This work presents a new rigorous investigation of corona effects in microstrip components. To carry out the investigation, a new software tool has been developed. The new tool first calculates the electromagnetic fields in complex microstrip structures using a Volume Integral Equation (VIE) formulation. Novel numerical techniques have been incorporated in the VIE to increase the accuracy during the computation of the electromagnetic fields. This includes novel techniques introduced to treat the singularities of the Green's functions. Once the electromagnetic fields are computed accurately, corona effects in the relevant structures are investigated. For this, a numerical solution of the free electron density continuity equation has been implemented.The new software developed has been used, for the first time,in the study of corona effects in the neighborhood of coaxial to microstrip transitions, containing flat ribbons. Numerical results are validated through measurements, showing the accuracy of the developed models.