Aug. 07, 2023 Source： Bojay
With the development of 5G applications, the development of millimeter bands is also getting deeper and deeper, and the highest frequency has reached 52.6GHz. The higher the frequency and the wider the application bandwidth become the main characteristics of the 5G millimeter wave new air port, so the 5G millimeter band needs to adopt a multi-antenna design scheme to ensure the quality and stability of the transmitted signal. This also makes OTA testing the main means of 5G millimeter wave RF index evaluation.
OTA testing is a test conducted in a wireless environment to evaluate the performance of a wireless device in a real-world environment. In the radiating far-field area, the antenna pattern changes little with distance, and the field strength is relatively stable, so the far-field measurement method is used in the general antenna pattern measurement.
In OTA testing of 5G millimeter band, the challenge is that with the increase of frequency, space loss and transmission line loss are increasing, especially when out-of-band stray and other indicators are tested, it is becoming more and more difficult to accurately obtain frequency signals. At the same time, due to the large-scale MIMO design, the test complexity is greatly increased for the terminal. In particular, the test of large scatterers and large aperture antennas requires more complex and strict requirements for test instruments, test hardware and test sites, and requires advanced test equipment and technical means to ensure the accuracy and reliability of test results.
Since 2018, Bojay has successfully cooperated with the world's top customers to develop a radio frequency test system that can meet 5G standard applications, and has been widely used in a number of world-class customer laboratories. In the face of the challenges of 5G millimeter band OTA testing, Bojay has independently developed a millimeter wave compact field/far field two-in-one test solution. The system consists of three main components: millimeter wave test box, direct far-field test kit and compact field test kit.
The MMwave test box operates with a bandwidth of 24-90GHz, covering all application bands of 5G MMwave and mmwave radar. It is equipped with a multi-axis rotating test platform, which can be compatible with a maximum of 4-axis mobile rotating platform, and the rotation accuracy can reach ±0.1°. The direct far-field test suite is equipped with a multi-antenna test rack to support complex beamforming tests of MMwave massive MIMO antenna modules. In the far-field test, the test system of Bojay Shares can support the maximum far-field distance requirement of 2000mm.
The compact field test kit is a test system with small footprint and short transmission distance, which is mainly used in millimeter wave radar product and its group test, millimeter wave antenna test and other millimeter wave active/passive product test. The design principle is to use high-precision parabolic reflector to convert the spherical wave radiated by the feed antenna into the plane wave simulating the far field in a short distance. Its core is the high precision reflector and feed.
Bojay has independently developed ultra-broadband and high-precision paraboloid flanged reflector, which supports the frequency band 24-90GHz, the static zone covers 200-400mm, and adopts the manufacturing mode of integrated processing, which ensures the processing accuracy of the paraboloid to a great extent, and the surface roughness is < 20um (RMS). In terms of the matching application of the feed, Bojay adopts the self-developed bias feed, which supports the frequency band 24-50GHz, and can support the testing of both active and passive devices.
Compared with the direct far field, the compressed field greatly shortens the distance of the traditional far field test, which brings great convenience to the test of large objects such as large scatterers. The test distance is shortened, the loss is greatly reduced, and the test dynamic range is larger than the direct far field. The high-precision reflector adopts the design scheme of rolling edge, which not only solves the influence of the diffraction field at the edge of the reflector on the system, but also greatly reduces the size of the reflector compared with the sawtooth edge reflector, reduces the cost and increases the appearance.
Based on the strong research and development capabilities of Bojay, overcoming the technical barriers of feeders and reflectors, our MMwave compact field test system has significant advantages in terms of performance and cost, which can provide a more convenient and efficient solution for your mmwave test.
With nearly 20 years of research and development experience in the field of RF testing, Bojay has been deeply engaged in the field of consumer electronics and automotive electronics, providing system-level solutions in the fields of cellular, Bluetooth, WIFI, ADAS, etc., opening a new chapter in the industry for the promotion and development of future communication technology applications.