Bidirectional common-path for 8-to-24 gHz low noise SiGe BiCMOS T/R module core-chip

This thesis is based on the design of an 8-to-24 GHz low noise SiGe BiCMOS Transmitter/Receiver (T/R) Module core-chip in a small area by bidirectional common-path. The next-generation phased array systems require multi-functionality and multi-band operation to form multi-purpose integrated circuits. Wide bandwidth becomes a requirement for the system in various applications, such as electronic warfare, due to leading cheaper and lighter system solutions. Although III-V technologies can satisfy the high-frequency specifications, they are expensive and have a large area. The silicon-based technologies promise high integration capability with low cost, but they sacrifice from the performance to result in desired bandwidth. The presented dissertation targets system and circuit level solutions on the described content. The wideband core-chip utilized a bidirectional common path to surpass the bandwidth limitations. The bidirectionality enhances the bandwidth, noise, gain and area of the transceiver by the removal of the repetitive blocks in the unidirectional common chain. This approach allows succeeding desired bandwidth and compactness without sacrificing from the other high-frequency parameters. The realized core-chip has 31.5 and 32 dB midband gain for the receiver and transmitter respectively, with a + 2.1 dB /GHz of positive slope. Its RMS phase and amplitude errors are lower than 5.60 and 0.8 dB, respectively for 4-bit of resolution. The receiver noise figure is lower than 5 dB for the defined bandwidth while dissipating 112 mW of power in a 5.5 mm2 area. The presented results verify the advantage of the favored architecture and might replace the III-V based counterparts

Four-element phased-array beamformers and a self-interference canceling full-duplex transciver in 130-nm SiGe for 5G applications at 26 GHz

This thesis is on the design of radio-frequency (RF) integrated front-end circuits for next generation 5G communication systems. The demand for higher data rates and lower latency in 5G networks can only be met using several new technologies including, but not limited to, mm-waves, massive-MIMO, and full-duplex. Use of mm-waves provides more bandwidth that is necessary for high data rates at the cost of increased attenuation in air. Massive-MIMO arrays are required to compensate for this increased path loss by providing beam steering and array gain. Furthermore, full duplex operation is desirable for improved spectrum efficiency and reduced latency. The difficulty of full duplex operation is the self-interference (SI) between transmit (TX) and receive (RX) paths. Conventional methods to suppress this interference utilize either bulky circulators, isolators, couplers or two separate antennas. These methods are not suitable for fully-integrated full-duplex massive-MIMO arrays. This thesis presents circuit and system level solutions to the issues summarized above, in the form of SiGe integrated circuits for 5G applications at 26 GHz. First, a full-duplex RF front-end architecture is proposed that is scalable to massive-MIMO arrays. It is based on blind, RF self-interference cancellation that is applicable to single/shared antenna front-ends. A high resolution RF vector modulator is developed, which is the key building block that empowers the full-duplex frontend architecture by achieving better than state-of-the-art 10-b monotonic phase control. This vector modulator is combined with linear-in-dB variable gain amplifiers and attenuators to realize a precision self-interference cancellation circuitry. Further, adaptive control of this SI canceler is made possible by including an on-chip low-power IQ downconverter. It correlates copies of transmitted and received signals and provides baseband/dc outputs that can be used to adaptively control the SI canceler. The solution comes at the cost of minimal additional circuitry, yet significantly eases linearity requirements of critical receiver blocks at RF/IF such as mixers and ADCs. Second, to complement the proposed full-duplex front-end architecture and to provide a more complete solution, high-performance beamformer ICs with 5-/6- b phase and 3-/4-b amplitude control capabilities are designed. Single-channel, separate transmitter and receiver beamformers are implemented targeting massive- MIMO mode of operation, and their four-channel versions are developed for phasedarray communication systems. Better than state-of-the-art noise performance is obtained in the RX beamformer channel, with a full-channel noise figure of 3.3 d

