Millimeter-wave Communication and Radar Sensing — Opportunities, Challenges, and Solutions

With the development of communication and radar sensing technology, people are able to seek for a more convenient life and better experiences. The fifth generation (5G) mobile network provides high speed communication and internet services with a data rate up to several gigabit per second (Gbps). In addition, 5G offers great opportunities of emerging applications, for example, manufacture automation with the help of precise wireless sensing. For future communication and sensing systems, increasing capacity and accuracy is desired, which can be realized at millimeter-wave spectrum from 30 GHz to 300 GHz with several tens of GHz available bandwidth. Wavelength reduces at higher frequency, this implies more compact transceivers and antennas, and high sensing accuracy and imaging resolution. Challenges arise with these application opportunities when it comes to realizing prototype or demonstrators in practice. This thesis proposes some of the solutions addressing such challenges in a laboratory environment.High data rate millimeter-wave transmission experiments have been demonstrated with the help of advanced instrumentations. These demonstrations show the potential of transceiver chipsets. On the other hand, the real-time communication demonstrations are limited to either low modulation order signals or low symbol rate transmissions. The reason for that is the lack of commercially available high-speed analog-to-digital converters (ADCs); therefore, conventional digital synchronization methods are difficult to implement in real-time systems at very high data rates. In this thesis, two synchronous baseband receivers are proposed with carrier recovery subsystems which only require low-speed ADCs [A][B].Besides synchronization, high-frequency signal generation is also a challenge in millimeter-wave communications. The frequency divider is a critical component of a millimeter-wave frequency synthesizer. Having both wide locking range and high working frequencies is a challenge. In this thesis, a tunable delay gated ring oscillator topology is proposed for dual-mode operation and bandwidth extension [C]. Millimeter-wave radar offers advantages for high accuracy sensing. Traditional millimeter-wave radar with frequency-modulated continuous-wave (FMCW), or continuous-wave (CW), all have their disadvantages. Typically, the FMCW radar cannot share the spectrum with other FMCW radars.\ua0 With limited bandwidth, the number of FMCW radars that could coexist in the same area is limited. CW radars have a limited ambiguous distance of a wavelength. In this thesis, a phase-modulated radar with micrometer accuracy is presented [D]. It is applicable in a multi-radar scenario without occupying more bandwidth, and its ambiguous distance is also much larger than the CW radar. Orthogonal frequency-division multiplexing (OFDM) radar has similar properties. However, its traditional fast calculation method, fast Fourier transform (FFT), limits its measurement accuracy. In this thesis, an accuracy enhancement technique is introduced to increase the measurement accuracy up to the micrometer level [E]

Frequency Synthesizers and Oscillator Architectures Based on Multi-Order Harmonic Generation

Frequency synthesizers are essential components for modern wireless and wireline communication systems as they provide the local oscillator signal required to transmit and receive data at very high rates. They are also vital for computing devices and microcontrollers as they generate the clocks required to run all the digital circuitry responsible for the high speed computations. Data rates and clocking speeds are continuously increasing to accommodate for the ever growing demand on data and computational power. This places stringent requirements on the performance metrics of frequency synthesizers. They are required to run at higher speeds, cover a wide range of frequencies, provide a low jitter/phase noise output and consume minimum power and area. In this work, we present new techniques and architectures for implementing high speed frequency synthesizers which fulfill the aforementioned requirements. We propose a new architecture and design approach for the realization of wideband millimeter-wave frequency synthesizers. This architecture uses two-step multi-order harmonic generation of a low frequency phase-locked signal to generate wideband mm-wave frequencies. A prototype of the proposed system is designed and fabricated in 90nm Complementary Metal Oxide Semiconductor (CMOS) technology. Measurement results demonstrated that a very wide tuning range of 5 to 32 GHz can be achieved, which is costly to implement using conventional techniques. Moreover the power consumption per octave resembles that of state-of-the art reports. Next, we propose the N-Push cyclic coupled ring oscillator (CCRO) architecture to implement two high performance oscillators: (1) a wideband N-Push/M-Push CCRO operating from 3.16-12.8GHz implemented by two harmonic generation operations using the availability of different phases from the CCRO, and (2) a 13-25GHz millimeter-wave N-Push CCRO with a low phase noise performance of -118dBc/Hz at 10MHz. The proposed oscillators achieve low phase noise with higher FOM than state of the art work. Finally, we present some improvement techniques applied to the performance of phase locked loops (PLLs). We present an adaptive low pass filtering technique which can reduce the reference spur of integer-N charge-pump based PLLs by around 20dB while maintaining the settling time of the original PLL. Another PLL is presented, which features very low power consumption targeting the Medical Implantable Communication Standard. It operates at 402-405 MHz while consuming 600microW from a 1V supply

