Test Method For De-embedding Symmetric And Asymmetric Fixtures In 5G mm-Wave Advanced Antenna System

Sammanfattning: Recent development in the mobile technologies such as 4G, 5G and upcoming 6G requires Advanced Antenna System (AAS) for large-scale deployments. AAS operates at mm-wave frequencies to meet the demand for high data rate, better coverage and improved end-user experience. The AAS are used for performing beam-forming and MIMO's (Multiple Input Multiple Output) operations which make AAS a highly integrated and complex system. Hence it becomes crucial to analyze the performance of sub-systems embedded in AAS. Sometimes it becomes difficult to analyze the performance of such subsystems or Device Under Test (DUT) or Unit Under Test (UUT) due to their non-coaxial interface, whereas most of the measuring equipment has only coaxial connectors in it. One possibility is to add extra fixtures (adaptors or connectors) to the DUT that can convert the DUT non-coaxial interface to a coaxial interface that can easily connect the measuring equipment. However, these fixtures affect results while measuring the performance of the DUT. Therefore, it becomes important to remove the effect of these extra fixtures from the complete measurements which include DUT and fixtures. In literature, there are some well-known developed test methods for de-embedding the symmetric fixtures from the complete DUT measurements. However, no such available test methods for de-embedding the asymmetric fixtures, to the best of the author's knowledge. In most of the practical AAS scenarios, DUT's are embedded in the asymmetric fixtures due to the complex and highly integrated requirement in AAS. Therefore, it's crucial to develop a test method for de-embedding asymmetric fixtures from the DUT measurements. In this thesis work, a test method was developed for de-embedding both symmetric and asymmetric fixtures and implemented in MATLAB. TRL (Thru-Reflect-Line) calibration kits were used to shift the reference planes of the measuring instrument to the desired reference plane of DUT, this will remove the effects of the fixtures from the complete measurements and provides accurate performance of the DUT. The developed method in this thesis work was motivated by the TRL standards and the methodology was developed for estimating fixtures for both symmetric and asymmetric cases. Using the mirror-imaging concept two TRL calibration kits are developed and using these calibration standards characteristics of the fixtures i.e ([TA]) and ([TB]) matrices are obtained. In the end, the developed method was tested and verified on the four different test scenarios using the full-wave simulation models.