A 22.8-to-43.2GHz tuning-less injection-locked frequency tripler using injection-current boosting with 76.4% locking range for multiband 5G applications

Future cross-network and international roaming are attractive in mm-wave fifth-generation (5G) wireless networks with multiband operations. The generation of an ultra-wide-bandwidth ultra-low-phase-noise (PN) local oscillator (LO) signal in massive multiple-input multiple-output (MIMO) transceivers, which support spectra around 28GHz, 37GHz, and 39GHz, becomes a significant challenge. Injection-locked frequency tripler (ILFT) is a good candidate for LO generation due to its low PN property while suffering from a narrow locking range. Varactors are often used to tune the free-running frequency to increase the bandwidth [1]. However, the PN performance degrades when the target frequency is far away from the free-running frequency, which means a complex calibration mechanism must be applied [2,3]. Meanwhile, an ILFT with such a self-calibration circuit still suffers from a narrow locking range, which cannot support multiband operations. To simplify the system design and meet the multiband requirement, a tuning-less ILFT with an ultra-wide locking range is seen as an appropriate solution for mm-wave multiband 5G applications.