D-BAND POWER MIXER DESIGN FOR 5G APPLICATIONS

The increase of mobile data traffic and connection of billions of Internet of Things (IoT), Internet of Vehicles (IoV), Virtual Reality (VR) etc. devices push the communication technology towards the D-Band spectrum which is the wide available spectrum centred at 140 GHz [1]. Therefore, D-Band will become a milestone for 5G and Beyond 5G Cellular Networks in the future. Mixers are a frequency translation element extensively employed in wireless transceivers to shift the information from a lower frequency signal to a higher frequency one and vice versa. On the transmitter side, they are generally placed before the power amplifier which drives the antenna. However, mixers usually lack of output power and power amplifiers need to be designed with the required gain to achieve the desired power saturation level. In this thesis, a novel concept of an up-conversion power mixer is presented. A power mixer with more than 10 dBm of output power will relax the design constraints on the following power amplifier resulting in a big advantage on the final transceiver design. This M.Sc. thesis activity covers possible challenges in the design of an up- conversion power mixer in D-Band. Several mixer topologies are explored and advantages and disadvantages of each of them are highlighted. The design of a topology known as Active Double Balanced Mixer topology is presented. This design is implemented by means of a Current Driven Common-Base Mixer, where a passive transconductance stage feeds a Gilbert-Cell stage and a cascode stage is used to boost the output impedance in order to provide the required power at the output. Finally, current- clamping technique is employed to improve efficiency in back-off.