Millimeter-wave Power Amplifier Design For Communications

With the growing demands for communication speed,the abundant unutilized bandwidth in millimeter-wave frequencies is gaining increased attention.Early research into millimeter-wave power amplifiers has resulted in several achievements,with some of the designs already applied in commercial products.Nevertheless,there are still some challenges in realizing high-performance,low-cost,reliable,and application-oriented power amplifiers.Based on the re-view of millimeter-wave power amplifier design techniques,solutions to receiver-band noise attenuation,wideband operation,and d B-linear power detection are discussed.The design methodology of a wideband power amplifier is presented to simultaneously satisfy 5G millimeter-wave and Ka-band satellite communication application requirements.With the use of weakly-coupled transformers,harmonic control circuits,and the optimization of active and passive devices,the designed power amplifier maintains a balanced gain,bandwidth,and linearity performance.In the simulation,the implemented power amplifier has a 3-d B bandwidth from 22.7 to 33.5 GHz,covering the majority of the 5G millimeter-wave and the Ka-band satellite communication bands.While providing a saturated output power of around12 d Bm,the power amplifier has a maximal power-added efficiency of 38%,which is suitable for large-scale phased array applications.Furthermore,to monitor the output power,a d B-linear power detector is integrated into the output matching network of the power amplifier,offering around 30-d B detecting range.In the Ku-band satellite communication applications,the frequency spacing between the transmitter and receiver bands is relatively narrow.Through spatial coupling,the receiver-band noise of the large-scale phased-array transmitter could deteriorate the sensitivity and signal-to-noise ratio of the nearby receiver array.To address the problem,a noise-filtering approach by adding a notch filter at the inter-stage matching network of the power amplifier is proposed.To maximize the noise rejection and minimize the notch filter's insertion loss,a series-shunt LC notch filter is applied at the primary coil of the inter-stage matching transformer.The quality factor of the resonator tank is maximized by co-optimize the passive devices.Implemented in65-nm bulk CMOS technology,the designed power amplifier occupies a core area of 0.35×0.85mm~2.In the measurement,the power amplifier demonstrates a 3-d B bandwidth from 13.7 to16.7 GHz with a saturated output power of 14.5 d Bm and a peak power-added efficiency of 24.1%.In the frequency range of 10 to 12 GHz,a maximal noise attenuation of 30 dB is achieved.