A Millimeter-Wave Coexistent RFIC Receiver Architecture in 0.18-µm SiGe BiCMOS for Radar and Communication Systems

Innovative circuit architectures and techniques to enhance the performance of several key BiCMOS RFIC building blocks applied in radar and wireless communication systems operating at the millimeter-wave frequencies are addressed in this dissertation. The former encapsulates the development of an advanced, low-cost and miniature millimeter-wave coexistent current mode direct conversion receiver for short-range, high-resolution radar and high data rate communication systems. A new class of broadband low power consumption active balun-LNA consisting of two common emitters amplifiers mutually coupled thru an AC stacked transformer for power saving and gain boosting. The active balun-LNA exhibits new high linearity technique using a constant gm cell transconductance independent of input-outputs variations based on equal emitters’ area ratios. A novel multi-stages active balun-LNA with innovative technique to mitigate amplitude and phase imbalances is proposed. The new multi-stages balun-LNA technique consists of distributed feed-forward averaging recycles correction for amplitude and phase errors and is insensitive to unequal paths parasitic from input to outputs. The distributed averaging recycles correction technique resolves the amplitude and phase errors residuals in a multi-iterative process. The new multi-stages balun-LNA averaging correction technique is frequency independent and can perform amplitude and phase calibrations without relying on passive lumped elements for compensation. The multi-stage balun-LNA exhibits excellent performance from 10 to 50 GHz with amplitude and phase mismatches less than 0.7 dB and 2.86º, respectively. Furthermore, the new multi-stages balun-LNA operates in current mode and shows high linearity with low power consumption. The unique balun-LNA design can operates well into mm-wave regions and is an integral block of the mm-wave radar and communication systems. The integration of several RFIC blocks constitutes the broadband millimeter-wave coexistent current mode direct conversion receiver architecture operating from 22- 44 GHz. The system and architectural level analysis provide a unique understanding into the receiver characteristics and design trade-offs. The RF front-end is based on the broadband multi-stages active balun-LNA coupled into a fully balanced passive mixer with an all-pass in-phase/quadrature phase generator. The trans-impedance amplifier converts the input signal current into a voltage gain at the outputs. Simultaneously, the high power input signal current is channelized into an anti-aliasing filter with 20 dB rejection for out of band interferers. In addition, the dissertation demonstrates a wide dynamic range system with small die area, cost effective and very low power consumption

A Millimeter-Wave Coexistent RFIC Receiver Architecture in 0.18-µm SiGe BiCMOS for Radar and Communication Systems

Innovative circuit architectures and techniques to enhance the performance of several key BiCMOS RFIC building blocks applied in radar and wireless communication systems operating at the millimeter-wave frequencies are addressed in this dissertation. The former encapsulates the development of an advanced, low-cost and miniature millimeter-wave coexistent current mode direct conversion receiver for short-range, high-resolution radar and high data rate communication systems. A new class of broadband low power consumption active balun-LNA consisting of two common emitters amplifiers mutually coupled thru an AC stacked transformer for power saving and gain boosting. The active balun-LNA exhibits new high linearity technique using a constant gm cell transconductance independent of input-outputs variations based on equal emitters’ area ratios. A novel multi-stages active balun-LNA with innovative technique to mitigate amplitude and phase imbalances is proposed. The new multi-stages balun-LNA technique consists of distributed feed-forward averaging recycles correction for amplitude and phase errors and is insensitive to unequal paths parasitic from input to outputs. The distributed averaging recycles correction technique resolves the amplitude and phase errors residuals in a multi-iterative process. The new multi-stages balun-LNA averaging correction technique is frequency independent and can perform amplitude and phase calibrations without relying on passive lumped elements for compensation. The multi-stage balun-LNA exhibits excellent performance from 10 to 50 GHz with amplitude and phase mismatches less than 0.7 dB and 2.86º, respectively. Furthermore, the new multi-stages balun-LNA operates in current mode and shows high linearity with low power consumption. The unique balun-LNA design can operates well into mm-wave regions and is an integral block of the mm-wave radar and communication systems. The integration of several RFIC blocks constitutes the broadband millimeter-wave coexistent current mode direct conversion receiver architecture operating from 22- 44 GHz. The system and architectural level analysis provide a unique understanding into the receiver characteristics and design trade-offs. The RF front-end is based on the broadband multi-stages active balun-LNA coupled into a fully balanced passive mixer with an all-pass in-phase/quadrature phase generator. The trans-impedance amplifier converts the input signal current into a voltage gain at the outputs. Simultaneously, the high power input signal current is channelized into an anti-aliasing filter with 20 dB rejection for out of band interferers. In addition, the dissertation demonstrates a wide dynamic range system with small die area, cost effective and very low power consumption

