A Q-enhanced 3.6 GHz tunable CMOS bandpass filter for wideband wireless applications

With the rapid development of information technology, more and more bandwidth is required to transmit multimedia data. Since local communication networks are moving to wireless domain, it brings up great challenges for making integrated wideband wireless front-ends suitable for these applications. RF filtering is a fundamental need in all wireless front-ends and is one of the most difficult parts to be integrated. This has been a major obstacle to the implementation of low power and low cost integrated wireless terminals. Lots of previous work has been done to make integrated RF filters applicable to these applications. However, some of these filters are not designed with standard CMOS technology. Some of them are not designed in desired frequency bands and others do not have sufficient frequency bandwidth. This research demonstrates the design of a tunable wideband RF filter that operates at 3.6 GHz and can be easily changed to a higher frequency range up to 5 GHz. This filter is superior to the previous designs in the following aspects: a) wider bandwidth, b) easier to tune, c) balancing in noise and linearity, and d) using standard CMOS technology. The design employs the state-of-the-art inductor degenerated LNA, acting as a transconductor to minimize the overall noise figure. A Q-enhancement circuit is employed to compensate the loss from lossy on-chip spiral inductors. Center frequency and bandwidth tuning circuits are also embedded to make the filter suitable for multi band operations. At first, a second order bandpass filter prototype was designed in the standard 0.18 ìm CMOS process. Simulation results showed that at 3.6 GHz center frequency and with a 60-MHz bandwidth, the input third-order intermodulation product (IIP3) and input-referred 1 dB compression point (P1dB) was -22.5 dBm and -30.5 dBm respectively. The image rejection at 500 MHz away from the center frequency was 32 dB (250 MHz intermediate frequency). The Q of the filter was tunable over 3000 and the center frequency tuning range was about 150 MHz. By cascading three stages of second order filters, a sixth order filter was designed to enhance the image rejection ability and to extend the filter bandwidth. The sixth order filter had been fabricated in the standard 0.18 ìm CMOS process using 1.8-V supply. The chip occupies only 0.9 mm 0.9 mm silicon area and has a power consumption of 130-mW. The measured center frequency was tunable from 3.54 GHz to 3.88 GHz, bandwidth was tunable from 35 MHz to 80 MHz. With a 65 MHz bandwidth, the filter had a gain of 13 dB, an IIP3 of -29 dBm and a P1dB of -46 dBm

Vidutinių dažnių 5G belaidžių tinklų galios stiprintuvų tyrimas

This dissertation addresses the problems of ensuring efficient radio fre-quency transmission for 5G wireless networks. Taking into account, that the next generation 5G wireless network structure will be heterogeneous, the device density and their mobility will increase and massive MIMO connectivity capability will be widespread, the main investigated problem is formulated – increasing the efficiency of portable mid-band 5G wireless network CMOS power amplifier with impedance matching networks. The dissertation consists of four parts including the introduction, 3 chapters, conclusions, references and 3 annexes. The investigated problem, importance and purpose of the thesis, the ob-ject of the research methodology, as well as the scientific novelty are de-fined in the introduction. Practical significance of the obtained results, defended state-ments and the structure of the dissertation are also included. The first chapter presents an extensive literature analysis. Latest ad-vances in the structure of the modern wireless network and the importance of the power amplifier in the radio frequency transmission chain are de-scribed in detail. The latter is followed by different power amplifier archi-tectures, parameters and their improvement techniques. Reported imped-ance matching network design methods are also discussed. Chapter 1 is concluded distinguishing the possible research vectors and defining the problems raised in this dissertation. The second chapter is focused around improving the accuracy of de-signing lumped impedance matching network. The proposed methodology of estimating lumped inductor and capacitor parasitic parameters is dis-cussed in detail provi-ding complete mathematical expressions, including a summary and conclusions. The third chapter presents simulation results for the designed radio fre-quency power amplifiers. Two variations of Doherty power amplifier archi-tectures are presented in the second part, covering the full step-by-step de-sign and simulation process. The latter chapter is concluded by comparing simulation and measurement results for all designed radio frequency power amplifiers. General conclusions are followed by an extensive list of references and a list of 5 publications by the author on the topic of the dissertation. 5 papers, focusing on the subject of the discussed dissertation, have been published: three papers are included in the Clarivate Analytics Web of Sci-ence database with a citation index, one paper is included in Clarivate Ana-lytics Web of Science database Conference Proceedings, and one paper has been published in unreferred international conference preceedings. The au-thor has also made 9 presentations at 9 scientific conferences at a national and international level.Dissertatio

