A 71–86-GHz Phased Array Transceiver Using Wideband Injection-Locked Oscillator Phase Shifters

This paper presents the first phased array transceiver operating from 71 to 86 GHz using injection-locked oscillators (ILOs) for phase shifting. A folded-cascode ILO is proposed to extend the locking range of an array of oscillators. Frequency multiplication covers a 10-GHz tuning range with 23-dB power gain. Each ILO path covers more than ±300° and exhibits low amplitude variation with respect to phase shift range (<;1 dB) and excellent isolation and amplitude error (<;0.5 dB) between array elements. A wideband, bidirectional RF front end delivers 10-dBm maximum output power with more than 20-dB conversion gain over the 3-dB bandwidth in the transmit (TX) mode and a minimum 9.5-dB noise figure with more than 20-dB conversion gain in the receive (RX) mode. Low phase noise is demonstrated in the ILO approach over the phase tuning range with -112 dBc/Hz at 1-MHz offset and phase noise variation for different phase shift states under 2.5 dB, corresponding to less than 2° phase error. Array patterns demonstrate the wide scan range, and dynamic measurements show that the transmitter supports up to 6-Gb/s data rate with 256 QAM. The chip has 3.4 × 2.1 mm
²
area implementing in the 90-nm BiCMOS technology and consuming 386.4 mW in the TX mode and 286 mW in the RX mode per element.