## 4 Experimental Verification and Analysis  
This section describes the anechoic chamber experimental validation and analysis of the beam control and beamforming algorithms designed in Section 3. The experiments included tests on beamforming signal amplitude, beamforming sensitivity, beam uniformity, and beam pointing accuracy, as well as error evaluation and analysis of the algorithms. The experiments were conducted in a microwave anechoic chamber using the three-meter method. The chamber had a shielding effectiveness of \(\geq\)89 dB in the range of 14 kHz to 40 GHz, a normalized site attenuation (NSA) of \(\leq\)4 dB in the range of 30 MHz to 1 GHz, a site voltage standing wave ratio (SVSWR) of \(\leq\)5.5 dB in the range of 1 GHz to 18 GHz, and a field uniformity (FU) of \(\leq\)4 dB in the range of 80 MHz to 18 GHz. The chamber temperature was controlled between 15 \({}^{\circ}\)C and 35 \({}^{\circ}\)C, with relative humidity (RH) maintained between 20% and 80%, and an atmospheric pressure of 101.4 kPa. The RF signal source used was the Agilent E4421B model (Shenzhen, China), and the spectrum analyzer used for measuring line loss was the Rohde & Schwarz FSV model (Shenzhen, China). The actual setup for the anechoic chamber tests is shown in Figure 14, and the equipment connection topology is illustrated in Figure 15.  
shows the waveform of the raw data processed using MATLAB R2017b, Figure 17 illustrates the waveform after weighted phase shifting, and Figure 18 displays the waveform after summation in the desired direction. Figure 16: Original data waveform. Figure 14: Actual scene of an anechoic chamber test. Figure 15: Topology diagram of the connection relationships in the anechoic chamber test. Anechoic chamber test results show that the peak amplitude after beamforming, as illustrated in Figure 18, is 31.76-33.04 times that of a single receiving channel. This result is consistent with the theoretical calculations in Section 2. 2. Beamforming Sensitivity Test  
Sensitivity is defined as the minimum signal power that allows the receiver to meet the capture and tracking criteria (achieving capture, tracking, frame synchronization without losing lock, and a bit error rate better than \(10^{-6}\)). This test evaluates the receiver's sensitivity in beamforming mode. The sensitivity test was conducted for the following elevation and azimuth angles: (\(10^{\circ}\), \(90^{\circ}\)), (\(10^{\circ}\), \(180^{\circ}\)), (\(10^{\circ}\), \(270^{\circ}\)), (\(45^{\circ}\), \(0^{\circ}\)), (\(45^{\circ}\), \(90^{\circ}\)), (\(45^{\circ}\), \(180^{\circ}\)), (\(45^{\circ}\), \(270^{\circ}\)), (\(63^{\circ}\), \(350^{\circ}\)), (\(90^{\circ}\), \(0^{\circ}\)), (\(90^{\circ}\), \(90^{\circ}\)), (\(90^{\circ}\), \(180^{\circ}\)), and (\(90^{\circ}\), \(270^{\circ}\)). Due to the elevation angle coverage range of the array antenna being from \(10^{\circ}\) to \(90^{\circ}\) and the azimuth angle coverage range being from \(0^{\circ}\) to \(360^{\circ}\), selecting these angles roughly covered the entire coverage range of the airspace. Sensitivity tests were performed sequentially for three operating frequencies:  
Right-hand circular polarization at 2294.75 MHz, right-hand circular polarization at 2242.8 MHz, and left-hand circular polarization at 2242 MHz. The test results for carrier-to-noise ratio \(CNR\), bit error rate \(P_{0}\) within one minute, and calculated sensitivity \(P_{\text{min}}\) are summarized in Table 2. The formula for calculating sensitivity \(P_{\text{min}}\) is  
Figure 17: Waveform after weighted phase shift. Figure 18: Waveform after summation in the desired direction.