13-bit GaAs serial-to-parallel converter with compact layout for core-chip applications

Design and characterization of a 13 bit serial-to-parallel converter in GaAs technology for smart antennas are presented. The circuit has been realized with NOR-based super-buffered enhancement/depletion logic, and optimized for a compact layout. The serial-to-parallel converter operates properly well above the 20 kHz design clock frequency.     

Compensating for parasitic phase shift in microwave digitally controlled attenuators

Design issues of digitally controlled attenuators are considered: the parasitic phase shift effect, occurring with every change in the attenuator cell state, is highlighted, investigated and corrected. The technique adopted consists of inserting an appropriately sized capacitor in the attenuator cell topology, compensating for the above-mentioned parasitic phase shift. A design equation is inferred and an X-band MMIC 5-bit constant phase digital attenuator is designed as a test vehicle for the proposed approach.     

High-power monolithic AlGaN/GaN HEMT switch for X-band applications

The design, fabrication and test of X-band high-power monolithic SPDT switches in microstrip GaN technology are presented. Such switches have demonstrated state-of-the-art performance: they exhibit 1 dB on-state insertion loss and better than 37 dB isolation. Power- handling measurements have shown that no compression phenomenon occurs with an input power equal to 39.5 dBm at 10 GHz.