Interpretation of 5G modulation signals and continuous wave signals
[Copy link]
Interpretation of 5G modulation signals and continuous wave signals
Author: ETS Source: Breadboard
Power Density Assessment Using Near-Field Measurements of Electric and Magnetic Field Decoupling 5G Modulated Signals and Continuous Wave Signals
Abstract—New 5G technologies promise fast and reliable data transfer for the next generation of communications . To enhance the quality of wireless networks, the latest technologies are being developed. One of the most prominent technical highlights is the use of wideband waveforms in combination with millimeter wave frequency bands. For new wideband antennas operating at frequencies above 20 GHz, this will be a great challenge as it requires precise and complex data processing capabilities. This paper compares two modes of testing decoupling the electric (E) and magnetic fields (H) of an off-the-shelf wideband horn antenna. One is that the antenna transmits a wideband modulated signal. The other is that a continuous wave is transmitted in the 5G New Radio (NR) FR2 band with a center frequency of 28 GHz. [ Index Terms—5G, Electric and Magnetic Field Decoupling, Near-Field Measurements, Wideband Waveforms] Introduction— A key feature for any 5G wireless network is the stability and flatness of the data throughput on a wideband modulated signal. Therefore, it is crucial to have a wideband transmission device that can generate the same level of signal for all aggregated carriers at the same time. If some carrier blocks do not carry enough power, the information on the carrier will not be transmitted completely and the entire data set will be corrupted. Therefore, verifying the performance of broadband antennas when transmitting modulated signals is very important for antenna designers and manufacturers. Evaluation of the antenna in the near field region provides comprehensive information about the signal composition process. In the near field region, the electric and magnetic field waves are not in phase and the propagation direction is not linear [1]. Therefore, independent evaluation of the E and H vector distributions on the evaluation plane is required, which is a new antenna performance evaluation method. The double probe method used here is described in detail in [2] and [3]. The power density will be calculated using the Poynting vector formula [4]. The object of the study is an off - the-shelf conical horn antenna operating in the frequency range of 22 GHz to 33 GHz. It is tested in two modes: 1) an 8-carrier modulated signal with a bandwidth of 800 MHz and a center frequency of 28 GHz (Figure 1) 2) a continuous wave signal in the frequency range of 27.960 GHz to 28.400 GHz.
Test setup overview:
1) The vector signal generator is used as a modulation source to send a signal to the antenna, while the E or H probe is connected to the spectrum analyzer .
2) Connect the 2-port vector network analyzer with the antenna connected to port 1 and the E or H probe connected to port 2 (Figure 2
The evaluation was performed at a height of 10 mm (1 wavelength) from the antenna aperture plane, with a scanning step of 2 mm and a probe rotation step of 30 degrees.
Test Results and Observations:
Figure 3 shows the E electric field. The signal level of carrier 5 is more than 3dB lower than that of carriers 1, 2, and 3, and more than 5dB lower than that of carriers 7 and 8. The difference in electric field distribution is very serious and sufficient to affect the transmission quality of all carriers.
Figure 4 shows the result under the H magnetic field. It can be seen that carriers 1, 2, and 3 are 3dB lower than carriers 5, 6, 7, and 8. The distribution of different carriers in the H magnetic field is also inconsistent. And to some extent, it is also obviously inconsistent with the error of the E electric field.
This difference in signal level on different carriers is so obvious and serious that it often causes amplified errors in power density calculation , especially in the early stage of signal transmission. Therefore, transmission with different power densities through different carriers will actually lead to information loss of the sending device.
Continuous wave signal:
In CW mode, the amplitude and phase are evaluated at each measurement frequency, and the field and phase distributions at the center frequency of each carrier are calculated. In each case, the modulation signal bandwidth of each carrier is used as a reference to calculate the field and phase distributions of the CW signal of the corresponding carrier (Figure 5). The
gradual evolution of the amplitude and phase distribution of the CW field distribution is consistent with the theoretical E electric field and H magnetic field distribution.
Power density
每个载波的调制信号被计算出其功率密度后，依次针对对应的载波连续波信号计算功率密度。
从载波1开始到载波8，就算离开天线一个波长，传送信号的中心叶仍未成形，载波与载波的峰值位置也仍然是在变化中的。
呈现的图(图6)展示了调制信号和连续波信号在载波之间的差异。功率密度值分析(图7)显示调制信号和CW连续信号之间是没有相关性。从(图８)在计算整个调制信号和相应连续波信号的功率密度後也显示出峰值位置，面积平均功率密度和发射功率等都存在差异性。
Summarize
The study revealed contradictory test results when using modulated signals on horn antennas. No significant correlation was found between the two test modes. Therefore, testing of antennas using continuous waves was deemed inadequate to predict the performance of antennas when modulated signals were transmitted.
I am KeCeJun~Testing has never been so easy
| 
提升卡
变色卡
千斤顶