Ultra high data rate CMOS front ends

The availability of numerous mm-wave frequency bands for wireless communication has motivated the exploration of multi-band and multi-mode integrated components and systems in the main stream CMOS technology. This opportunity has faced the RF designer with the transition between schematic and layout. Modeling the performance of circuits after layout and taking into account the parasitic effects resulting from the layout are two issues that are more important and influential at high frequency design. Performing measurements using on-wafer probing at 60 GHz has its own complexities. The very short wave-length of the signals at mm-wave frequencies makes the measurements very sensitive to the effective length and bending of the interfaces. This paper presents different 60 GHz corner blocks, e.g. Low Noise Amplifier, Zero IF mixer, Phase-Locked Loop, a Dual-Mode Mm-Wave Injection-Locked Frequency Divider and an active transformed power amplifiers implemented in CMOS technologies. These results emphasize the feasibility of the realization 60 GHZ integrated components and systems in the main stream CMOS technology

Digitally tunable low noise amplifier

Low noise amplifiers are classified into two categories: Wideband low noise amplifiers and Narrowband low noise amplifiers. Wideband LNAs are known for achieving a poor noise performance. On the other hand, the noise performance of the narrowband amplifiers is good but only over a small frequency range. This constraint made their use restricted to certain applications, such as cellular phone applications (superheterodyne architecture), where a single operational frequency is needed. This thesis introduces a new low noise amplifier topology that provides a high selectivity and a low noise figure over a wide frequency range. The digitally tunable low noise amplifier can be implemented in narrowband applications as well as broadband applications. This thesis discusses in detail the design of the DTLNA. A detailed noise analysis is also discussed in this work. The noise analysis includes the effect of induced gate noise in CMOS, which is rarely cited but nonetheless of fundamental importance in establishing the limits of achievable noise performance. In addition, this thesis demonstrates the performance results of the digitally tunable low noise amplifier. These results prove that the overall performance of the DTLNA surpasses the performance of both wideband and narrowband amplifiers

A 39GHz Balanced Power Amplifier with Enhanced Linearity in 45 nm SOI CMOS

With the high data rate communication systems that come with fifth-generation (5G) mobile networks, the shift of operation to millimeter-wave frequency becomes inevitable. The expected data rate in 5G is significantly improved over 4G by utilizing the large available channel bandwidth at millimeter wave frequencies and complex data modulation schemes. With this increase in operation frequency, many new challenges arise and research efforts are made to tackle them. Among them, the phased array system is one of the hottest topics as it can be made use of to improve the link budget and overcome the path loss challenge at these frequencies. As the last circuit component in the transmitter's front-end right before the antenna, the power amplifier (PA) is one of the most crucial components with significant effects on overall system performance. Many of the traditional challenges of CMOS PA design such as output power and efficiency, are now compounded with the additional challenges that are imposed on complementary metal-oxide semiconductor (CMOS) PAs in millimeter wave phased array systems. This thesis presents a balanced power amplifier design with enhanced linearity in GlobalFoundries' 45nm silicon-on-insulator (SOI) CMOS technology. By using the balanced topology with each stage terminating with a differential 2-stacked architecture, the PA achieves saturated output power of over 21 dBm. Each of the two identical sub-PAs in the balanced topology uses 2-stage topology with driver and PA co-design method. The linearity is enhanced through careful choice of biasing point and a strategic inter-stage matching network design methodology, resulting in amplitude-to-phase distortion below 1 degree up to the output 1dB compression level of over 19 dBm. The balanced amplifier topology significantly reduces the PA performance variation over mismatched load impedance at the output, thus improving the PA performance over different antenna active impedance caused by varying phased array beam-steering angles. In addition to this, the balanced topology also optimizes the PA input and output return loss, giving a better matching than -20 dB at both input and output, and minimizing the risk of potential issues and performance degradation in the system integration phase. Lastly, the compact transformer based matching networks and quadrature hybrids reduce the chip area occupation of this PA, resulting in a compact design with competitive performance

