Mixed Linearity Improvement Techniques for Ultra-wideband Low Noise Amplifier

We present the linearization of an ultra-wideband low noise amplifier (UWB-LNA) operating from 2GHz to 11GHz through combining two linearization methods. The used linearization techniques are the combination of post-distortion cancellation and derivative-superposition linearization methods. The linearized UWB-LNA shows an improved linearity (IIP3) of +12dBm, a minimum noise figure (NFmin.) of 3.6dB, input and output insertion losses (S11 and S22)  below -9dB over the entire working bandwidth, midband gain of 6dB at 5.8GHz, and overall circuit power consumption of 24mW supplied from a 1.5V voltage source. Both UWB-LNA and linearized UWB-LNA designs are verified and simulated with ADS2016.01 software using BSIM3v3 TSMC 180nm CMOS model files. In addition, the linearized UWB-LNA performance is compared with other recent state-of-the-art LNAs

Linearity vs. Power Consumption of CMOS LNAs in LTE Systems

This paper presents a study of linearity in wideband CMOS low noise amplifiers (LNA) and its relationship to power consumption in context of Long Term Evolution (LTE) system. Using proposed figure of merit to compare 35 state-of-the-art LNA circuits published in recent years, the paper shows a proportional but relatively weak dependence between amplifier performance (that is combined linearity, noise figure and gain) with power consumption. As a result, the predicted increase of LNA performance, necessary to satisfy stringent linearity specifications of LTE standard, may require a significant increase in power, a critical budget planning aspect for both handheld devices and base stations operating in small cells

RF Amplification and Filtering Techniques for Cellular Receivers

The usage of various wireless standards, such as Bluetooth, Wi-Fi, GPS, and 4G/5G cellular, has been continually increasing. In order to utilize the frequency bands efficiently and to support new communication standards with lower power consumption, lower occupied volume and at reduced costs, multimode transceivers, software defined radios (SDRs), cognitive radios, etc., have been actively investigated. Broadband behavior of a wireless receiver is typically defined by its front-end low-noise amplifier (LNA), whose design must consider trade-offs between input matching, noise figure (NF), gain, bandwidth, linearity, and voltage headroom in a given process technology. Moreover, monolithic RF wireless receivers have been trending toward high intermediatefrequency (IF) or superhetrodyne radios thanks to recent breakthroughs in silicon integration of band-pass channel-select filters. The main motivation is to avoid the common issues in the currently predominant zero/low-IF receivers, such as poor 2nd-order nonlinearity, sensitivity to 1/f (i.e. flicker) noise and time-variant dc offsets, especially in the fine CMOS technology. To avoid interferers and blockers at the susceptible image frequencies that the high-IF entails, band-pass filters (BPF) with high quality (Q) factor components for sharp transfer-function transition characteristics are now required. In addition, integrated low-pass filters (LPF) with strong rejection of out-of-band frequency components are essential building blocks in a variety of applications, such as telecommunications, video signal processing, anti-aliasing filtering, etc. Attention is drawn toward structures featuring low noise, small area, high in-/out-of-band linearity performance, and low-power consumption. This thesis comprises three main parts. In the first part (Chapters 2 and 3), we focus on the design and implementation of several innovative wideband low-noise (transconductance) amplifiers [LN(T)A] for wireless cellular applications. In the first design, we introduce new approaches to reduce the noise figure of the noise-cancellation LNAs without sacrificing the power consumption budget, which leads to NF of 2 dB without adding extra power consumption. The proposed LNAs also have the capability to be used in current-mode receivers, especially in discrete-time receivers, as in the form of low noise transconductance amplifier (LNTA). In the second design, two different two-fold noise cancellation approaches are proposed, which not only improve the noise performance of the design, but also achieve high linearity (IIP3=+4.25 dBm). The proposed LN(T)As are implemented in TSMC 28-nm LP CMOS technology to prove that they are suitable for applications such as sub-6 GHz 5G receivers. The second objective of this dissertation research is to invent a novel method of band-pass filtering, which leads to achieving very sharp and selective band-pass filtering with high linearity and low input referred (IRN) noise (Chapter 4). This technique improves the noise and linearity performance without adding extra clock phases. Hence, the duty cycle of the clock phases stays constant, despite the sophisticated improvements. Moreover, due to its sharp filtering, it can filter out high blockers of near channels and can increase the receiver’s blocker tolerance. With the same total capacitor size and clock duty cycle as in a 1st-order complex charge-sharing band-pass filter (CS BPF), the proposed design achieves 20 dB better out-of-band filtering compared to the prior-art 1st-order CS BPF and 10 dB better out-of-band filtering compared to the conventional 2nd-order C-CS BPF. Finally, the stop-band rejection of the discrete-time infinite-impulse response (IIR) lowpass filter is improved by applying a novel technique to enhance the anti-aliasing filtering (Chapter 5). The aim is to introduce a 4th-order charge rotating (CR) discrete-time (DT) LPF, which achieves the record of stop-band rejection of 120 dB by using a novel pseudolinear interpolation technique while keeping the sampling frequency and the capacitor values constant

Ultra-Low Power Transmitter and Power Management for Internet-of-Things Devices

Two of the most critical components in an Internet-of-Things (IoT) sensing and transmitting node are the power management unit (PMU) and the wireless transmitter (Tx). The desire for longer intervals between battery replacements or a completely self-contained, battery-less operation via energy harvesting transducers and circuits in IoT nodes demands highly efficient integrated circuits. This dissertation addresses the challenge of designing and implementing power management and Tx circuits with ultra-low power consumption to enable such efficient operation. The first part of the dissertation focuses on the study and design of power management circuits for IoT nodes. This opening portion elaborates on two different areas of the power management field: Firstly, a low-complexity, SPICE-based model for general low dropout (LDO) regulators is demonstrated. The model aims to reduce the stress and computation times in the final stages of simulation and verification of Systems-on-Chip (SoC), including IoT nodes, that employ large numbers of LDOs. Secondly, the implementation of an efficient PMU for an energy harvesting system based on a thermoelectric generator transducer is discussed. The PMU includes a first-in-its-class LDO with programmable supply noise rejection for localized improvement in the suppression. The second part of the dissertation addresses the challenge of designing an ultra- low power wireless FSK Tx in the 900 MHz ISM band. To reduce the power consumption and boost the Tx energy efficiency, a novel delay cell exploiting current reuse is used in a ring-oscillator employed as the local oscillator generator scheme. In combination with an edge-combiner PA, the Tx showed a measured energy efficiency of 0.2 nJ/bit and a normalized energy efficiency of 3.1 nJ/(bit∙mW) when operating at output power levels up to -10 dBm and data rates of 3 Mbps. To close this dissertation, the implementation of a supply-noise tolerant BiCMOS ring-oscillator is discussed. The combination of a passive, high-pass feedforward path from the supply to critical nodes in the selected delay cell and a low cost LDO allow the oscillator to exhibit power supply noise rejection levels better than –33 dB in experimental results