Integration of broadband direct-conversion quadrature modulators

To increase spectral efficiency, transmitters usually send only one of the information carrying sidebands centered around a single radio-frequency carrier. The close-lying mirror, or image, sideband will be eliminated either by the filtering method or by the phasing method. Since filter Q-values rise in direct relation to the transmitted frequencies, the filtering method is generally not feasible for integrated microwave transmitters. A quadrature modulator realizes the phasing method by combining signals phased at quadrature (i.e. at 90° offsets) to produce a single-sideband (SSB) output. In this way output filtering can be removed or its specifications greatly relieved so as to produce an economical microwave transmitter. The proliferation of integrated circuit (IC) technologies since the 1980s has further boosted the popularity of quadrature modulator as an IC realization makes possible the economical production of two closely matched doubly balanced mixers, which suppress carrier and even-order spurious leakage to circuit output. Another strength of IC is its ability to perform microwave quadrature generation accurately on-chip, and thereby to avoid most of the interconnect parasitics which could ruin high-frequency quadrature signaling. Nevertheless, all quadrature modulator implementations are sensitive to phasing and amplitude errors, which are born as a result of mismatches, from the use of inaccurate differential signaling, and from inadequacies in the phasing circuitry itself. A 2° phase error is easily produced, and it reduces the image-rejection ratio (IRR) to −30 dBc. Therefore, as baseband signals synthesized by digital signal processing (DSP) are sufficiently accurate, this thesis concentrates on analyzing and producing the microwave signal path of a direct-conversion quadrature modulator with special emphasis on broadband, multimode radio-compatible operation. A model of the direct-conversion quadrature modulator operation has been developed, which reveals the effect the circuit non-linearities and mismatch-related offsets have on available performance. Further, theoretical proof is given of the well-known property of improving differential signal balance that cascaded differential pairs exhibit. Among the practical results, a current reuse mixer has been developed, which improves the transmitted signal-to-noise-ratio (SNR) by 3 dB, with a maximum measured dynamic range of +158 dB. The complementary bipolar process was further used to extend the bipolar push-pull stage bandwidth to 9.5 GHz. At the core of this work is the parallel switchable polyphase (PP) filter quadrature generator that was developed, since it makes possible accurate broadband IQ generation without the high loss that usually results from the application of PP filtering. Two IQ modulator prototypes were realized to test simulated and theoretically derived data: the 0.8 µm SiGe IC achieves an IRR better than −40 dBc over 0.75-3.6 GHz, while the 0.13 µm digital bulk CMOS IC achieves better than −37 dBc over 0.56-4.76 GHz. For this IRR performance the SiGe prototype boasts the inexpensive solution of integrated baluns, while the CMOS one utilizes a coil-transmission line hybrid transformer at its LO input to drive the switchable PP filters.Taajuuksien käytön tehostamiseksi lähettimet lähettävät yleensä vain toisen informaatiota sisältävistä sivukaistoistaan yhdelle radiotaajuuksiselle kantoaallolle keskitettynä. Viereinen peilitaajuus eli sivukaista vaimennetaan