ANALYSIS AND DESIGN OF SILICON-BASED MILLIMETER-WAVE AMPLIFIERS

Ph.DDOCTOR OF PHILOSOPH

Efficient and Linear CMOS Power Amplifier and Front-end Design for Broadband Fully-Integrated 28-GHz 5G Phased Arrays

Demand for data traffic on mobile networks is growing exponentially with time and on a global scale. The emerging fifth-generation (5G) wireless standard is being developed with millimeter-wave (mm-Wave) links as a key technological enabler to address this growth by a 2020 time frame. The wireless industry is currently racing to deploy mm-Wave mobile services, especially in the 28-GHz band. Previous widely-held perceptions of fundamental propagation limitations were overcome using phased arrays. Equally important for success of 5G is the development of low-power, broadband user equipment (UE) radios in commercial-grade technologies. This dissertation demonstrates design methodologies and circuit techniques to tackle the critical challenge of key phased array front-end circuits in low-cost complementary metal oxide semiconductor (CMOS) technology. Two power amplifier (PA) proof-of-concept prototypes are implemented in deeply scaled 28- nm and 40-nm CMOS processes, demonstrating state-of-the-art linearity and efficiency for extremely broadband communication signals. Subsequently, the 40 nm PA design is successfully embedded into a low-power fully-integrated transmit-receive front-end module. The 28 nm PA prototype in this dissertation is the first reported linear, bulk CMOS PA targeting low-power 5G mobile UE integrated phased array transceivers. An optimization methodology is presented to maximizing power added efficiency (PAE) in the PA output stage at a desired error vector magnitude (EVM) and range to address challenging 5G uplink requirements. Then, a source degeneration inductor in the optimized output stage is shown to further enable its embedding into a two-stage transformer-coupled PA. The inductor helps by broadening inter-stage impedance matching bandwidth, and helping to reduce distortion. Designed and fabricated in 1P7M 28 nm bulk CMOS and using a 1 V supply, the PA achieves +4.2 dBm/9% measured Pout/PAE at −25 dBc EVM for a 250 MHz-wide, 64-QAM orthogonal frequency division multiplexing (OFDM) signal with 9.6 dB peak-to-average power ratio (PAPR). The PA also achieves 35.5%/10% PAE for continuous wave signals at saturation/9.6dB back-off from saturation. To the best of the author’s knowledge, these are the highest measured PAE values among published K- and K a-band CMOS PAs to date. To drastically extend the communication bandwidth in 28 GHz-band UE devices, and to explore the potential of CMOS technology for more demanding access point (AP) devices, the second PA is demonstrated in a 40 nm process. This design supports a signal radio frequency bandwidth (RFBW) >3× the state-of-the-art without degrading output power (i.e. range), PAE (i.e. battery life), or EVM (i.e. amplifier fidelity). The three-stage PA uses higher-order, dual-resonance transformer matching networks with bandwidths optimized for wideband linearity. Digital gain control of 9 dB range is integrated for phased array operation. The gain control is a needed functionality, but it is largely absent from reported high-performance mm-Wave PAs in the literature. The PA is fabricated in a 1P6M 40 nm CMOS LP technology with 1.1 V supply, and achieves Pout/PAE of +6.7 dBm/11% for an 8×100 MHz carrier aggregation 64-QAM OFDM signal with 9.7 dB PAPR. This PA therefore is the first to demonstrate the viability of CMOS technology to address even the very challenging 5G AP/downlink signal bandwidth requirement. Finally, leveraging the developed PA design methodologies and circuits, a low power transmit-receive phased array front-end module is fully integrated in 40 nm technology. In transmit-mode, the front-end maintains the excellent performance of the 40 nm PA: achieving +5.5 dBm/9% for the same 8×100 MHz carrier aggregation signal above. In receive-mode, a 5.5 dB noise figure (NF) and a minimum third-order input intercept point (IIP₃) of −13 dBm are achieved. The performance of the implemented CMOS frontend is comparable to state-of-the-art publications and commercial products that were very recently developed in silicon germanium (SiGe) technologies for 5G communication

