Similar to 5G networks and devices supporting mmWave frequencies, antenna systems and RF transceiver modules for future mobile communications standards or automotive radar applications will share the same features that make their testing a challenge. Their wide frequency range, a greater number of antenna elements and the lack of conventional external RF connectors will demand testing over-the-air in a shielded environment. Wireless communications test expert Rohde & Schwarz and IHP GmbH (Innovations for High Performance Microelectronics) have transferred this test method successfully into sub-THz range: They demonstrated the first full 2D/3D over-the-air measurements of a radar module at D-Band frequencies.
The test setup consists of the R&S ATS1000 antenna test system, the R&S ZNA43 vector network analyzer and the R&S AMS32 antenna measurement software from Rohde & Schwarz. The R&S ATS1000 antenna test system is a compact and mobile shielded chamber solution for OTA and antenna measurements, ideal for 5G mmWave applications. To cover the D-Band frequencies, extensions from Radiometer Physics GmbH, a Rohde & Schwarz company, are used in the setup, which allow direct frequency conversion at the probe in both transmit and receive directions. No mechanical modifications or additional RF cabling to the antenna test system is necessary. The setup can measure the amplitude and phase coherent response of a DUT radiating in the D-Band. Fully automated 3D-pattern measurements including post-processing can be performed in short time thanks to the R&S AMS32 software options for nearfield to farfield transformation and the highly accurate precision positioner.
IHP provided four different devices under test (DUT), based on the same D-Band radar transceiver chipset but with different antenna structures, including on-chip single and stacked patches with air trenches and an on-chip antenna array. The over-the-air characterization verified the wider bandwidth provided by the stacked patches than that by the single patch.
The performance of the various DUTs was characterized by spherical measurements, using two different setups. By increasing the angular theta step-size from 1 degree to 5 degree, the total test times for a DUT could be reduced from 70 minutes to 12 minutes. By comparing the different DUT designs based on the obtained measurement data, researchers of IHP were able to analyze the effect of the finite on-board reflector area on the radar sensor FoV (field-of-view).
Prof. Gerhard Kahmen, Managing Director of IHP, says: “Sub-THz frequency systems are getting more and more attention in research and many fields of application. The Rohde & Schwarz OTA test system, extended to D-Band, provides an excellent way to characterize radiation patterns of the complex antenna structures, realized in our D-Band radar chips, in a time efficient and precise way. For IHP, these measurements are valuable to understand the physics of the antenna structures and to further improve their performance. The very successful cooperation with an industrial partner leading in the field of wireless and mmWave communication shows the benefit of close interaction between research and application.”
Alexander Pabst, Vice President of Systems & Projects at Rohde & Schwarz says: “We are excited to work with such an excellent partner as Innovations for High Performance Microelectronics on advancing our industry-leading test solutions for over-the-air testing. These joint efforts will help researchers and key industry players to test and characterize antenna systems and transceiver modules for future automotive radar applications and wireless communication standard, that we eventually call 6G.”
For further information on OTA measurements in the D-Band, watch the video at: https://www.rohde-schwarz.com/_251220-987264.html
To learn more about of the initiatives of Rohde & Schwarz beyond 5G, go to https://www.rohde-schwarz.com/wireless/B5G
The IHP – Innovations for High Performance Microelectronics is a non-university research facility and belongs to the Leibniz Association. Thanks to its closely interlinked and coordinated research programs: materials for micro and nanoelectronics, technologies for smart systems, high-frequency circuits, system architectures and wireless systems, the institute is one of the world’s most important players in the field of silicon-based high frequency microelectronics. As a transition between basic research and application-related applications, IHP makes significant contributions to the innovative strength and ability of Germany and Europe as a location.
Rohde & Schwarz is a leading supplier of solutions in the fields of test and measurement, broadcast and media, aerospace | defense | security and networks and cybersecurity. The technology group’s innovative communications, information and security products help industry and government customers ensure a safer and connected world. On June 30, 2020, Rohde & Schwarz had about 12,300 employees worldwide. The independent group achieved a net revenue of EUR 2.58 billion in the 2019/2020 fiscal year (July to June). The company is headquartered in Munich, Germany, and has subsidiaries in more than 70 countries, with regional hubs in Asia and America.
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