Novel RF CMOS Integrated Circuits and Systems for Broadband Dielectric Spectroscopy

Broadband dielectric spectroscopy has proven to be a valuable technique for characterization of chemicals and biomaterials. It has the great potential to become an indispensable and cost-effective tool in point-of-care medical applications due to its label-free and non-invasive operation. However, most of the existing dielectric spectroscopy instruments require bulky, heavy and expensive measurement set-up, restricting their use to only special applications in industry and laboratories. Therefore, integrated dielectric spectroscopy on silicon capable of direct detection of chemicals/biomaterials' complex permittivity can yield significant cost and size reduction, system integration, portability, enormous processing, and high throughput. A CMOS wideband dielectric spectroscopy system is proposed for chemical and biological material characterization. The complex permittivity detection is performed using a configurable harmonic-rejecting receiver capable of indirectly measuring the complex admittance of sensing capacitor exposed to the material-under-test (MUT) and subject to RF signal excitation with a frequency range of 0.62-10 GHz. The sensing capacitor is embedded in a voltage divider topology with a fixed capacitor and the relative variations in the magnitude and phase of the voltages across the capacitors are used to find the real and imaginary parts of the permittivity. The sensor achieves an rms permittivity error of less than 1% over the entire operation bandwidth. Using a sub-harmonic mixing scheme, the system can perform complex permittivity measurements from 0.62 to 10 GHz while requiring an input signal source with frequency range of only from 5 to 10 GHz. Thereby, the permittivity measurement system can be easily made self-sustained by implementing a 5-10 GHz frequency synthesizer on the same chip. One of the key building blocks in such a frequency synthesizer is the voltage-controlled oscillator (VCO) which has to cover an octave of frequency range. A novel low-phase-noise wide-tuning range VCO is presented using a triple-band LC resonator. The implemented VCO in 0.18μm CMOS technology achieves a continuous tuning range of 86.7% from 5.12 GHz to 12.95 GHz while drawing 5 to 10 mA current from 1-V supply. The measured phase noise at 1 MHz offset from carrier frequencies of 5.9, 9.12 and 12.25 GHz is -122.9, -117.1 and -110.5 dBc/Hz, respectively. Also, a dual-band quadrature voltage-controlled oscillator (QVCO) is presented using a transformer-based high-order LC-ring resonator which inherently provides quadrature signals without requiring noisy coupling transistors as in traditional approaches. The proposed resonator shows two possible oscillation frequencies which are exploited to realize a wide-tuning range QVCO employing a mode-switching transistor network. Due to the use of transformers, the oscillator has minimal area penalty compared to the conventional designs. The implemented prototype in a 65-nm CMOS process achieves a continuous tuning range of 77.8% from 2.75 GHz to 6.25 GHz while consuming 9.7 to 15.6 mA current from 0.6-V supply. The measured phase noise figure-of-merit (FoM) at 1 MHz offset ranges from 184 dB to 188.2 dB throughout the entire tuning range. The QVCO also exhibits good quadrature accuracy with 1.5º maximum phase error and occupies a relatively small silicon area of 0.35 mm^2

Millimeter-scale RF Integrated Circuits and Antennas for Energy-efficient Wireless Sensor Nodes

