Transmission properties of a right-angle microstrip bend with and without a miter

The transmission properties of a microstrip bend with and without a miter joint are investigated based on the waveguide model and using the Green´s theorem approach. Unlike the conventional mode-matching technique, this approach does not require a modal description of fields inside the discontinuity region. Instead, the fields on the two sides of the discontinuity are related by applying the Green´s theorem with an appropriate choice of an auxiliary function which plays the role analogous to that of the testing function in the method of moments. The selection of the auxiliary function is not systematic and involves good physical insight to the problem under study. Scattering parameters for the bend are presented which agree well with the quasistatic results at low frequencies. Significant improvement in the transmission properties is observed for the bend with a miter. It is noted that by themselves, the results provide an accuracy check for the more sophisticated integral equation approach which can handle arbitrarily shaped boundaries. Moreover, with a slight modification, this technique may be extended to study microstrip corners with an arbitrary miter.<>