A New Design of a Compact CSRR-Based Microstrip Low-Pass Filter for RF Harvesting Applications

This work presents the design of a microstrip low-pass filter based on Complementary Split Ring Resonator (CSRR) structure, optimized for association with a rectenna circuit. Efficient filtering is essential for Wireless Power Transfer (WPT) to suppress harmonics and maximize the RF-to-DC conversion efficiency. The proposed filter is mounted on an FR4 substrate ((ε r = 4.4), thickness = 1.6 mm) and optimized using the Moment Method (MoM) and the Finite Integration Technique (FIT).The overall dimensions of the structure are (37.18 mm × 11.3 mm), it ensures low insertion loss and strong harmonic suppression. The simulation results confirm good impedance matching and filtering performance, making this design suitable for rectenna systems that can be inserted into IoT, wireless sensors and remote sensing applications.