Recently there has been increased demand for a millimeter-scale wireless sensor node for applications such as biomedical devices, defense, and surveillance. This form-factor is driven by a desire to be vanishingly small, injectable through a needle, or implantable through a minimally-invasive surgical procedure. Wireless communication is a necessity, but there are several challenges at the millimeter-scale wireless sensor node. One of the main challenges is external components like crystal reference and antenna become the bottleneck of realizing the mm-scale wireless sensor node device. A second challenge is power consumption of the electronics. At mm-scale, the micro-battery has limited capacity and small peak current. Moreover, the RF front-end circuits that operates at the highest frequency in the system will consume most of the power from the battery. Finally, as node volume reduces, there is a challenge of integrating the entire system together, in particular for the RF performance, because all components, including the battery and ICs, need to be placed in close proximity of the antenna. This research explores ways to implement low-power integrated circuits in an energy-constrained and volume constrained application. Three different prototypes are mainly conducted in the proposal. The first is a fully-encapsulated, autonomous, complete wireless sensor node with UWB transmitter in 10.6mm3 volume. It is the first time to demonstrate a full and stand-alone wireless sensing functionality with such a tiny integrated system. The second prototype is a low power GPS front-end receiver that supports burst-mode. A double super-heterodyne topology enables the reception of the three public GPS bands, L1, L2 and L5 simultaneously. The third prototype is an integrated rectangular slot loop antenna in a standard 0.13-μm BiCMOS technology. The antenna is efficiently designed to cover the bandwidth at 60 GHz band and easily satisfy the metal density rules and can be integrated with other circuitry in a standard process.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143972/1/hskims_1.pd

