Active antennas in focus: a systematic review of technologies, performance, and limitations in comparison to passive antennas

Integrating active devices in antenna systems highly improves its functionality over the traditional antenna systems that are passive in nature and therefore this aspect is of great focus to modern communication technologies. A systematic review compared both passive and active antenna strategies, noting that the possible gain benefits of active systems could be achieved. An analysis was conducted on both active and passive antennas at frequencies of 1, 3, 5, 7, and 10 GHz to elucidate the impact of active components on antenna efficacy, while a ±0.5 dB uncertainty margin was introduced to reflect typical amplifier tolerance. The results showed a figure of 6 dB gain at 10 GHz compared to the 2 dB reported by the passive antenna at the same frequency. Further analysis at 2.4 GHz indicated that the active antenna showed an increase in the radiation of 20 dBi over its passive alternative, and thus the effective use of active antennas was confirmed, leading to major applications of wireless communication.