Electro-Photonic Transmitter Front-Ends for High-Speed Fiber-Optic Communication

This thesis addresses basic scientific research in the field of transmitter front-end circuits for electro-optical data communication. First, the theoretical fundamentals are presented and analyzed. Based on the theoretical considerations, conceptual circuit designs are studied. Finally, in order to prove the described concepts, the circuits were experimentally characterized and subsequently compared to other works in the literature. The analysis covers key theoretical aspects regarding transmitter front-end circuits. It starts from the basic physical effects inside a transistor and ends with the design of high-swing modulator drivers. Furthermore, it comprises the fundamentals of optical modulators as well as the integration of the electrical driver with the modulator. First, the concept of a basic monolithically integrated transmitter consisting of a Mach-Zehnder modulator (MZM) and an electrical driver is presented. The circuit reaches a bit-error-free data rate of 37 Gb/s, which is a record among other monolithically integrated transmitters reported in the literature. It was shown that by employing a high-swing driver, high extinction ratios (ER) can be achieved (namely 8.4 dB at 25 Gb/s and 7.6 dB at 35 Gb/s) while using short-length phase shifters (2 mm of length). It was therefore proved that one of the main drawbacks of the MZM-based transmitters, namely their large chip area, can be mitigated by using high-swing drivers, however without sacrificing the ER. Next, an improved modulator driver design is investigated, the focus of the study being the linearity. In addition to a high peak-to-peak differential output voltage swing of 7.2 Vpp,d, the driver achieves record-low total harmonic distortion (THD) values of 1% (at 1 GHz, for the output swing of 6.5 Vpp,d) and 1.7% (at 1 GHz, for the output swing of 7 Vpp,d). Moreover, the driver reaches a bandwidth of 61.2 GHz and shows a high power efficiency when relating its DC power consumption to its output voltage swing. The achievement of a high linearity and bandwidth without an increased power consumption is due to the fact that the bias currents of the emitter-follower (EF) stages are provided by means of resistors instead of the conventional current sources. The two approaches were first analyzed mathematically and subsequently compared by means of circuit simulations. It was shown that the proposed approach for the realization of the EFs – i.e. by means of resistors – allows a reduction of the DC power consumption by 19% compared to the current-source approach for an equivalent performance in terms of linearity and bandwidth. Finally, a modulator driver concept suitable for higher-order modulation formats is studied, namely the 8-level pulse amplitude modulation (PAM-8). The circuit was realized as a 3-bit digital-to-analog converter (DAC), thus being able to yield 8-level output signals. Moreover, the circuit is able to function as a PAM-4 driver as well, thanks to the tunable tail currents of the DAC core. It achieves a symbol rate of 50 Gbaud, which corresponds to a bit rate of 150 Gb/s for the PAM-8 modulation and 100 Gb/s for PAM-4. The study showed that a modulator driver can be realized that is able to switch between different modulation formats (namely PAM-8 and PAM-4), without requiring extra power or additional circuit parts. Moreover, the use of on-chip single-to-differential converters (SDCs) targets the relaxation of the requirements on the stages that precede the driver. Finally, relating its DC power consumption (590 mW, including the SDCs) to its output voltage swing (4 Vpp,d), the driver shows one of the highest power efficiencies among PAM modulator drivers in the literature

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

Passive combining network for THz phased arrays

Abstract. Power combiners play an important role in the phased array transceivers at mmWave and THz frequencies. Wilkinson combiner has been in use for a long time and is considered one of the best power combiners due to its good port isolation and low losses. In this work theoretical and simulation studies have been done to design the power combiner for sub-THz receiver front-end in the IHP 130nm SiGe process. The Wilkinson combiner designed in this work is able to provide decent performance around 300GHz frequency and shows good isolation between the input ports. The differential Wilkinson combiner has input combining port isolation of -18.2dB and reflection coefficients are around -8.5±0.5dB. While from the transmission coefficients the path loss observed is around 3.7dB. Besides this the differential Wilkinson combiner has also provided decent performance with the phase shifter testbench

Integrated Circuit Design for Hybrid Optoelectronic Interconnects

This dissertation focuses on high-speed circuit design for the integration of hybrid optoelectronic interconnects. It bridges the gap between electronic circuit design and optical device design by seamlessly incorporating the compact Verilog-A model for optical components into the SPICE-like simulation environment, such as the Cadence design tool. Optical components fabricated in the IME 130nm SOI CMOS process are characterized. Corresponding compact Verilog-A models for Mach-Zehnder modulator (MZM) device are developed. With this approach, electro-optical co-design and hybrid simulation are made possible. The developed optical models are used for analyzing the system-level specifications of an MZM based optoelectronic transceiver link. Link power budgets for NRZ, PAM-4 and PAM-8 signaling modulations are simulated at system-level. The optimal transmitter extinction ratio (ER) is derived based on the required receiver\u27s minimum optical modulation amplitude (OMA). A limiting receiver is fabricated in the IBM 130 nm CMOS process. By side- by-side wire-bonding to a commercial high-speed InGaAs/InP PIN photodiode, we demonstrate that the hybrid optoelectronic limiting receiver can achieve the bit error rate (BER) of 10-12 with a -6.7 dBm sensitivity at 4 Gb/s. A full-rate, 4-channel 29-1 length parallel PRBS is fabricated in the IBM 130 nm SiGe BiCMOS process. Together with a 10 GHz phase locked loop (PLL) designed from system architecture to transistor level design, the PRBS is demonstrated operating at more than 10 Gb/s. Lessons learned from high-speed PCB design, dealing with signal integrity issue regarding to the PCB transmission line are summarized

