A wideband fully integrated SiGe chipset for high data rate communication at 240 GHz

This paper presents a fully integrated direct-conversion quadrature transmitter and receiver chipset at 240 GHz in a 0.13 μm SiGe HBT technology with f
T
/f
max
of 350/550 GHz. This chipset is suited for applications requiring both fixed and tunable LO which is made possible due to a wideband frequency multiplier (×16) based local-oscillator (LO) signal source and a wideband on-chip antenna designed to be used with an external replaceable silicon lens. The Tx can deliver up to 6 dBm output power at 240 GHz and the 3-dB bandwidth is 40 GHz. For the Rx, the peak conversion gain is 10 dB and the NF is 15 dB while the 3-dB bandwidth is 28 GHz. The chipset is integrated in a low loss Rogers 4350B COB (chip-onboard) packaging. For communication applications where high IF bandwidth is required, stepped impedance low-pass filters with minimum group delay variations were implemented on the PCB to negate the low-pass characteristics introduced by the bondwire. The measured 6-dB IF bandwidth is 13 GHz. By using this chipset for high data rate communication, the measured EVM for BPSK modulation is 24% at 20 Gbps while the EVM is 30% at 25 Gbps. For the QPSK modulation scheme, an EVM of 24% is measured at 24 Gbps. These results are for a link of 70 cm and without calibrating the effect of the IF cables and without any channel equalization.