Study of Electromagnetic Field Attenuation with Distance Using Friis-Based Modeling

Manas Singhal, Shuchita Saxena — Tue, 06 Oct 2026 00:00:00 +0000

The propagation of electromagnetic waves from transmitting antennas plays a crucial role in wireless communication systems. This study investigates the variation of radiated electric field strength with distance using theoretical modeling and computational simulation. The analysis is based on the Friis transmission equation, which establishes an inverse relationship between field strength and distance from the transmitting antenna. A SciLab-based simulation is employed to compute and visualize the electric field variation over a wide range of distances. The results demonstrate that as the distance increases, the field strength decreases significantly, confirming theoretical expectations. This behavior is essential for understanding signal attenuation in practical communication systems, including mobile networks and satellite communication. The study provides insight into electromagnetic wave propagation characteristics and highlights the importance of antenna parameters in determining signal strength. The findings can be useful for optimizing wireless system design and improving transmission efficiency. The simulation confirms that the received field strength decreases as the distance from the transmitting antenna increases, in agreement with theoretical expectations.

24 GHz FMCW-Based Radar Occupancy Detector with Embedded Firmware and Configurable GUI

Fri, 30 Oct 2026 00:00:00 +0000

Common presence sensors such as Passive Infrared (PIR) sensors and ultrasonic modules exhibit critical performance gaps when tasked with detecting stationary occupants, operating in thermally variable environments, or providing user-configurable detection parameters. This paper reports the architecture, firmware design, and experimental validation of a small-form-factor presence detector built around a 24 GHz Frequency-Modulated Continuous Wave (FMCW) radar, aimed at overcoming these limitations. The system integrates the LD2420 single-chip radar module with an ATmega32U4 microcontroller deployed on the RFME P567858 custom printed circuit board, communicating via UART at 256,000 bps. An ATmega32U4-to-PC USB CDC bridge at 115,200 bps enables real-time data streaming to a feature-rich Windows desktop GUI developed in C# (Microsoft Visual Studio). Zone-based detection logic partitions the sensing field into three spatial regions: Zone A (0–50 cm, Critical Alert), Zone B (50–200 cm, Near Presence), and Zone C (200–500 cm, Far Presence). Angular scanning coverage is extended through a NEMA 17 stepper motor driven by an A4988 microstepping driver at 1/16 resolution, achieving 0.1125° per step. Experimental results demonstrate reliable human presence detection from 50 to 500 cm with a maximum absolute error of 3.7 at 350 cm, 100% zone classification accuracy across 300 test frames, and an end-to-end GUI update latency of 64 ms ± 12 ms. The proposed platform represents a cost-effective, configurable, and privacy-preserving alternative to existing occupancy sensing solutions.

Journal of RF and Microwave Communication Technologies

Study of Electromagnetic Field Attenuation with Distance Using Friis-Based Modeling

24 GHz FMCW-Based Radar Occupancy Detector with Embedded Firmware and Configurable GUI