A High-Efficiency, Indirectly-Fed, Dual Moon-Shaped Printed Antenna for Measuring Sand Gradation

In this paper, an enhanced bandwidth antenna featuring a dual moon-shaped patch design is presented. The antenna occupies an area of 153 mm by 130 mm and operates within the frequency band of 0.69 to 1.19 GHz. The structure is printed on an FR4 substrate with a dielectric constant of 4.3 and a substrate thickness of 1.5 mm. It achieves a bandwidth of 0.5 GHz (50%) and a minimum return loss of -47 dB at the resonant frequency of 1.00 GHz, with a gain of 4.02 dB. The proposed antenna consists of a dual moon-shaped patch positioned on the top of the dielectric substrate. It utilizes an indirect feeding method via a transmission line with two arms to enhance bandwidth. The ground plane is partially reduced, which allows the antenna to resonate at a lower frequency. Additionally, a triangular slot on the backside improves impedance matching from -15dB to -47dB, thus optimizing the electric size. Experimental results confirm the antenna's performance, showing excellent agreement with the predicted parameters. The antenna demonstrates robust performance with effective gain and high bandwidth, making it suitable for practical applications in infrastructure monitoring. An innovative method for measuring sand gradation on-site is being developed by voltage network analyzer Device, eliminating the need for traditional sieve analysis in the laboratory.