With the rise of 5G NR technology, the adoption of new, complex technologies, such as beamforming, sophisticated antenna array systems and new usable communications spectrum, including mmWave is set to increase too. For mmWave, every device will have to be tested over the air (OTA), without any cable connections. To address these challenges, Rohde & Schwarz has created industry-leading OTA test solutions that are on display at Mobile World Congress in Barcelona.
5G NR provides numerous technological advantages, but there will also be many technical challenges that need to be overcome during 5G NR testing. Since OTA measurements often require far field conditions in order to be carried out fast, easily and accurately, a high-quality quiet zone (QZ) is needed in which the wave fronts coming from a test antenna can be assumed to be plane. Larger QZs (Quiet Zones) require a long distance between the device under test (DUT) and the test antenna, meaning large shielded chambers are needed in direct far field (DFF) setups. Conformance testing in the mmWave range also calls for black box testing, meaning the location and size of the antennas in OTA measurements are considered unknown.
To address the space constraints, Rohde & Schwarz employs the Compact Antenna Test Range (CATR) method, which has been approved by 3GPP. The method relies on indirect far field (IFF) technology to simulate far field conditions. The reflector used in a CATR setup transforms the incoming spherical wave front to a plane wave due to its parabolic shape. This requires extremely high precision in reflector manufacturing, with accuracy in the micrometer range. To achieve this high accuracy, Rohde & Schwarz has developed an innovative, fully automated manufacturing method, delivering considerably higher reproducibility than traditional, semi-automated processes.
Conformance Testing with the New R&S ATS1800C
Conformance testing is crucial in order to ensure that a device conforms to specifications, standards and regulations. Among the highlights, Rohde & Schwarz has premiered the R&S ATS1800C, a fully anechoic mmWave CATR solution and a turnkey high-end system for conformance and compliance testing. It uses IFF technology and provides a sophisticated, state-of-the-art RF test solution. The innovative manufacturing method for the reflector results in a high-quality QZ and therefore reproducible measurements. Unlike similar CATR solutions on the market, the ATS1800C features a vertical layout, i.e. the positioner, feed antenna and reflector are arranged vertically, taking up only half the floor space and fitting next to a standard 19" rack.
Among the accessories available for the system is the T3O110 phantom series, including head and hands for 5G OTA, manufactured by the Swiss company SPEAG. These phantoms are based on a novel technology that replicates the layered structure of the human skin and simulates its RF properties up to 110 GHz. The phantoms are used to reproduce a realistic loading of the DUT and energy absorption of a human hand and head and are necessary to evaluate performance of the DUT in authentic use cases.
Compact, High-Performance Solution for R&D Testing
For general-purpose R&D testing, Rohde & Schwarz has introduced the R&S ATS800R. This solution uses a fully anechoic, compact shielding chamber accommodated inside a standard rack. The DUT can be positioned at an ergonomic height. The system also employs a high-grade, medium-sized CATR reflector delivering a QZ of optimal quality. This makes the ATS800R one of the world's most compact CATR systems for mmWave tests, providing a high-performance option for R&D measurements and optimally utilizing the available space by using a standard rack instead of a dedicated shielding chamber.
OTA and Thermal Effects Diagnostics in One Package
Thermal effects diagnostics on DUTs are crucial when analyzing chipset and UE performance since device heating or cooling can affect the RF components and consequently the radiation pattern of the antennas. Rohde & Schwarz has developed a setup that enables 3D RF measurements of antenna characteristics in a temperature range from –40 °C to +85 °C. Integrating the R&S ATS-TEMP climate option into an ATS1000 antenna test system makes it possible for the first time to combine testing in an RF OTA chamber and climatic chamber testing into a single procedure.
Fully integrated, Compact OTA Test Solution for 5G FR2 Devices
Rohde & Schwarz is also exhibiting a new solution for testing large volumes of FR2 devices. The solution consists of an R&S CMP200 radio communication tester and an R&S CMQ200 shielding cube. The CMP200 combines vector signal analyzer and ARB generator functionality. The 2 RU one-box-solution can be customized with up to three R&S CMPHEAD30 remote radio heads (RRH) for up- and down-converting signals to 5G FR2 frequencies. The CMQ200 is a compact, flexible 19" shielding solution that can accommodate most 5G devices in different applications. With the CMP200 and the CMQ200, Rohde & Schwarz is offering its customers a fully integrated, single-source solution that delivers reliable, reproducible results for radiated measurements.
Rohde & Schwarz, is in Hall 6 at Mobile World Congress this week. Stop by their booth to see these solutions.
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