CMOS radio frequency circuits for short-range direct-conversion receivers

The research described in this thesis is focused on the design and implementation of radio frequency (RF) circuits for direct-conversion receivers. The main interest is in RF front-end circuits, which contain low-noise amplifiers, downconversion mixers, and quadrature local oscillator signal generation circuits. Three RF front-end circuits were fabricated in a short-channel CMOS process and experimental results are presented. A low-noise amplifier (LNA) is typically the first amplifying block in the receiver. A large number of LNAs have been reported in the literature. In this thesis, wideband LNA structures are of particular interest. The most common and relevant LNA topologies are analyzed in detail in the frequency domain and theoretical limitations are found. New LNA structures are presented and a comparison to the ones found in the literature is made. In this work, LNAs are implemented with downconversion mixers as RF front-ends. The designed mixers are based on the commonly used Gilbert cell. Different mixer implementation alternatives are presented and the design of the interface between the LNA and the downconversion mixer is discussed. In this work, the quadrature local oscillator signal is generated either by using frequency dividers or polyphase filters (PPF). Different possibilities for implementing frequency dividers are briefly described. Polyphase filters were already introduced by the 1970s and integrated circuit (IC) realizations to generate quadrature signals have been published since the mid-1990s. Although several publications where the performance of the PPFs has been studied either by theoretical calculations or simulations can be found in the literature, none of them covers all the relevant design parameters. In this thesis, the theory behind the PPFs is developed such that all the relevant design parameters needed in the practical circuit design have been calculated and presented with closed-form equations whenever possible. Although the main focus was on twoand three-stage PPFs, which are the most common ones encountered in practical ICs, the presented calculation methods can be extended to analyze the performance of multistage PPFs as well. The main application targets of the circuits presented in this thesis are the short-range wireless sensor system and ultrawideband (UWB). Sensors are capable of monitoring temperature, pressure, humidity, or acceleration, for example. The amount of transferred data is typically small and therefore a modest bit rate, less than 1 Mbps, is adequate. The sensor system applied in this thesis operates at 2.4-GHz ISM band (Industrial, Scientific, and Medical). Since the sensors must be able to operate independently for several years, extremely low power consumption is required. In sensor radios, the receiver current consumption is dominated by the blocks and elements operating at the RF. Therefore, the target was to develop circuits that can offer satisfactory performance with a current consumption level that is small compared to other receivers targeted for common cellular systems. On the other hand, there is a growing need for applications that can offer an extremely high data rate. UWB is one example of such a system. At the moment, it can offer data rates of up to 480 Mbps. There is a frequency spectrum allocated for UWB systems between 3.1 and 10.6 GHz. The UWB band is further divided into several narrower band groups (BG), each occupying a bandwidth of approximately 1.6 GHz. In this work, a direct-conversion RF front-end is designed for a dual-band UWB receiver, which operates in band groups BG1 and BG3, i.e. at 3.1 – 4.8 GHz and 6.3 – 7.9 GHz frequency areas, respectively. Clearly, an extremely wide bandwidth combined with a high operational frequency poses challenges for circuit design. The operational bandwidths and the interfaces between the circuit blocks need to be optimized to cover the wanted frequency areas. In addition, the wideband functionality should be achieved without using a number of on-chip inductors in order to minimize the die area, and yet the power consumption should be kept as small as possible. The characteristics of the two main target applications are quite different from each other with regard to power consumption, bandwidth, and operational frequency requirements. A common factor for both is their short, i.e. less than 10 meters, range. Although the circuits presented in this thesis are targeted on the two main applications mentioned above, they can be utilized in other kind of wireless communication systems as well. The performance of three experimental circuits was verified with measurements and the results are presented in this work. Two of them have been a part of a whole receiver including baseband amplifiers and filters and analog-to-digital converters. Experimental circuits were fabricated in a 0.13-µm CMOS process. In addition, this thesis includes design examples where new circuit ideas and implementation possibilities are introduced by using 0.13-µm and 65-nm CMOS processes. Furthermore, part of the theory presented in this thesis is validated with design examples in which actual IC component models are used.Tässä