Analysis and design of a high power millimeter-wave power amplifier in a SiGe BiCMOS technology

Our current society is characterized by an ever increasing need for bandwidth leading towards the exploration of new parts of the electromagnetic spectrum for data transmission. This results in a rising interest and development of millimeter-wave (mm-wave) circuits which hold the promise of short range multi-gigabit wireless transmissions at 60GHz. These relatively new applications are to co-exist with more established mm-wave consumer products including satellite systems in the Ka-band (26.5GHz - 40GHz) allowing e.g.: video broadcasting, voice over IP (VoIP), internet acces to remote areas, ... Both need significant linear power amplification due to the high attenuation typical for this part of the spectrum, however, satellite systems demand a saturated output power which is easily an order of magnitude larger (output powers in excess of 30dBm / 1W). Monolithic microwave integrated circuits (MMICs) employing III-V chip technologies, e.g.: gallium arsenide (GaAs), gallium nitride (GaN), have historically been the preferred choice to implement efficient mm-wave power amplifiers (PA) with a high saturated output power (>30dBm). To further increase the commercial viability of consumer products in this market segment a low manufacturing cost for the power amplifier, together with the possible integration of additional functions, is highly desirable. These features are the strongpoint of silicon based chip technologies like CMOS and SiGe BiCMOS. However, these technologies have a breakdown voltage typically below 2V for nodes capable of millimeter-wave applications while III-V transistors with equivalent frequency performance demonstrate breakdown voltages in excess of 8V. Because of this, output powers of CMOS and SiGe BiCMOS Ka-band power amplifiers rarely exceed 20dBm which poses the main hurdle for using these technologies in satellite communication (SATCOM). To overcome the limited output power of a single amplifying cell in a silicon technology, caused by the low breakdown voltage, multiple power amplifiers cells need to have their output power effectively combined on-chip. This requires the on-chip integration of high-Q passives within a relative small area to realize both the impedance transformation, to create the optimal load impedance for the different amplifier cells, and implement an efficient on-chip power combination network. Compared to III-V technologies this is again a challenge due to the use of a silicon substrate which introduces higher losses. Once a large enough on-chip output power is created, the issue of launching this signal to the outside world remains. Moreover, due to the limited efficiency of mm-wave PAs, the generated on-chip heat will increase when larger output power are required. This means a chipto-board interface with a low thermal resistance and a low loss electrical connection needs to be devised. Proof of the viability of silicon as a serious candidate for the integration of medium and high power Ka-band amplifiers will only be delivered by long term research and the actual creation of such an amplifier. In this context, the initial goal for the presented work is proposed. This consists of the creation of a power amplifier with a saturated output power above 24dBm (preferably 27dBm), a gain larger than 20dB and an efficiency in excess of 10% (preferably 15%). These specifications where conceived with the precondition of using a 250nm SiGe BiCMOS technology (IHP’s SG25H3) with an fT of 110GHz and a collector to emitter breakdown voltage in open base conditions (BVCEO) of 2.3V. The use of this technology is a significant challenge due to the limited speed, rule of thumb is to have at least one fifth of the fT as the operating frequency, which reflects in the attainable power added efficiency (PAE). On the other hand, proving the possible implementation in this “older” technology shows great potential towards the future integration in a fast technology (e.g.: IHP’s SG13G2, ft =300GHz). Next to issues caused by limitations of the chip technology, the proposed specifications allows to identify generic difficulties with high power silicon PA design, e.g.: design of efficient on-chip power combiners, thermal management, single-ended to differential conversion, ... As this work is of an academic nature the intention of this design was to leave the beaten track and explore alternative topologies. This has led to the adoption of a driver stage using translinear loops for biasing and a transformer-type Wilkinson power combiner previously only used in cable television (CATV) applications. Although the power combiner showed 2dB more loss than expected due to higher than expected substrate losses, both topologies show promise for further integration. Furthermore, an in-depth analysis was performed on the output stage which uses positive feedback to increase its gain. The entire design consists of a four-way power combining class AB power amplifier together with test structures of which the performance was verified by means of probing. Due to the previously mentioned higher than expected loss in the on-chip power combiner, the total output power and power added efficiency (PAE) was 2dB lower than expected from simulations. The result is a saturated output power at 32GHz of 24.1dBm with a PAE of 7.2% and a small signal gain of 25dB. This demonstrates the capability of SiGe BiCMOS to implement PA’s for medium-power mm-wave applications. Moreover, to the best of the author’s knowledge, this PA achieves the second highest saturated output power when comparing SiGe BiCMOS PA’s with center frequency in or close to the Ka-band. The 1dB compression point of this amplifier lies at 22.7dBm which is close to saturated output power and results in a low spectral regrowth when compared to commercial GaAs PA’s (compared with 2MBaud 16QAM input signal at 10dB back-off). Many possible improvements to this design remain. The most important would be the re-design of the on-chip power combiner, possibly with a floating ground shield, to reduce the losses and increase the total output power and PAE. Also the porting of the design to a faster chip technology might result in a considerable increase of the output stage efficiency at the cost of needing to combine more amplifier cells. The transition to a faster chip technology would additionally allow to use this design for alternative mm-wave applications like automotive radar at 79GHz andWiGig at 60GHz

