## 2 Materials and Methods
### Measurements in Near-Field and Far-Field Areas  
A theoretical calculation was carried out: the field distribution can be calculated using the parameter Lz = 2D\({}^{2}\)/\(\lambda\), where D is the dimensions of the antenna's active (radiating) part, \(\lambda\) is the wavelength, and Lz denotes the transitional field range. According to the calculation, we chose a sufficiently large distance (30 m) from the source. So, in the near-field area, that is closer than 30 m from the antenna (in both the horizontal and the vertical plane), the strengths of the electric fields are measured. In the far-field areas, that is further than 30 m (in both the horizontal and the vertical plane), the RF EMF power density is measured from the antenna. If the mobile telephony base station antenna is mounted on a building or mast that is higher than 30 m, the RF EMF power density is measured on the ground. The influence of the other base stations in the vicinity is very small (about 1%), so they are not defined. For multiple frequency sources the exposure quotient (\(EQ_{tot}\)) was used to evaluate the public exposure:  
\[EQ_{tot}=\sum_{i=1}^{N}\left(\frac{E_{i}^{mass}}{E_{i}^{guide}}\right)^{2}\]  
where \(N\) = total number of radio frequencies in the evaluation point; \(E_{i}^{meas}\) = value of electrical field component, related to the corresponding frequency \(i\); \(E_{i}^{guide}\) = limit value of electrical field component, according to the guide related to the corresponding frequency \(i\); If \(EQ_{tot}\) is less than 1, then the environment is considered safe against radio frequency radiation [52]. All measurements were performed between 9:00 and 16:00 via a field meter placed on a tripod. Measurements at each selected point were performed in triplicate. Measurements were performed at different heights from the floor, namely 1, 1.5, and 1.7 m. Measurements were done in the far-field of the macrocell mobile telephony base station antennasby using a NBM 550 broadband field meter (Narda, Hauppauge, NY, USA) with an EF 0392 isotropic E-probe and a Narda SRM 3006 selective radiation meter with a 27 MHz-3 GHz isotropic E-probe. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Effective Radiated** & **Height, m** & **Type** & **Technology** & **Measurement Location** \\
**Power (ERP), W** & & & & **(Accessible to the** \\  & & & & **General Public)** \\ \hline
1739 & 12.7 * & KATHREIN & GSM-900, GSM-1800, & On the roof area and on \\  & & 80010292 & UMTS 2100 & the ground \\ \hline
1428 & 20.5 ** & KATHREIN 742241 & GSM-900, GSM-1800, & In residential area \\  & & & & UMTS-2100 & the ground \\
1329 & 33.3 *** & KATHREIN 742241 & GSM-900, GSM-1800, & On the roof area and on \\  & & & & UMTS-2100 & the ground \\ \hline \hline \end{tabular}
* Total: 12.7 m (from the ground to the top of the antenna) = building; 9 m + antenna mast: 2.4 m + the middle of the antenna panel: 1.3 m; ** Total: 20.5 m (from the ground to the top of the antenna) = building: 10 m + antenna mast: 9.5 m + the middle of the antenna panel: 1 m; ** Total: 33.3 m (from the ground to the top of the antenna) = building: 30 m + antenna mast: 2 m + the middle of the antenna panel: 1.3 m.  
\end{table} 
Table 1: Antenna technical specifications. The results presented in Figures 7, 8 and 13 were obtained using a professional broadband field meter (Narda NBM 550) measuring the electric field strength (V/m) (the instantaneous field strength of all signals presented in a large frequency band). The broadband field meter cannot distinguish between signals coming from different transmitting sites. However, this does not cause a great problem when the measuring field levels are in the frame of the exposure guidelines recommended by ICNIRP regulations. The results presented in Figures 9-12 and 14 were obtained with a selective radiation meter (Narda SRM 3006). \"Spatial Averaging\" was used for exposure measurements. Spatial averaging is the technique used to measure field exposure (E) and power density (S) averaged over a number of spatial locations.