Towards Monitoring and Identification of Red Palm Weevil Gender Using Microwave CSRR-Loaded TL Sensors

Abstract

This paper presents for the first time the design of a microwave sensing setup for the potential monitoring and identification of red palm weevil (RPW) gender type. The microwave sensor consists of a planar two-port transmission line (TL) with a single complementary split-ring resonant (CSRR) inclusion etched from the bottom metallic layer. The CSRR sensor is placed on top of a customized non-conductive container. The microwave sensing setup was designed, numerically demonstrated, fabricated and tested experimentally. Simulated results correlate quite well with the experimental data. Moreover, the sensitivity of the CSRR sensor when in close proximity to different RPW genders was evaluated both numerically and experimentally. Based on the measured results from 15 RPW samples with different body sizes, different RPW gender types showed unique microwave signatures. A notable shift in the sensor’s resonance frequency was achieved, where on average a resonant frequency shift of 10% for adult RPWs was achieved, while a 2.4% frequency change was obtained for larvae (young) RPWs. Hence, the proposed microwave sensing setup can be adopted in field trials to examine and differentiate between various RPW genders at various developmental stages.

New Complementary Resonator for Permittivity- and Thickness-Based Dielectric Characterization

“…The MTL of the width a 1 = 2.192 mm is printed on the upper layer of the AD250C substrate of a square shape and size b 1 = 20 mm and b 2 = 20 mm, as shown in Figure 1a. The geometry of the CCAR is derived from the fundamental structure known as the complementary square split ring resonator (CSSRR), which has been used recently to design negative group delay circuit [18], substrate-integrated waveguide filter [19], wideband antenna [20], and microwave sensor [21]. Figure 2 shows the progression of the CCAR geometry from its predecessor, the CSSRR.…”

“…Initially, a CSSRR with the three geometric parameters (d 1 = 4 mm, d 2 = 3 mm and d 3 = 0.5 mm) is designed, as shown in Figure 2a. The initial geometric parameters were chosen by a comprehensive analysis of the existing literature [18][19][20][21]. After simulation, the CSSRR under investigation exhibits a resonant frequency of 8.6 GHz, accompanied by a notable notch depth of −26.7 dB.…”