## 3 Measurement and Verifications  
To verify the statistical indoor EZ in Section 2, we measured the received power inside the KINS simulator room using the test setup consisting of the dipole antennas, signal generator, power amplifier, and spectrum analyzer. Figure 5 shows the geometry and photograph of the dipole antenna for the received power measurement in the KINS simulator room. The dipole antenna consists of a balun which is embedded in the circuit board to minimize the pattern distortion by the unbalanced current of the coaxial feed. In addition, two metallic wires are connected to the balun through the circuit board with soldering, and each wire's length is 30 mm, as shown in Figure 5. The fabricated dipole is presented in Figure 5, which is fabricated as a pair for use as the transmitting and receiving antennas, respectively. Figure 4: Comparisons of statistical indoor EZs according to transmitting antenna positions: (**a**) _Tx._ 1; (**b**) _Tx._ 2. Figure 5: Geometry and photograph of the dipole antenna: (**a**) geometry; (**b**) photograph. Figure 6 provides the reflection coefficients and radiation patterns of the dipole antenna. In Figure 6a, the solid line and the dashed line indicate the measured and simulated reflection coefficient, respectively. The measured and simulated reflection coefficients are \(-30\) dB and \(-17\) dB at 2.4 GHz, respectively, which show a low reflection characteristic of less than \(-10\) dB at the operating frequency. In Figure 6b, the measured radiation patterns have an omni-directional property with an average gain of around 0 dB in the azimuth plane, which is suitable for use as a probe capable of measuring the received power in all directions. Figure 7 shows the test setup for measuring the indoor received power. In the test setup, the signal generator capable of creating electromagnetic waves at 2.4 GHz is employed. However, the signal generator does not have enough power to transmit the signal to a faraway receiving antenna. Therefore, the output power (0 dBm) of the signal generator is amplified through a power amplifier with a gain of 30 dB. Then, the input power of 1 W (30 dBm) is finally delivered to the transmitting dipole antenna. Herein, the amplified signal is radiated through the transmitting dipole antenna, and, simultaneously, the spectrum analyzer with the receiving dipole antenna observes the received power. Figure 8 presents the comparison of the measured and simulated received power according to the distance between the transmitting and receiving antenna when the transmitting antenna is placed at \(Tx\). 2. The blue '\(\times\)' markers indicate the measured data, and the  
Figure 6: Reflection coefficients and radiation patterns of the dipole antenna: (**a**) reflection coefficient; (**b**) radiation pattern. Figure 7: Test setup for the indoor received power measurement. black 'o' markers are the simulated data. The received power is measured at 60 cm intervals according to the distance from the transmitting antenna (\(Tx\). 2), and it is examined for two regions of _Region 3_ (Figure 8a) and _Region 7_ (Figure 8b). In Figure 8a, the measured received power has a distribution range from \(-23.5\) dBm to \(-7\) dBm, which agrees well with the simulated data. The measured received power in Figure 8b is distributed from \(-31.5\) dBm to \(-8.5\) dBm. The results demonstrate that the proposed statistical indoor EZ can be properly obtained not only from the simulation data but also from the measurement data. Figure 9 presents an RMSE according to the sampling interval, which can explain how many samples are needed to provide a reliable estimation of the EZ. To obtain this result, we adjusted the sampling interval from 0.1 m to 0.9 m based on the simulation results, where the area of the EZ is calculated for each case. Herein, RMSE is obtained by examining the EZ area difference between the case of Figure 4 (sampling interval of 0.1 m) and other cases (sampling interval from 0.2 to 0.9 m).