Memristors are among emerging technologies with many promising features, which makes them suitable not only for storage purposes but also for computations. In this work, focusing on in-memory computations, we first present our semi-serial IMPLY-based adder and perform an extensive analysis of its merits. In addition to providing a favorable balance between the number of steps and number of memristors, a key property of the presented adder is its compactness as compared to the state-of-the-art adders. Next, using our semi-serial adder, we propose an IMPLY-based multiplier. We show that the proposed multiplier is more than 5x better than other works based on the figure of merit which gives equal weight to the number of steps (i.e., speed) and required die area. Additionally, we provide a deeper insight into IMPLY-based arithmetic units, their properties, design characteristics, and advantages or disadvantages compared to one another by proposing new figures of merit and performing comprehensive comparative analyses. This facilitates the process of design, or selection, of suitable units for the design engineers and researchers in the field.

We present a CMOS computational camera with on-chip compressive sensing technique. Through per-pixel programmable charge modulation, camera exposure is spatial-temporally encoded by a CMOS image sensor without utilization of superfluous optical modulators. Each sensor pixel incorporates a two-tap charge modulator and exposure code memory cells, and a proof-of-concept image sensor (128×128 pixels) is capable of per-frame spatial-temporal coded exposure in either full resolution or designated region of interest. After reconstruction, high-speed videos at various temporal resolutions are recovered, while the prototype camera operates at 10 fps. Comparing to previous works, this camera design provides a power-efficient solution for compressive sensing related applications.

This article presents a 28-GHz power amplifier (PA) suitable for fifth-generation (5G) wireless systems. Designed in a 65-nm bulk CMOS, the PA achieves a saturated output power (Psat) of 23.2 dBm at 28 GHz. The AM-AM and the AM-PM distortion have the overshoot of less than 0.3 dB and 0.2°, respectively, at 28 GHz. The AM-PM variation remains less than 1.9° over the frequency band of 26-31 GHz with a peak power-added efficiency (PAE) of 35.5%. Several techniques, including strategic placement of varactors, a proposed multi-function coplanar-waveguide (CPW)-like power combining structure, and a systematic design approach for the passive networks, are used to improve the efficiency and linearity of the design leading to a negligible difference between P1,dB and Psat. The proposed linearity improvement technique, which uses an adaptive feedback structure to adjust the input impedance of the output stage based on the output power and also direct more current at higher output power levels, enhances the linearity through lowering both AM-AM and AM-PM conversions. The design enables 2.5-GS/s 64-QAM operation at average Pout of 16.1 dBm with an error-vector magnitude/adjacent-channel power ratio (EVM/ACPR) of better than -26.2-dB/-28.32-dBc without using any digital pre-distortion.

In this paper, we present a low-power event-driven receiver intended for miniaturized biomedical implants. The fully integrated system can operate by power harvesting from electromagnetic fields using a radio frequency-to-dc converter or through a 0.5-V voltage supply such as a rechargeable battery. Without any external component and calibration overhead, the proposed double-mixing receiver is operating at a frequency of 915-MHz industrial, scientific, and medical band and is robust to process, supply voltage, and body temperature variations. The proof-of-concept receiver is designed and implemented in a 0.13-μm CMOS technology. The system occupies a silicon area of 0.75 mm² and consumes only 9.1-μW power while achieving a sensitivity of -48 and -39 dBm at the data rate of 1 and 100 kb/s, respectively.

This article presents an event-driven ultralow-power radio intended for miniaturized biomedical implants. In its powerlink, the system employs an RF-to-dc converter to scavenge energy from the electromagnetic waves in the 2.4-GHz unlicensed industrial, scientific, and medical (ISM) band. The bidirectional time-division datalink is realized by exploiting the 915-MHz ISM band, and its operation is coordinated by a smart control module, where the cyclic redundancy check is conducted to switch the system between monitoring and interrogation modes. A proof-of-concept radio is fabricated in a 0.13-μm CMOS process with the chip area of 1.4 mm². Without employing any external components, the radio is robust to process, supply voltage, and body temperature variations, leading to a low-cost and highly integrated wireless solution. During the monitoring mode, the downlink data reception and demodulation are realized by a receiver that consumes 27.5 μW while achieving a sensitivity of -69 and -59 dBm at the data rates of 1 and 100 kb/s, respectively. Dissipating peak power of 49.5 μW in the interrogation mode, the data transmitter delivers an output power of -30.6 dBm with a data rate of 2.5 Mb/s.

Water treatment is the most concerned research area as it is closely related to the quality of human life. Capacitive de-ionization (CDI) has become a popular desalination technique for water treatment in recent years; however, transferring CDI technology to practice industrial applications face many problems due to the lack of experience and ability of monitoring on its operation status. Thus, in this article, a novel self-powered smart monitoring platform (SMP) is codesigned with a laboratory-scale CDI cell by providing regulated polarized voltage to prevent faradaic reactions and to evaluate CDI's performance using desalination metrics. The proof-of-concept SMP can acquire sensory data and wirelessly transmit information to the reader by radio-frequency identification (RFID) technique. A laboratory-scale CDI cell is fabricated in house by the cost-effective carbon electrodes with high electrochemical stability. Experiments are conducted to evaluate the function of the system on real-time monitoring of the CDI cell for their conductivity, salt absorption, and charge efficiency. The measurement results demonstrate that the proposed prototype is effective in terms of supplying, monitoring, and diagnosing the operation condition of the CDI cell. Furthermore, the proof-of-concept SMP developed for the CDI reactor can achieve up to 8.8-m communication distance, while consuming 402.6 μW active power during operation. Therefore, it is a suitable choice for low-power and low-cost wireless sensor network.