Taiyun Chi

A Multi-Modality CMOS Sensor Array for Cell-Based Assay and Drug Screening

In this paper, we present a fully integrated multi-modality CMOS cellular sensor array with four sensing modalities to characterize different cell physiological responses, including extracellular voltage recording, cellular impedance mapping, optical detection with shadow imaging and bioluminescence sensing, and thermal monitoring. The sensor array consists of nine parallel pixel groups and nine corresponding signal conditioning blocks. Each pixel group comprises one temperature sensor and 16 tri-modality sensor pixels, while each tri-modality sensor pixel can be independently configured for extracellular voltage recording, cellular impedance measurement (voltage excitation/current sensing), and optical detection. This sensor array supports multi-modality cellular sensing at the pixel level, which enables holistic cell characterization and joint-modality physiological monitoring on the same cellular sample with a pixel resolution of 80 μm×100 μm. Comprehensive biological experiments with different living cell samples demonstrate the functionality and benefit of the proposed multi-modality sensing in cell-based assay and drug screening.

A Multi-Phase Sub-Harmonic Injection Locking Technique for Bandwidth Extension in Silicon-Based THz Signal Generation

This paper presents a multi-phase sub-harmonic injection locking technique to significantly extend the locking range of a multi-phase injection locking oscillator (ILO). Leveraging this technique, a scalable and cascadable “active frequency multiplier” chain architecture is proposed, which achieves THz signal generation from a low mm-wave frequency tone. We also propose a multi-ring topology to facilitate the design and the high-frequency routing. As a proof-of-concept, a cascaded 3-stage 3-phase 2nd-order sub-harmonic ILO chain is implemented in a SiGe BiCMOS process. It achieves 504 GHz signal generation from a 42 GHz tone with a 4.4% frequency tuning range, which is the largest tuning range among all the reported Si-based THz harmonic oscillator sources at the 0.5 THz band.

An ultra-broadband compact mm-wave butler matrix in CMOS for array-based MIMO systems

This paper presents the design scheme of an ultra-broadband compact mm-wave Butler Matrix. The design employs new transformer-based swapped-port couplers and lumped LC-based π-network phase shifters to achieve an extremely compact chip size and ultra-broad bandwidth. This scheme is implemented as a 4×4 Butler Matrix in a standard 65nm CMOS technology with a core area of 0.335×0.215 mm2 and a broad bandwidth of 9.8 GHz with the center frequency of 63 GHz. This Butler Matrix design also achieves small insertion loss of 2.77 dB and high-quality matching among the ports with less than 0.6 dB amplitude mismatch and less than 5° phase imbalance at 63 GHz. Based on the measured S-parameters, the four concurrent electrical array patterns of the Butler Matrix achieve its array peak-to-null ratio of better than 17dB between 57 GHz and 67 GHz.

A multi-feed antenna for antenna-level power combining

This paper proposes a multi-feed antenna structure that synthesizes the desired radiation characteristics with antenna-level power combining. Compared with an antenna array that spatially combines the radiation E-field and H-field at the far-field, the proposed multi-feed antenna combines the radiation power from different feeds directly on the antenna. Such a unique structure occupies a much smaller footprint and offers the flexibility to optimize the antenna driving impedances based on the locations of the antenna feeds. As two proof-of-concept designs, a two-feed 0.5λ slot antenna and a three-feed 0.7λ slot antenna with the input feeding networks are designed at 10.3GHz. A conventional single-feed 0.5λ slot antenna and a single-feed 0.7λ slot antenna are also implemented as the reference designs. Well matched radiation patterns between the proposed multi-feed antennas and the conventional single-feed antennas are observed, demonstrating the antenna-level power combining capability of the proposed multi-feed antennas.

A fully packaged D-band MIMO transmitter using high-density flip-chip interconnects on LCP substrate

In this paper, a fully packaged D-band MIMO phased-array transmitter using system-on-package (SoP) technology is presented. The transmitter chip is implemented in a 32nm CMOS SOI process and assembled on the liquid crystal polymer (LCP) substrate by flip-chip interconnects. The MIMO operation is enabled by an on-chip transformer based 4×4 Butler Matrix. The package fabrication realizes a consistent minimum feature size of 20μm on a 2-mil flexible LCP substrate. Moreover, the CMOS chip with a total of 72 RF and DC pads is well aligned with and successfully bonded onto the corresponding patterns on the LCP package. The capability of package fabrication with fine features and high-density chip-to-package interconnections enables the implementation of cost-effective and high-performance hybrid complex systems at mm-wave. Measurement results based on probing demonstrate the functionalities of the entire system.