joko suodattamalla tai vaiheistamalla signalointia sopivasti. Koska suodattimen hyvyysluvut nousevat suorassa suhteessa käytettyyn taajuuteen, ei suodatusmenetelmä ole yleensä mahdollinen mikroaaltotaajuusalueen lähettimissä. Kvadratuurimodulaattori toteuttaa vaiheistusmenetelmän yhdistämällä 90-asteen vaihesiirroksin vaiheistetut signaalit yksisivukaistaisen lähetteen tuottamiseksi. Näin voidaan korvata lähdön suodatus joko kokonaan tai lieventämällä vaadittavia suoritusarvoja, jolloin mikroaaltoalueen lähetin voidaan tuottaa taloudellisesti. Integroitujen piiriratkaisujen yleistyminen 1980-luvulta lähtien on edesauttanut kvadratuurimodulaattorin suosiota, koska integroidulle piirille voidaan taloudellisesti tuottaa kaksi hyvin ominaisuuksiltaan toisiaan vastaavaa kaksoisbalansoitua sekoitinta, ja nämä tunnetusti vaimentavat kantoaaltovuotoa ja parillisia harmoonisia piirin lähdössä. Toinen integroitujen piirien vahvuus on kyky tarkkaan mikroaaltoalueen kvadratuurisignalointiin samalla piirillä, jolloin vältetään suurin osa kytkentöjen parasiittisista jotka muutoin voisivat tuhota korkeataajuuksisen 90-asteen vaiheistuksen. Kaikki kvadratuurimodulaattorit ovat joka tapauksessa herkkiä vaiheistus- ja amplitudieroille, joita syntyy komponenttiarvojen satunnaishajonnasta, epätarkan differentiaalisen signaloinnin käytöstä, ja itse vaiheistuspiiristön puutteellisuuksista. Kahden asteen vaihevirhe syntyy helposti, ja tällöin sivukaistavaimennus heikkenee -30 dBc:n tasolle. Tämänvuoksi, ja olettaen että digitaalisella signaaliprosessorilla luotu kantataajuuksinen signalointi on riittävän tarkkaa, tämä väitöskirja keskittyy kvadratuurimodulaattorin mikroaaltotaajuuksisen signaalipolun analysointiin ja tuottamiseen painottaen erityisesti laajakaistaista, monisovellusradioiden kanssa yhteensopivaa toimivuutta. Kvadratuurimodulaattorin toimintamallia on kehitetty siten, että mallissa huomioidaan epälineaarisuuksien ja piirielementtien satunnaishajontojen vaikutus saavutettavalle suorituskyvylle. Lisäksi on teoreettisesti todistettu sinänsä hyvin tunnettu peräkkäin kytkettyjen vahvistinasteiden differentiaalisen signaloinnin symmetrisyyttä parantava vaikutus. Käytännön tuloksista voidaan mainita kehitetty virtaakierrättävä sekoitin, joka parantaa signaali-kohinasuhdetta +3 dB, suurimman mitatun dynaamisen alueen ollessa +158 dB. Samaa komplementaarista bipolaariprosessia käytettiin edelleen bipolaarisen vuorovaihe-asteen kaistan levittämisessä 9.5 GHz:iin. Yhtenä tämän työn tärkeimmistä tuloksista on kehitetty kytkimin valittavista rinnakkaisista monivaihesuodattimista koostuva kvadratuurigeneraattori, jolla on mahdollista tuottaa laajakaistaista IQ-signalointia ilman suurta häviötä joka yleensä liittyy monivaihesuodattimien käyttöön. Kaksi IQ-modulaattoriprototyyppiä toteutettiin simuloitujen ja teoreettisesti mallinnettujen tulosten testaamiseksi: 0.8 µm SiGe integroitu piiri saavuttaa paremman sivukaistavaimennuksen kuin -40 dBc yli 0.75-3.6 GHz, kun taas 0.13 µm digitaalipiirien tuottamiseen tarkoitetulla CMOS prosessilla toteutettu integroitu piiri saavuttaa paremman sivukaistavaimennuksen kuin -37 dBc taajuusalueella 0.56-4.76 GHz. Näihin sivukaistavaimennuksiin SiGe prototyyppi pääsee edullisesti integroiduin symmetrointimuuntajin, kun taas CMOS piirillä käytetään kela-siirtojohto-tyyppistä yhdistelmämuuntajaa LO-sisääntulossa josta ajetaan erikseen kytkettäviä monivaihesuodattimia.reviewe

Dynamically Controllable Integrated Radiation and Self-Correcting Power Generation in mm-Wave Circuits and Systems

