TRL calibration kit for characterizing waveguide-embedded microstrip circuits at millimeter-wave frequencies

The calibration and measurement problem at millimeter-wave frequencies of planar devices and MMICs inserted in waveguides is investigated in this paper. A planar structure that operate inside of a waveguide presents characterization problems, in terms of scattering parameters, due to the field geometry dependence. A new TRL calibration kit including a high performance waveguide to microstrip transition included and calibration elements for a complete TRL calibration are proposed. A unique fixture that reproduces the original field geometry for an optimum device characterization is presented. Advantageous features of the proposed calibration kit and fixture suggest its practical usefulness and high accuracy in the design and the optimization of monolithic microwave integrated circuits (MMIC´s) and hybrid microwave integrated circuits (HMIC´s). Appropriate calibration and measurement strategies with mounting details are also shown.