ACTIVE GAAS MMIC BAND-PASS FILTERS WITH AUTOMATIC FREQUENCY TUNING AND INSERTION LOSS CONTROL

This paper presents the design and measured performance of active tunable band-pass MMIC filters and matched MMIC control circuits, both fabricated using a standard 1-mu m GaAs MESFET foundry process, The control circuits generate filter frequency-tuning and Q-control bias voltages by using a dual-loop master-slave control scheme, Separate 3-section filters cover 1.5-2.0 and 1.96-2.64-GHz bands with 3-dB bandwidths of 86+/-6 and 126+/-10 MHz, respectively, The control circuits automatically maintain the filter insertion loss to within +/-0.5 dB over these tuning ranges, and regulate the center frequency and insertion loss to within better than +/-1.2 MHz and +/-0.3 dB over a temperature range of -50 degrees C to +75 degrees C.