väitöskirjassa esitetty tutkimus keskittyy suoramuunnosvastaanottimen radiotaajuudella (radio frequency, RF) toimivien piirien suunnitteluun ja toteuttamiseen. Työ keskittyy vähäkohinaiseen vahvistimeen (low-noise amplifier, LNA), alassekoittajaan ja kvadratuurisen paikallisoskillaattorisignaalin tuottavaan piiriin. Työssä toteutettiin kolme RF-etupäätä erittäin kapean viivanleveyden CMOS-prosessilla, ja niiden kokeelliset tulokset esitetään. Vähäkohinainen vahvistin on yleensä ensimmäinen vahvistava lohko vastaanottimessa. Useita erilaisia vähäkohinaisia vahvistimia on esitetty kirjallisuudessa. Tämän työn kohteena ovat eritoten laajakaistaiset LNA-rakenteet. Tässä työssä analysoidaan taajuustasossa yleisimmät ja oleellisimmat LNA-topologiat. Lisäksi uusia LNA-rakenteita on esitetty tässä työssä ja niitä on verrattu muihin kirjallisuudessa esitettyihin piireihin. Tässä työssä LNA:t on toteutettu yhdessä alassekoittimen kanssa muodostaen RF-etupään. Työssä suunnitellut alassekoittimet perustuvat yleisesti käytettyyn Gilbertin soluun. Erilaisia sekoittajan suunnitteluvaihtoehtoja ja LNA:n ja alassekoittimen välisen rajapinnan toteutustapoja on esitetty. Tässä työssä kvadratuurinen paikallisoskillaattorisignaali on muodostettu joko käyttämällä taajuusjakajia tai monivaihesuodattimia. Erilaisia taajuusjakajia ja niiden toteutustapoja käsitellään yleisellä tasolla. Monivaihesuodatinta, joka on alunperin kehitetty jo 1970-luvulla, on käytetty integroiduissa piireissä kvadratuurisignaalin tuottamiseen 1990-luvun puolivälistä lähtien. Kirjallisuudesta löytyy lukuisia artikkeleita, joissa monivaihesuodattimen toimintaa on käsitelty teoreettisesti laskien ja simuloinnein. Kuitenkaan kaikkia sen suunnitteluparametreja ei tähän mennessä ole käsitelty. Tässä työssä monivaihesuodattimen teoriaa on kehitetty edelleen siten, että käytännön piirisuunnittelussa tarvittavat oleelliset parametrit on analysoitu ja suunnitteluyhtälöt on esitetty suljetussa muodossa aina kuin mahdollista. Vaikka työssä on keskitytty yleisimpiin eli kaksi- ja kolmiasteisiin monivaihesuodattimiin, on työssä esitetty menetelmät, joilla laskentaa voidaan jatkaa aina useampiasteisiin suodattimiin asti. Työssä esiteltyjen piirien pääkohteina ovat lyhyen kantaman sensoriradio ja erittäin laajakaistainen järjestelmä (ultrawideband, UWB). Sensoreilla voidaan tarkkailla esimerkiksi ympäristön lämpötilaa, kosteutta, painetta tai kiihtyvyyttä. Siirrettävän tiedon määrä on tyypillisesti vähäistä, jolloin pieni tiedonsiirtonopeus, alle 1 megabitti sekunnissa, on välttävä. Tämän työn kohteena oleva sensoriradiojärjestelmä toimii kapealla kaistalla 2,4 gigahertsin ISM-taajuusalueella (Industrial, Scientific, and Medical). Koska sensorien tavoitteena on toimia itsenäisesti ilman pariston vaihtoa useita vuosia, täytyy niiden kuluttaman virran olla erittäin vähäistä. Sensoriradiossa vastaanottimen tehonkulutuksen kannalta määräävässä asemassa ovat radiotaajuudella toimivat piirit. Tavoitteena oli tutkia ja kehittää piirirakenteita, joilla päästään tyydyttävään suorituskykyyn tehonkulutuksella, joka on vähäinen verrattuna muiden tavallisten langattomien tiedonsiirtojärjestelmien radiovastaanottimiin. Toisaalta viime aikoina on kasvanut tarvetta myös järjestelmille, jotka kykenevät tarjoamaan erittäin korkean tiedonsiirtonopeuden. UWB on esimerkki tällaisesta järjestelmästä. Tällä hetkellä se tarjoaa tiedonsiirtonopeuksia aina 480 megabittiin sekunnissa. UWB:lle on varattu taajuusalueita 3,1 ja 10,6 gigahertsin taajuuksien välillä. Kyseinen kaista on edelleen jaettu pienempiin taajuusryhmiin (band group, BG), joiden kaistanleveys on noin 1,6 gigahertsiä. Tässä työssä on toteutettu RF-etupää radiovastaanottimeen, joka pystyy toimimaan BG1:llä ja BG3:lla eli taajuusalueilla 3,1 - 4,7 GHz ja 6,3 - 7,9 GHz. Erittäin suuri kaistanleveys yhdistettynä korkeaan toimintataajuuteen tekee radiotaajuuspiirien suunnittelusta haasteellista. Piirirakenteiden toimintakaistat ja piirien väliset rajapinnat tulee optimoida riittävän laajoiksi käyttämättä kuitenkaan liian montaa piille integroitua kelaa piirin pinta-alan minimoimiseksi, ja lisäksi piirit tulisi toteuttaa mahdollisimman alhaisella tehonkulutuksella. Työssä esiteltyjen piirien kaksi pääkohdetta ovat hyvin erityyppisiä, mitä tulee tehonkulutus-, kaistanleveys- ja toimintataajuusvaatimuksiin. Yhteistä molemmille on lyhyt, alle 10 metrin kantama. Vaikka tässä työssä esitellyt piirit onkin kohdennettu kahteen pääsovelluskohteeseen, voidaan esitettyjä piirejä käyttää myös muiden tiedonsiirtojärjestelmien piirien suunnitteluun. Tässä työssä esitetään mittaustuloksineen yhteensä kolme kokeellista piiriä yllämainittuihin järjestelmiin. Kaksi ensimmäistä kokeellista piiriä muodostaa kokonaisen radiovastaanottimen yhdessä analogisten kantataajuusosien ja analogia-digitaali-muuntimien kanssa. Esitetyt kokeelliset piirit on toteutettu käyttäen 0,13 µm:n viivanleveyden CMOS-tekniikkaa. Näiden lisäksi työ pitää sisällään piirisuunnitteluesimerkkejä, joissa esitetään ideoita ja mahdollisuuksia käyttäen 0,13 µm:n ja 65 nm:n viivanleveyden omaavia CMOS-tekniikoita. Lisäksi piirisuunnitteluesimerkein havainnollistetaan työssä esitetyn teorian paikkansapitävyyttä käyttämällä oikeita komponenttimalleja.reviewe

