Omnidirectional Compact Microstrip Antenna in 2.45 GHz band for Ocean Wireless Sensor Network

Study on marine environment and marine ecosystemic maintenance and study to enable the sustained production of living marine resources have proceeded at authors’ university [1]. As part of these studies, remote monitoring for growth and feed consumption of the fish, and temperature and salinity of the seawater in the offshore fish-tank is required. To achieve the remote monitoring on the ocean, the antenna incorporated inside the buoy (the antenna for Smart buoy) is needed for wireless sensor network in the 2.45 GHz band. It is required that the height and width of the antenna for smart buoy are as small as possible. The omnidirectional pattern with the maximum radiation in the low elevation angle is suitable for ocean wireless sensor network. In [2] [3], the low profile planar antennas with omnidirectional radiation pattern have been proposed for 2.45 GHz band-application. The sizes of these antennas are small. However, the impedance bandwidths are narrow and the gains are small.