A Novel Approach to the Characterization and Modelig of Microwave Transistor Packages

A novel approach to the characterization and modeling of microwave transistor packages through dedicated VNA measurements is presented. By combining a multi-step partitioning method with the use of purposely realized - but technologically simple - "package style" test devices, the proposed technique permits to derive in a systematic manner an equivalent circuit for both the transistor package and the test-fixture mount employed for the characterization. Since it does not rely on the indirect, optimization-based, conventional extraction methods of the literature, nor on a simplified circuit structure for the overall parasitic fourport embedding the active device, it is able to provide a higher confidence and precision level on the determination of the transistor chip parameters, which can be exploited for both device diagnostics and nonlinear modeling purposes. As a practical application and verification of the proposed method, experimental results pertaining to the case of a 100 mil ceramic package (by Mitsubishi) mounted in a coaxial transistor test-fixture (by HP/Maury) are reported, showing that accurate modeling up to K-band can be achieved with limited effort.