Innovative Hybrid RC-AC Test Environments and RIS-Enabled Plane Wave Generation

Journal article, 2024

This paper provides a brief overview of two new concepts of plane wave generators (PWGs) for applications in antenna and wireless device measurements. These PWGs aim to increase flexibility in emulating various multipath testing conditions within the same measurement environment, addressing the high cost and complexity of conventional systems. The first concept, utilizing a chamber antenna array (CAA) inside an overmoded waveguide (WG), leverages the reflecting walls of the metal rectangular WG in conjunction with a CAA to synthesize obliquely incident plane-wave fields at the device under test. This has been demonstrated for telecom sub-6 GHz applications (e.g., for total radiated power and pattern measurements), with ongoing studies on its evolution to Reconfigurable Intelligent Surface (RIS) based PWGs for millimeter-wave frequencies. We discuss the design and analysis foundations, highlighting key requirements and limitations to maximize flexibility. We use simulations with a customized modeling framework and measurements from our first prototype systems: an overloaded waveguide (WG) chamber with a 6 ×7 CAA at 915 MHz and a 16 × 16 RIS PWG at 28 GHz. WG-based PWG is evaluated using metrics such as uniformity, angular spread, and bandwidth. For the RIS PWG prototype, we demonstrate the practically achievable complex reflection coefficient values to evaluate the requirements for PWG applications.