Reconfigurable 40 GHz BiCMOS uniform delay crossbar switch for broadband and wide tuning range narrowband applications

A wide-band crossbar switch configured as a non-blocking signal router can be used in various applications that need reconfigurable digital or analog cross connections such as network switches, CPU-memory connecting modules and wide tuning range radar switches. Current mode logic using IBM 8HP SiGe heterojunction bipolar transistors having f_Ts of 210 GHz and a symmetrical signal path design are employed to make a 40 GHz crossbar switch capable of 80 Gb/s transmission with a fast reconfiguration time of 160 ps. A unique feature of this crossbar is that the delay through any path in the switch is constant. The f_T of IBM´s 8XP SiGe model is 350 GHz, which allows for faster circuits than the 8HP technology. The crossbar switch using IBM´s 8XP kit is simulated to predict further performance improvement to 50 GHz (100 Gb/s for binary signals). To demonstrate the maximum operating speed, the crossbar switch is tested as a 40 GHz phase router for a phased array antenna system. The measured output of the crossbar switch is a 38.8 GHz sine wave with the selected phase delay. The phase noise of the output signal is -88.3 dBc/Hz for an input whose phase noise is -98 dBc/Hz at 1 MHz offset. Using a 2.5 V supply, the 8HP crossbar switch consumes 2.2-5.7 W depending on the number of active channels. The power dissipation of the crossbar switch can be reduced by about 70% with the same performance by using the 8XP kit.