A triple mode wide locking range, low phase noise injection locked oscillator based phase shifter covering the Sub-6 GHz 5G bands

Multiple-input and multiple-output (MIMO) systems with antenna arrays are a key enabling technology for upcoming 5G networks. It is predicted that initially most 5G networks will consist of the Sub-6 GHz spectrum bands. In such a phased array system the phase shifter will be the key component which is used to steer the beam. In this work we propose using an injection locked oscillator based phase shifter (ILPS) with a locking range wide enough to cover the entire Sub-6 GHz 5G bands without discontinuity. The work is based on a triple resonant frequency transformer resonator using a CMOS oscillator. Excellent tradeoff between locking range and phase noise performance has been achieved. The proposed ILPS has a locking range of 3.0GHz, 2.5GHz and 4GHz corresponding to center frequencies of 2.7GHz, 3.3GHz and 4.2GHz. Input injection power is 0 dBm. It also provides a low phase noise variation of 1.8dB (-141.2 to -139.4 dBc/Hz at 1 MHz offset) in all sub-bands under locked condition. Tuning phase shift range of 180 ⁰ is achieved .The ILPS is implemented in a 90 nm RF CMOS process that consumes 25 mW of DC power under a 1.8V supply.