoles with a 90 • phase shift, etc.…”

Research on Quasi-isotropic Radiation of Small Circular Arc Antenna

“…However, isotropic antennas are impossible in theory, because the transverse electric field in the far field region cannot be uniform over a sphere if the field is linearly polarized everywhere [2], [3]. So quasi-isotropic antennas were proposed and commonly used in applications such as radio frequency identification, radio frequency energy harvesting, and wireless access points [4].…”