Continuous-time low-pass filters for integrated wideband radio receivers

This thesis concentrates on the design and implementation of analog baseband continuous-time low-pass filters for integrated wideband radio receivers. A total of five experimental analog baseband low-pass filter circuits were designed and implemented as a part of five single-chip radio receivers in this work. After the motivation for the research work presented in this thesis has been introduced, an overview of analog baseband filters in radio receivers is given first. In addition, a review of the three receiver architectures and the three wireless applications that are adopted in the experimental work of this thesis is presented. The relationship between the integrator non-idealities and integrator Q-factor, as well as the effect of the integrator Q-factor on the filter frequency response, are thoroughly studied on the basis of a literature review. The theoretical study that is provided is essential for the gm-C filter synthesis with non-ideal lossy integrators that is presented after the introduction of different techniques to realize integrator-based continuous-time low-pass filters. The filter design approach proposed for gm-C filters is original work and one of the main points in this thesis, in addition to the experimental IC implementations. Two evolution versions of fourth-order 10-MHz opamp-RC low-pass filters designed and implemented for two multicarrier WCDMA base-station receivers in a 0.25-µm SiGe BiCMOS technology are presented, along with the experimental results of both the low-pass filters and the corresponding radio receivers. The circuit techniques that were used in the three gm-C filter implementations of this work are described and a common-mode induced even-order distortion in a pseudo-differential filter is analyzed. Two evolution versions of fifth-order 240-MHz gm-C low-pass filters that were designed and implemented for two single-chip WiMedia UWB direct-conversion receivers in a standard 0.13-µm and 65-nm CMOS technology, respectively, are presented, along with the experimental results of both the low-pass filters and the second receiver version. The second UWB filter design was also embedded with an ADC into the baseband of a 60-GHz 65-nm CMOS radio receiver. In addition, a third-order 1-GHz gm-C low-pass filter was designed, rather as a test structure, for the same receiver. The experimental results of the receiver and the third gm-C filter implementation are presented

CIRCUIT MODULES FOR BROADBAND CMOS SIX-PORT SYSTEMS

This dissertation investigates four circuit modules used in a CMOS integrated six-port measurement system. The first circuit module is a wideband power source generator, which can be implemented with a voltage controlled ring oscillator. The second circuit module is a low-power 0.5 GHz - 20.5 GHz power detector with an embedded amplifier and a wideband quasi T-coil matching network. The third circuit module is a six-port circuit, which can be implemented with distributed or lumped- lement techniques. The fourth circuit module is the phase sifter used as calibration loads. The theoretical analysis, circuit design, simulated or experimental verifications of each circuit module are also included

Advances in Integrated Circuit Design and Implementation for New Generation of Wireless Transceivers