This thesis presents novel design methodologies for integrated radiators and power generation at mm-wave frequencies that are enabled by the continued integration of various electronic and electromagnetic (EM) structures onto the same substrate. Beginning with the observation that transistors and their connections to EM radiating structures on an integrated substrate are essentially free, the concept of multi-port driven (MPD) radiators is introduced, which opens a vast design space that has been generally ignored due to the cost structure associated with discrete components that favors fewer transistors connected to antennas through a single port. From Maxwell's equations, a new antenna architecture, the radial MPD antennas based on the concept of MPD radiators, is analyzed to gain intuition as to the important design parameters that explain the wide-band nature of the antenna itself. The radiator is then designed and implemented at 160 GHz in a 0.13 um SiGe BiCMOS process, and the single element design has a measured effective isotropic radiated power (EIRP) of +4.6 dBm with a total radiated power of 0.63 mW. Next, the radial MPD radiator is adapted to enable dynamic polarization control (DPC). A DPC antenna is capable of controlling its radiated polarization dynamically, and entirely electronically, with no mechanical reconfiguration required. This can be done by having multiple antennas with different polarizations, or within a single antenna that has multiple drive points, as in the case of the MPD radiator with DPC. This radiator changes its polarization by adjusting the relative phase and amplitude of its multiple ports to produce polarizations with any polarization angle, and a wide range of axial ratios. A 2x1 MPD radiator array with DPC at 105 GHz is presented whose measurements show control of the polarization angle throughout the entire 0 degree through 180 degree range while in the linear polarization mode and maintaining axial ratios above 10 dB in all cases. Control of the axial ratio is also demonstrated with a measured range from 2.4 dB through 14 dB, while maintaining a fixed polarization angle. The radiator itself has a measured maximum EIRP of +7.8 dBm, with a total radiated power of 0.9 mW, and is capable of beam steering. MPD radiators were also applied in the domain of integrated silicon photonics. For these designs, the driver transistor circuitry was replaced with silicon optical waveguides and photodiodes to produce a 350 GHz signal. Three of these optical MPD radiator designs have been implemented as 2x2 arrays at 350 GHz. The first is a beam forming array that has a simulated gain of 12.1 dBi with a simulated EIRP of -2 dBm. The second has the same simulated performance, but includes optical phase modulators that enable two-dimensional beam steering. Finally, a third design incorporates multi-antenna DPC by combining the outputs of both left and right handed circularly polarized MPD antennas to produce a linear polarization with controllable polarization angle, and has a simulated gain of 11.9 dBi and EIRP of -3 dBm. In simulation, it can tune the polarization from 0 degrees through 180 degrees while maintaining a radiated power that has a 0.35 dB maximum deviation from the mean. The reliability of mm-wave radiators and power amplifiers was also investigated, and two self-healing systems have been proposed. Self-healing is a global feedback method where integrated sensors detect the performance of the circuit after fabrication and report that data to a digital control algorithm. The algorithm then is capable of setting actuators that can control the performance of the mm-wave circuit and counteract any performance degradation that is observed by the sensors. The first system is for a MPD radiator array with a partially integrated self-healing system. The self-healing MPD radiator senses substrate modes through substrate mode pickup sensors and infers the far-field radiated pattern from those sensors. DC current sensors are also included to determine the DC power consumption of the system. Actuators are implemented in the form of phase and amplitude control of the multiple drive points. The second self-healing system is a fully integrated self-healing power amplifier (PA) at 28 GHz. This system measures the output power, gain and efficiency of the PA using radio frequency (RF) power sensors, DC current sensors and junction temperature sensors. The digital block is synthesized from VHDL code on-chip and it can actuate the output power combining matching network using tunable transmission line stubs, as well as the DC operating point of the amplifying transistors through bias control. Measurements of 20 chips confirm self-healing for two different algorithms for process variation and transistor mismatch, while measurements from 10 chips show healing for load impedance mismatch, and linearity healing. Laser induced partial and total transistor failure show the benefit of self-healing in the case of catastrophic failure, with improvements of up to 3.9 dB over the default case. An exemplary yield specification shows self-healing improving the yield from 0% up through 80%.</p