Design of 28 GHz Low-Power Phased-Array Receiver Frontend in CMOS

This work presents the design and implementation of a low power phased-array receiver frontend at 28 GHz in 65 nm CMOS. The frontend incorporates a low- power low-noise amplifier(LNA) and a passive reflection-type phase shifter (RTPS) capable of providing 360° phase shift with 5-bit phase resolution and low loss variation. Passive phase-shifters in the literature suffer from trade-offs between finite phase resolution, insertion loss and phase shift range, and hence do not provide 360° phase range with uniform, low loss across phase shift settings. The proposed systematic design and load optimization approach leads to the RTPS achieving state-of-art performance in terms of insertion loss with 360° phase shift range, loss variation across phase shift and rms phase error. The low-power LNA is based on a transformer-coupled neutralization architecture that increases gain in each LNA stage, allowing for lower power consumption. The phased-array frontend is designed for Ka-band applications and has been characterized in 65nm CMOS from 26 GHz -30 GHz. The measured RTPS achieves 360 degrees phase shift with -7.75+/-0.3 dB and rms phase error of 0.3 degrees at 28 GHz. The low power phased-array receiver frontend has overall gain of 9.5 dB, gain variation of +/-0.4 dB and measured noise figure of 4.9 dB at 28 GHz. The receiver frontend consumes 10 mW from a 0.9 V supply with phase shifter and LNA active area of 0.16 mm² and 0.32 mm² respectively in 65nm CMOS, demonstrating its suitability for integration into low-power phased array receivers for emerging high data rate 5G wireless communication applications at 28 GHz