User’s everyday outgrowing demand for high-data and high performance mobile devices pushes industry and researchers into more sophisticated systems to fulfill those expectations. Besides new modulation techniques and new system designs, significant improvement is required in the transceiver building blocks to handle higher data rates with reasonable power efficiency. In this research the challenges and solution to improve the performance of wireless communication transceivers is addressed. The building block that determines the efficiency and battery life of the entire mobile handset is the power amplifier. Modulations with large peak to average power ratio severely degrade efficiency in the conventional fixed-biased power amplifiers (PAs). To address this challenge, a novel PA is proposed with an adaptive load for the PA to improve efficiency. A nonlinearity cancellation technique is also proposed to improve linearity of the PA to satisfy the EVM and ACLR specifications. Ultra wide-band (UWB) systems are attractive due to their ability for high data rate, and low power consumption. In spite of the limitation assigned by the FCC, the coexistence of UWB and NB systems are still an unsolved challenge. One of the systems that is majorly affected by the UWB signal, is the 802.11a system (5 GHz Wi-Fi). A new analog solution is proposed to minimize the interference level caused by the impulse Radio UWB transmitter to nearby narrowband receivers. An efficient 400 Mpulse/s IR-UWB transmitter is implemented that generates an analog UWB pulse with in-band notch that covers the majority of the UWB spectrum. The challenge in receiver (RX) design is the over increasing out of blockers in applications such as cognitive and software defined radios, which are required to tolerate stronger out-of-band (OB) blockers. A novel RX is proposed with a shunt N-path high-Q filter at the LNA input to attenuate OB-blockers. To further improve the linearity, a novel baseband blocker filtering techniques is proposed. A new TIA has been designed to maintain the good linearity performance for blockers at large frequency offsets. As a result, a +22 dBm IIP3 with 3.5 dB NF is achieved. Another challenge in the RX design is the tough NF and linearity requirements for high performance systems such as carrier aggregation. To improve the NF, an extra gain stage is added after the LNA. An N-path high-Q band-pass filter is employed at the LNA output together with baseband blocker filtering technique to attenuate out-of-band blockers and improve the linearity. A noise-cancellation technique based on the frequency translation has been employed to improve the NF. As a result, a 1.8dB NF with +5 dBm IIP3 is achieved. In addition, a new approach has been proposed to reject out of band blockers in carrier aggregation scenarios. The proposed solution also provides carrier to carrier isolation compared to typical solution for carrier aggregation

Analysis and Design of Radio Frequency Integrated Circuits for Breast Cancer Radar Imaging in CMOS Technology

Breast cancer is by far the most incident tumor among female population. Early stage prevention is a key factor in delivering long term survival of breast cancer patients. X-ray mammography is the most commonly used diagnostic technique to detect non-palpable tumors. However, 10-30% of tumors are missed by mammography and ionizing radiations together with breast compression do not lead to comfort in patient treatment. In this context, ultrawideband microwave radar technology is an attractive alternative. It relies on the dielectric contrast of normal and malignant tissues at microwave frequencies to detect and locate tumors inside the breast. This work presents the analysis and design of radio frequency integrated circuits for breast cancer imaging in CMOS technology. The first part of the thesis concerns the system analysis. A behavioral model of two different transceiver architectures for UWB breast cancer imaging employing a SFCW radar system are presented. A mathematical model of the direct conversion and super heterodyne architectures together with a numerical breast phantom are developed. FDTD simulations data are used to on the behavioral model to investigate the limits of both architectures from a circuit-level point of view. Insight is given into I/Q phase inaccuracies and their impact on the quality of the final reconstructed images. The result is that the simplicity of the direct conversion architecture makes the receiver more robust toward the critical impairments for this application. The second part of the thesis is dedicated to the circuit design. The main achievement is a 65nm CMOS 2-16GHz stepped frequency radar transceiver for medical imaging. The RX features 36dB conversion gain, >29dBm compression point, 7dB noise figure, and 30Hz 1/f noise corner. The TX outputs 14dBm with >40dBc harmonic rejection and <109dBc/Hz phase noise at 1MHz offset. Overall power dissipation is 204mW from 1.2V supply. The radar achieves 3mm resolution within the body, and 107dB dynamic range, a performance enabling the use for breast cancer diagnostic imaging. To further assess the capabilities of the proposed radar, a physical breast phantom was synthesized and two targets mimicking two tumors were buried inside the breast. The targets are clearly identified and correctly located, effectively proving the performance of the designed radar as a possible tool for breast cancer detection

