Design and implementation of second-order microwave integrator

Abstract

ABSTRACTIn this paper, a new design methodology is developed for the implementation of a second-order microwave integrator on microstrip circuit. Firstly, an existing digital first-order integrator with best magnitude and phase performance is adopted as a prototype to give digital second-order integrator transfer function. Then, by using the autoregressive process and a least mean square based error function, coefficients of the formulated second-order digital integrator are transformed into the impedance values of transmission line elements. Different sets of impedance values are obtained through the optimization process, and design with a highly accurate frequency response having maximum relative error value not more than 7.2% over the angular frequency range 0.18pi to 0.94pi is selected for implementation purpose. RT/Duroid 5880 is used to fabricate the proposed second-order microwave integrator design. Measured results for transmission coefficient S21(f) are found to follow theoretical values over the frequency range of 1.8 GHz to 8.6 GHz.