# Scaled Modeling and Measurement for Studying Radio Wave Propagation in Tunnels  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [EMAIL_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [PERSON]_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [EMAIL_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [PERSON]_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [PERSON]_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [PERSON]_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [PERSON]_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [PERSON]_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [PERSON]_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [PERSON]_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
1 Department of Electrical and Electronics Engineering, Ariel University, Ariel 40700, Israel;  
[EMAIL_ADDRESS] (N.B. ); [EMAIL_ADDRESS] (E.L.); [EMAIL_ADDRESS] (Y.R. ); [EMAIL_ADDRESS] (M.G. ); [EMAIL_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (Y.P)  
[PERSON]  
2 Department of Chemical Engineering and Biotechnology, Ariel University, Ariel 40700, Israel;  
2 [EMAIL_ADDRESS] (Correspondence: [EMAIL_ADDRESS] 2021, 10, 53. [[https://doi.org/10.3390/electronics10010053](https://doi.org/10.3390/electronics10010053)]([https://doi.org/10.3390/electronics10010053](https://doi.org/10.3390/electronics10010053)) 22 December 20202  
scale models of tunnels in a lab environment to perform experiments that imitate real-world conditions [5; 6]. Other works relied on results in the existing literature to confirm the models they developed [7]. Another approach involves using channel models for simulations, such as the waveguide model [8; 9], two-slope model [10], ray tracing [11; 12; 13], and numerical solutions to Maxwell's equations [14; 15; 16; 17; 18]. These models are suitable for empty tunnels with straight walls, making the propagation environment relatively simple and allowing it to be approximated to a waveguide. The reported experiments were performed on various tunnels, and all but a few [4] were performed for large tunnels rather than pedestrian tunnels. The main differences between pedestrian and transport tunnels and mines are the dimensions and cross-sections, parameters that significantly impact the wave propagation [19; 20] and electromagnetic properties [21]. Car and train tunnels are usually wide with low ceilings while pedestrian tunnels are narrow and have high ceilings. These differences affect the frequency and polarization of the transmitted waves. The majority of the theoretical and experimental research in predicting wave propagation concerns long distances and does not consider the transmitter's close vicinity. This paper is aimed at investigating the propagation of RF waves in relatively 'narrow' tunnels such as pedestrian walkways and corridors. The scenario becomes interesting for wireless communication links operating at Ultra High Frequency (UHF) or Super High Frequency (SHF), when the dimensions of the tunnel are not much larger than the wavelength. In addition, the paper demonstrates the use of scaled models for experimental radio wave propagation studies. In this paper we report on the results of a field experiment performed in a pedestrian tunnel with a relatively small cross-section: a height of 1.85 m and width of 1 m. Measurements and simulations were performed for frequencies of 1, 2.4, and 10 GHz.