11.7 A multimodality CMOS sensor array for cell-based assay and drug screening

Cell-based assays are powerful tools to characterize cell- or tissue-specific physiological behaviors under external biochemical stimuli. External biochemical stimuli trigger endogenous cellular mechanisms that produce a cascade of physiological changes, resulting in easily measurable signals. Cell-based assays are widely used for large-scale drug screening in the pharmaceutical industry, where in vitro cultured cells are used to characterize the potency and toxicity of thousands of chemicals, leading to new drug development. This is particularly relevant in individualized medicine as patient-derived cells can test personalized drug responses. However, most current cell-based assays are conducted on single-modality sensors (electrical or optical only), which cannot capture the complexity of multi-parameter physiological responses. Sequentially transporting cell samples through different sensor platforms results in low throughput and potential abrogation of cell functions, while parallel monitoring of multiple samples with different modalities is subject to cell-to-cell variation even in a homogeneous cell population.

A D-band (110 to 170 GHz) SPDT switch in 32 nm CMOS SOI

This work demonstrates the implementation of a D-band single-pole double-throw switch(SPDT) in 32 nm CMOS SOI technology. A tuned shunt topology is used to achieve the lowest insertion loss. The switch demonstrates state-of-the art performance showing an insertion loss of 2.6 dB at 140 GHz and good matching across the whole D-band. Measurements also show high isolation of greater than 20 dB from 110 to 170 GHz. This is the lowest insertion loss of an SPDT switch that has been designed for the D-band and reported in a 32 nm CMOS SOI process.

17.3 A 60GHz on-chip linear radiator with single-element 27.9dBm P sat and 33.1dBm peak EIRP using multifeed antenna for direct on-antenna power combining

A major challenge for low-cost silicon-based mm-wave wireless links, e.g., for the 5G communication, is to provide large transmitter (Tx) output power (Pout) with high energy efficiency and linearity from a limited supply voltage, so that the high path loss and limited link budget at mm-wave can be compensated. Power combining is often required for high-power mm-wave Tx. The existing power-combining techniques are mainly in two categories. Passive on-chip/on-package networks can combine Pout from multiple power amplifiers (PAs) and feed a single antenna port [1–4]. However, lossy power combiners and large impedance transformation ratios degrade the total Pout delivered to the antenna and lower the Tx efficiency. Alternatively, spatial power combining using antenna array increases the total EIRP but at the expense of a large array-panel size. Moreover, a large antenna array often presents an exceedingly narrow (or even pencil-sharp) beamwidth; this complicates the Tx/Rx alignment and is challenging for dynamic and mobile mm-wave applications, such as 5G links. In addition, adding silicon lens enhances EIRP but increases cost and packaging complexity.

A Millimeter-Wave Dual-Feed Square Loop Antenna for 5G Communications

A millimeter-wave (mm-Wave) dual-feed square loop antenna is presented in this paper for 5G communications. It synthesizes identical far-field radiation patterns as a conventional single-feed square loop antenna. The dual-feed antenna (DFA) also simplifies or even eliminates the lossy power-combining network between the transmitter and antenna, achieving direct on-antenna power combining. The proposed antenna concept significantly improves the total radiated power and power efficiency of a wireless transmitter, particularly useful for 5G transmitters that normally require large output power to compensate the high mm-Wave path loss. Compared with antenna-array-based spatial power combining, the DFA only requires a single-antenna footprint and maintains the single-element beamwidth, ideal for mobile 5G communications. The dual-feed square loop antenna is designed and characterized at two potential 5G bands, i.e., 38.5 and 73.5 GHz. Conventional single-feed square loop antennas are implemented as reference designs. Closely matched antenna characteristics are achieved in measurement between the proposed DFA and conventional single-feed antenna. The dual-feed square loop antenna has measured broadside gain of 2.9 and 3 dBi, and fractional bandwidth of 13% and 14%, at 38.5 and 73.5 GHz, respectively. High-speed modulation test is also performed. A 4.3% error vector magnitude (EVM) with a −33.2-dBc adjacent channel leakage ratio (ACLR) for 6-Gb/s 64QAM is achieved at 38.5 GHz, and a 5.6% EVM with a −33.4-dBc ACLR for 6-Gb/s 64QAM is measured at 73.5 GHz, which demonstrates the viability of the proposed DFA for high-speed and complex modulations required by 5G communications.

A 5GHz all-passive negative feedback network for RF front-end self-steering beam-forming with zero DC power consumption

This paper presents an all-passive negative feedback network to perform autonomous RF front-end beam-forming towards the direction of the incident RF beam. The beam-forming front-end block consists of a passive network for RF signal processing, voltage rectifiers, and voltage-controlled phase shifters, all of which are passive components and consume zero DC power. A proof-of-concept 4-element self-steering beam-forming block at 5GHz is implemented in a standard 130nm CMOS process and occupies an area of 4.1mm2. The measurements demonstrate that a high-quality 4-element array factor is successfully synthesized for the input progressive phase shift from -120° to +120°. At an input power Pin of -17dBm/element, the normalized array factor is -4.3dB/-3.2dB at +90°/-90° input progressive phase shift in the closed-loop operation, out-performing reported active self-steering beam-formers. To the best of our knowledge, this is the first demonstration of an all-passive network for front-end self-steering beam-forming with zero DC power.