Coplanar MMIC active bandpass filters using negative resistance circuits

A second order active bandpass filter for a fixed centre frequency and a tunable one have been developed in coplanar line technique using negative resistance circuits. These filters operate in the 1.8 GHz band and have a 3 dB bandwidth of 110 MHz. The tuning range of the centre frequency is 200 MHz. Each filter is fabricated on a GaAs substrate and occupies an area of 1.5/spl times/1.6 mm/sup 2/ on the wafer including all biasing elements.<
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