5G (26 GHz) iletişim sistemleri için frekans sentezleyici ve karıştırıcı tasarımı

Next generation 5G wireless mobile communications systems aim to address the increased demands for high data rates by utilizing the large bandwidths available at mmWave frequencies such as the 26 GHz band (24.25 – 27.5 GHz). Directive communications using highly directive beams will become proliferated at these frequencies in order to overcome the increased path loss at mmWave frequencies. Beamforming technology is poised to find widespread adoption for directive communications. Beamforming transceivers require frequency translation from high frequencies to baseband and vice-versa. The frequency translation is performed using mixers and frequency synthesizers. In this thesis, the design of high linearity downconversion mixers suitable for 5G (26 GHz) beamforming receivers is investigated. The design of frequency synthesizers that provide the LO signal for mixers and are required for frequency translation in transceivers is also investigated. The building blocks for an integer-N 4th order type-II PLL is designed for 26 GHz 5G frequency synthesis applications. The designs are realized using IHP's 0.13 $\mu$m SiGe BiCMOS technology. The presented high linearity Gilbert-cell active downconversion mixer is fully integrated with power combiners and baluns and hence is suitable for beamforming applications. The mixer achieves an input 1-dB compression level of up to 2.6 dBm while featuring a low conversion loss of 2.5 dB. The mixer consumes 19 mW dc power and occupies an area of 3.18 mm$^2$. The proposed bias decoupled cross coupled HBT VCO for the PLL is simulated to have a phase noise of -116 dBc/Hz @ 1 MHz offset from a 10.5 GHz carrier while achieving a tuning range of 19\% from 9.4 GHz to 11.4 GHz. The PLL has a simulated phase noise of -98 dBc/Hz @ 1MHz offset from a 10.5 GHz carrier and an estimated RMS phase jitter of 301 fs.