This Is AuburnElectronic Theses and Dissertations

Design and Implementation of RF Receiver Front-end and Tunable Filter




Ma, Desheng

Type of Degree



Electrical Engineering


In this work, several novel topologies for RF receivers, like reconfigurable wideband low noise amplifier (LNA), mixers with gain reuse, high resolution digitally controlled oscillator and the low power wideband receiver are investigated. The work uses both standard silicon CMOS and SiGe BiCMOS technology to demonstrate operations of those building blocks and the whole receiver. First, a LNA MMIC with notch filter implemented in a 0.13um SiGe BiCMOS technology is introduced. The LNA utilizes Q-enhanced techniques to achieve high gain and high image rejection ratio (IRR) simultaneously. With Q-enhanced techniques, 70dB image rejection ratio is achieved in the LNA. Next, the design of a wide-band LNA for self-healing application is demonstrated. With the self-healing technology, the peak gain frequency and the input matching frequency can be adjusted to the operating frequency simultaneously. Meanwhile, the gain of proposed LNA is also adjustable for self-healing purpose. In order to implement a digital phase locked loop (DPLL), a 12 bits digitally controlled oscillator implemented in 0.18um CMOS technology is also investigated in the following chapter. After introducing the building blocks, this dissertation presents an 8-18GHz wideband receiver with super-heterodyne topology. Multi-feedback technology, which provides more freedom in input matching, was utilized in the LNA design for the input matching over the X- and Ku-band frequency range. In order to save power, both the RF and IF signals share the tunable transconductance stage. The IF output of the first mixer is fed back into the tunable input stage for IF amplification in a recursive manner, which significantly enhances the gain tuning without increasing the power. In the second part of the dissertation, tunable filter technologies are discussed. Two different tunable filter architectures are discussed and implemented. One is the 6th order Butterworth switched capacitor (SC) low pass filter while another is low pass filter based on the tunable active CMOS resistor. The SC filter is capable of operating over an ultra-wide temperature (UWT) range from -180ºC to 120ºC and under high-energy particle radiation environment on the lunar surface. The later tunable filter is based on a novel tunable CMOS resistor. The resistance is inversely proportional to bias current, to provide the resistor with a wider tuning range. And transistors, which compose the active resistor, operate at saturation region to achieve very large resistance within a small area.