A compact six port antenna for better spectrum utilization efficiency in cognitive radio applications

Abstract

In this article, a novel six port antenna for better spectrum utilization efficiency in cognitive radio (CR) applications is presented. In this six port antenna system, an ultra‐wideband (UWB) sensing antenna and five wideband/narrowband (NB) antennas are integrated on the same substrate in a compact area of 1134 mm2. Antenna associated with port 1, which is meant for sensing, has −10 dB reflection coefficient bandwidth of 3 to 11 GHz and the antennas associated with ports 2, 3, 4, 5, and 6 have −10 dB reflection coefficient bandwidths of 3.6 to 5.8 GHz (single band), 2.9 to 3.6 GHz and 5.4 to 7.98 GHz (dual band), 7.95 to 8.38 GHz and 9 to 9.85 GHz (dual band), 8.38 to 9 GHz (single band) and 9.7 to 10.7 GHz (single band), respectively. Minimum isolation of 20 dB is attained between UWB sensing antenna and any narrowband/wideband antenna except between the antennas associated with ports 1 and 2 where minimum isolation of 12 dB is achieved over the operating bandwidth of UWB sensing antenna. Moreover, among all wideband/narrowband antennas, isolation of less than 15 dB is achieved. More importantly, the narrowband and wideband antennas meant for communication cover all frequency bands in UWB and a good match between the simulated and measured results is noticed.

A reconfigurable integrated 4‐port UWB and NB antenna system for cognitive radio application

“…Proper switching mechanism is employed to select a suitable NB antenna for communication. In References27–31, authors discussed numerous multi‐port integrated ultra‐wideband and NB antenna structures for cognitive radio applications. One particular NB antenna is excited with required communication signal (termed as excitation switching) depending on the identified spectrum hole frequency by the UWB sensing antenna.…”

“…If multiple spectrum holes are identified, then particular operating NB antennas are excited with communication signals and remaining NB antennas are kept idle. In the literature, [27][28][29][30][31] several multi-port integrated UWB and NB antenna structures are explored for cognitive radio application. However, reconfiguration mechanism is not adopted in this literature.…”