Low noise and frequency tunable microwave active recursive filters using power summation principles

In this paper, a noise analysis is performed for frequency tunable active recursive filters using a noise wave formalism approach. The translation of low frequency recursive concepts is done by the use of power dividers/combiners at microwave frequencies. We then derive the characteristics of the amplifier/phase shifter employed within the filter to obtain the optimum noise factor of the structure. A MMIC chip is realized. Layout and measurements of the chip are presented.