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 fTs 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 fT 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 288.3 dBc/Hz for an input whose phase noise is 298 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.