Dr.-Ing. Mohammed Ali

Modern 5G and 6G application require antennas with high ERIP to account for the limited output power of the power amplifiers. Directional antenna arrays are adopted to concentrate the power in a specific direction. Therefore, phased array TRx are employed for 5G systems and beyond. Steering the radiated beams mandates feeding each antenna element by a specific signal phase. Shifting the signal phase of each antenna element is carried out by a phase shifter. Phase shifters such as true time-delay and vector modulator are the common candidates. True time-delay phase shifter is suitable for wide channel bandwidth avoiding beam squinting. They are, however, bulky and loss causes deteriorated system power efficiency. The channel bandwidth is limited by the baseband ADC/DAC, offering the possibility for using vector modulator phase shifter (VMPS). The superposition of quadrature weighted signal is the principle of operation of the VMPS. The precision of the phase shifted signal in terms of phase and amplitude depends on several factors. First, the accuracy of the IQ generated signal, and the precision of the VGA gain selection. In reality, real time calibration is carried out to adjust the phase and amplitude. However, generating high precise phase shifted signals is required to ease the calibration algorithm and improve latency. In this project, focus is to be given to the design of the IQ generation network and the selection of the VGA topology to attain lowest possible rms phase- and amplitude-errors.