Ultra-Wideband Transceiver Design And Optimization

University of Minnesota Ph.D. dissertation. July 2015. Major: Electrical Engineering. Advisor: Ramesh Harjani. 1 computer file (PDF); xiii, 128 pages.The technology landscape has quickly changed over the last few years. Developments in personal area networks, IC technology, DSP processing and bio-medical devices have enabled the integration of short range communication into low cost personal health care solutions. Newer technologies and solutions are being developed to cater to the personal operating space(POS) and body area networks(BAN). Health care is driving towards using multiple sensor and therapeutic nodes inside the POS. Technology has enabled remote patient care where the patient has low cost on-body wearables that allow the patient/physician to access vital signs without the patient physically visiting the clinic. Big semiconductor giants want to move into the wearable health monitor space. Along with the developments in fitness based health wearables, there has been a lot of interest towards developing BAN devices catering to the 'mission-critical' wearables and implants. Hearing aids, EKG monitors, neurostimulators are some examples. This work explores the use of the 802.15 ulta wideband (UWB) standard for designing a radio to operate in the a wireless sensor network in the BAN. The specific application targeted is a hearing aid. However, the design in this work is capable of working in a low power low range application with the ability to have multiple data rates ranging from a few kHz to 10's of MHz. The first radio designed by Marconi using spark-gap transmitters was an impulse radio (IR). The IR UWB technology boasts of low power, low cost, high data rates, multiple channels, simultaneous networking, the ability to carry information through obstacles that more limited bandwidths cannot, and also potentially lower complexity hardware design. The inherent timing accuracy associated with the technology gives UWB transmissions immunity to multipath fading and are hence make them more suitable for a cluttered indoor environment. The key difference with the traditional narrowband transceiver is that instead of using continuous wave (CW) transmission, impulses in time are used. The timing accuracy associated with these impulses require synchronization in time, rather than synchronization in frequency for carrier-based CW systems. A complete fully integrated system is presented in thesis. This work presents a low-power noncoherent IR UWB transceiver operating at 5GHz in 0.13um CMOS. A fully-digital transmitter generates a shaped output pulse of 1GHz 3-dB bandwidth. DLLs provide a PVT-tolerant time-step resolution of 1ns over the entire symbol period and regulate the pulse generator center frequency. The transmitter outputs -31dBm (0.88pJ/pulse at 1Mpulse/s) with a dynamic (energy) efficiency of 16pJ/pulse. The transmit out pulse is FCC part 15 compliant over process voltage and temperature (PVT) variations. The transmitter is semi-compliant with IEEE 802.15.6 and IEEE 802.15.4 standards and will become completely compliant with minor modifications. The receiver presented in this work is a non-coherent energy detect IR UWB receiver. The receiver has an on-chip transformer preceding the LNA, which is followed by a super-regenerative amplifier (SRA), envelope detector, sample-and-holds, and a bank of comparators. The design is SRA based energy-detection receiver. Measured results show a receiver efficiency of 0.32nJ/bit at 20.8Mb/s and operation with inputs as low as -70dBm. The SRA based energy-detection receiver utilizes early/late detection for a two-step baseband synchronization algorithm. An integrated solution to the issue of synchronization is also proposed. The system proposed is capable of synchronization and tracking control. The system in this work utilizes early/late detection for a two-step baseband synchronization algorithm. The algorithm is implemented in Matlab and the time to synchronization is observed to be between 250us to a few couple of ms. Measurements have also been made using the receiver and manually implementing the algorithm. This work addresses all aspects time synchronization in an IR transceiver. The initial mismatch is addressed by two methods. Beyond the initial synchronization, the system presented in this system is also capable of tracking. This would mean that once the transceiver has been synchronized, the timing generation would continue to track the phase and the frequency changes depending upon crystal drift over time or movement between the receiver and the transmitter. A test was also performed on the complete transceiver system with two radios talking to each other over a highly attenuated wired channel