| In recent years, there has been a substantial increase in the development of broadband wireless access technologies for evolving wireless mobile Internet services and next-generation cellular systems. The surge in wireless networking is driven by its promise of easily deployable, low-cost solutions.; Adaptive arrays can provide a promising solution while achieving reliable and robust high-speed high data-rate transmission. The quality of speech and data transmission in a cellular network is determined by the SNR and CIR. Several major mobile phone manufactures are presently doing intensive research in smart antenna systems for handsets as a method for improving both SNR and CIR level.; Variable phase shifters are used in many applications such as multiple-adaptive antenna receiver. Basically, each receiver implements a complex gain function with a variable low noise amplifier and a phase shifter controlled by the channel estimation block so as to maximize the overall receiver SNR. Hence, precision low-cost phase shifting circuits are a critical component of future wireless devices.; The requirement for the phase shifter is 360° phase shift range, high phase shift resolution, gain, and linearity, linear phase shift versus control voltage, low power dissipation, low NF, and compact size. Design a phase shifter with these requirements are a very difficult job, needs to find a new structure to implement in silicon process.; This thesis used several techniques to overcome these issues. First a passive topology is chosen due to have high linearity, and zero power consumption. An active negative resistance function is added to a passive phase shifter to reduce signal losses. Since losses are decreased, the potential noise added by the active devices is mitigated and the NF is also improved.; A replica technique is used to provide insensitivity to process-voltage-temperature variations and to have the possibility of control the phase shift and gain variation of the phase shifter, with a sigma-delta PLL and amplitude-locked-loop, respectively. This also creates a simpler means of phase control than has been used previously and this also reduces the cost of the phase shifting network. Finally another proposed impedance arrangement provides full range phase shift with low signal loss. |