System-level design and RF front-end implementation for a 3-10ghz multiband-ofdm ultrawideband receiver and built-in testing techniques for analog and rf integrated circuits

This work consists of two main parts: a) Design of a 3-10GHz UltraWideBand (UWB) Receiver and b) Built-In Testing Techniques (BIT) for Analog and RF circuits. The MultiBand OFDM (MB-OFDM) proposal for UWB communications has received significant attention for the implementation of very high data rate (up to 480Mb/s) wireless devices. A wideband LNA with a tunable notch filter, a downconversion quadrature mixer, and the overall radio system-level design are proposed for an 11-band 3.4-10.3GHz direct conversion receiver for MB-OFDM UWB implemented in a 0.25mm BiCMOS process. The packaged IC includes an RF front-end with interference rejection at 5.25GHz, a frequency synthesizer generating 11 carrier tones in quadrature with fast hopping, and a linear phase baseband section with 42dB of gain programmability. The receiver IC mounted on a FR-4 substrate provides a maximum gain of 67-78dB and NF of 5-10dB across all bands while consuming 114mA from a 2.5V supply. Two BIT techniques for analog and RF circuits are developed. The goal is to reduce the test cost by reducing the use of analog instrumentation. An integrated frequency response characterization system with a digital interface is proposed to test the magnitude and phase responses at different nodes of an analog circuit. A complete prototype in CMOS 0.35mm technology employs only 0.3mm2 of area. Its operation is demonstrated by performing frequency response measurements in a range of 1 to 130MHz on 2 analog filters integrated on the same chip. A very compact CMOS RF RMS Detector and a methodology for its use in the built-in measurement of the gain and 1dB compression point of RF circuits are proposed to address the problem of on-chip testing at RF frequencies. The proposed device generates a DC voltage proportional to the RMS voltage amplitude of an RF signal. A design in CMOS 0.35mm technology presents and input capacitance <15fF and occupies and area of 0.03mm2. The application of these two techniques in combination with a loop-back test architecture significantly enhances the testability of a wireless transceiver system

A review of technologies and design techniques of millimeter-wave power amplifiers

his article reviews the state-of-the-art millimeter-wave (mm-wave) power amplifiers (PAs), focusing on broadband design techniques. An overview of the main solid-state technologies is provided, including Si, gallium arsenide (GaAs), GaN, and other III-V materials, and both field-effect and bipolar transistors. The most popular broadband design techniques are introduced, before critically comparing through the most relevant design examples found in the scientific literature. Given the wide breadth of applications that are foreseen to exploit the mm-wave spectrum, this contribution will represent a valuable guide for designers who need a single reference before adventuring in the challenging task of the mm-wave PA design

SiGe BiCMOS 4-bit phase shifter and T/R module for X-band phased arrays

Current phased array RADAR (RAdio Detection And Ranging) systems conventionally employ transmit/receive (T/R) modules implemented in III-V technologies (such as GaAs and InP) and their usage is mainly restricted to military applications. The next generation phased array systems require thousands of T/R modules with lower cost, size and power consumption. Advances in SiGe BiCMOS process technologies make it a viable option for next generation phased array systems, especially for commercial applications. In the light of these trends, this thesis presents the design of a 4-bit SiGe X-band (8-12 GHz) passive phase shifter and the complete SiGe X-band T/R module, realized in IHP 0.25- m SiGe BiCMOS process. The phase shifter is based on switched lter topology, utilizing a low-pass network for phase shift state and isolated NMOS transistors are used for bypass state. It is composed of 22 , 45 and 90 bits and the 180 bit is realized by cascading two 90 bits. The return loss of each bit is better than 10 dB, the overall phase shifter has an average of 14 dB insertion loss. Minimum RMS phase error of 3 is obtained at 10.1 GHz. RMS phase error is better than 11 at 9.2-10.8 GHz band. The overall phase shifter occupies 0.9 mm2 area, has no DC power consumption and achieves input-referred 1-dB compression point of 15 dBm. The integration of a compact T/R module using the 4-bit phase shifter and the previously developed building blocks such as low-noise ampli er (LNA), power ampli er (PA) and single-pole double-throw (SPDT) switches is presented. The developed SiGe X-band T/R module occupies only 4.9 mm2 chip area. In 9-10 GHz band T/R module achieves a measured gain of 10-11.5 dB in receiver mode and 10.7- 12 dB gain in transmitter mode. A minimum RMS phase error of 5 is achieved at 9 GHz. Noise gure in receiver mode is measured between 4-6 dB while the IIP3 is receive mode is measured as -10.5 dB. Output power at 1-dB compression in transmit mode is 16 dBm. These parameters are achieved with a power consumption of 285 mW