Adjustable low‐profile compact AIS antenna with reduced ground‐size sensitivity

Abstract

AbstractThis letter presents a novel reconfigurable low‐profile Automatic Identification System antenna that exhibits insensitivity to ground size. The antenna's physical dimensions measure 340 mm × 230 mm × 83 mm. Typically, smaller antennas require larger ground planes. However, changes in ground size cause the resonant frequency of the small antenna to shift, thereby limiting its working environment. Consequently, the antenna cannot function in systems with varying ground areas. To address this issue, a reconfigurable Inverted‐F antenna loaded with shorted parasitic elements is proposed. By switching the shorted state of a parasitic element, the antenna can operate within the required frequency band for different ground sizes. Simulated results demonstrate that the antenna can cover the 161–163 MHz frequency range when the ground size ranges from 250 × 250 to 450 × 450 mm2 with a shorted parasitic element. When the parasitic unit is not shorted, the antenna can cover the same frequency range when the ground size ranges from 450 × 450 mm2 to infinity. The proposed antenna achieves the characteristic of being insensitive to ground‐size changes in two states, and is widely applicable to devices with different ground sizes (such as ships and airplanes, etc.), reducing the cost of the system.