Measurement method for characterizing a millimeter-wave traveling-wave power combiner using in-situ test accessories

Abstract

AbstractThis paper presents a novel assessment method that minimizes test-fixture-induced errors in non-coaxial power combiner measurement by extending the port reduction method. This method involves terminating certain ports to acquire the scattering matrix of an N-port network from the scattering matrix measured at a reduced port order. The entire DUT scattering matrix is obtained from multiple scanning measurements, which are taken from partial coaxial accessible ports, based on a set of configurable terminating states. This advantage is leveraged to exclude a major portion of coaxial launch structures that would otherwise be incorporated in the conventional multiport test fixture. An analogous concept here is applied to measure a waveguide traveling-wave power combiner. A sandwiched twin structure, containing a divider/combiner pair with certain auxiliary through-type components cushioned between them, is utilized to assess the combiner characteristics. A theoretical framework of the proposed method was established to test its potential precision. Thereafter, an in-situ implementation was conducted to test its practical application on a traveling-wave combined amplifier prototype operating at the Q-band (33–39 GHz).