Broadband phase shifter design for phased array radar systems

Ph.DDOCTOR OF PHILOSOPH

Above-IC RF MEMS devices for communication applications

Wireless communications are showing an explosive growth in emerging consumer and military applications of radiofrequency (RF), microwave, and millimeter-wave circuits and systems. Applications include wireless personal connectivity (Bluetooth), wireless local area networks (WLAN), mobile communication systems (GSM, GPRS, UMTS, CDMA), satellite communications and automotive electronics. Future cell phones and ground communication systems as well as communication satellites will require more and more sophisticated technologies. The increasing demand for size and weight reduction, cost savings, low power consumption, increased frequency and higher functionality and reconfigurability as part of multiband and multistandard operation is necessitating the use of highly integrated RF front-end circuits. Chip scaling has made a major contribution to this goal, but today a situation has been reached where the presence of numerous off-chip passive RF components imposes a critical bottleneck to further integration and miniaturization of wireless transceivers. Microelectromechanical systems (MEMS) technology is a rapidly emerging enabling technology that is intended to replace the discrete passives by their integrated counterparts. In this thesis, an original metal surface micromachining process, which is compatible with CMOS post-processing, for above-IC integration of RF MEMS tunable capacitors and suspended inductors is presented. A detailed study on SF6 inductively coupled plasma (ICP) releasing has been performed in order to ascertain the optimal process parameters. This study has emphasized the fact that temperature plays an important role in this process by limiting silicon dioxide etching. Moreover, the optimized recipe has been found to be independent of the sacrificial layer used (amorphous or polycrystalline silicon) and its thickness. Using this recipe, 15.6 µm/min Si underetch rate with high Si: SiO2 selectivity (> 20000: 1) has been obtained. Single-air-gap and double-air-gap parallel-plate MEMS tunable capacitors have been designed, fabricated and characterized in the pF range, from 1 MHz to 13.5 GHz. It has been shown that an optimized design of the suspended membrane and direct symmetrical current feed at both ports can significantly improve the quality factor and increase the self-resonant frequency, pushing it to 12 GHz and beyond. The maximum capacitance tuning range obtained for a single-air-gap capacitor is 29% for a bias voltage of 20 V. The maximum capacitance tuning range obtained for a double-air-gap capacitor is 207% for a bias voltage of 70 V. The post-processing of X-FAB BiCMOS wafers has been successfully demonstrated to fabricate monolithically integrated VCOs with above-IC MEMS LC tank. Comparing a suspended inductor and the X-FAB inductor with the same design, it has been shown that increasing the thickness of the spiral from 2.3 to 4 µm and having the spiral suspended 3 µm above the passivation layers lead to an improvement factor of 2 for the peak quality factor and a shift of the self-resonant frequency beyond 15 GHz. No significant variation on bipolar and MOS transistors characteristics due to the post-processing has been observed and we conclude that the variation due to post-processing is in the same range as the wafer-to-wafer variation. Based on our metal surface micromachining process, coplanar waveguide (CPW) MEMS shunt capacitive switches and variable true-time delay lines (V-TTDLs) have been designed, fabricated and characterized in the 1 - 20 GHz range. A novel MEMS device architecture: the SG-MOSFET, which combines a solid-state MOS transistor and a metal suspended gate has been proposed as DC current switch. The corresponding fabrication process using polysilicon as a sacrificial layer has been developed to release metal gate suspended over gate oxide by SF6 plasma. Very abrupt current switches have been demonstrated with subthreshold slope better than 10 mV/decade (better than the theoretical solid-state bulk or SOI MOSFET limit of 60 mV/decade) and ultra-low gate leakage (less than 0.001 pA/µm2) due to the air-gap

Concepts for Short Range Millimeter-wave Miniaturized Radar Systems with Built-in Self-Test

This work explores short-range millimeter wave radar systems, with emphasis on miniaturization and overall system cost reduction. The designing and implementation processes, starting from the system level design considerations and characterization of the individual components to final implementation of the proposed architecture are described briefly. Several D-band radar systems are developed and their functionality and performances are demonstrated

Advanced High Efficiency Architectures for Next Generation Wireless Communications

L'abstract è presente nell'allegato / the abstract is in the attachmen