Muhammad Arsalan

Wireless Dosimeter: System-on-Chip Versus System-in-Package for Biomedical and Space Applications

A new floating-gate (FG) MOSFET based wireless dosimeter system-in-package (SiP) is presented. This miniature and completely integrated wireless dosimeter SiP comprises a CMOS FG radiation sensor and transmitter (TX) in a low-temperature co-fired ceramic (LTCC) package. The design is very well suited to wireless transmission of radiation sensor data in radiotherapy and to Extra Vehicular Activity Radiation Monitoring (EVARM) in space. Two different solutions, namely system-on-chip (SoC) and SiP, are demonstrated. In the SoC, which is size and power efficient, the TX includes an on-chip loop antenna which also acts as the inductor for the VCO resonant tank circuit. The SiP solution has an LTCC antenna with optimized impedance to conjugate match the TX chip. The radiation sensor demonstrates a measured sensitivity of 5 mV/rad. The SoC module size is only 2 mm2, consumes 5.3 mW of power and delivers -0.9 dBm of radiated power, sufficient to communicate with a low noise receiver connected to an off-chip patch antenna placed 1.38 m away. The SiP design provides a larger communication range of 75 m at the cost of additional power consumption and size.

Charge-recovery power clock generators for adiabatic logic circuits

To get maximum energy efficiency from adiabatic logic circuits several charge-recovery power clock generators (PCGs) have been published in recent years. This paper compares and analyzes the performance and energy efficiency of various PCGs in a uniform test environment. The test benches are laid out in a standard 0.18 /spl mu/m CMOS technology and the results are mainly based on post layout simulations.

On-Chip Implantable Antennas for Wireless Power and Data Transfer in a Glaucoma-Monitoring SoC

For the first time, separate transmit and receive on-chip antennas have been designed in an eye environment for implantable intraocular pressure monitoring application. The miniaturized antennas fit on a 1.4-mm 3 CMOS (0.18 μm) chip with the rest of the circuitry. A 5.2-GHz novel inductive-fed and loaded receive monopole antenna is used for wirelessly powering the chip and is conjugately matched to the rectifier in the energy-harvesting and storage unit. The 2.4-GHz transmit antenna is an octagonal loop that also acts as the inductor of the voltage control oscillator resonant tank. To emulate the eye environment in measurements, a custom test setup is developed that comprises Plexiglass cavities filled with saline solution. A transition, employing a balun, is also designed, which transforms the differential impedance of on-chip antennas immersed in saline solution to a 50-Ω single-ended microstrip line. The antennas on a lossy Si substrate and eye environment provide sufficient gain to establish wireless communication with an external reader placed a few centimeters away from the eye.

A Fully Differential Monolithic LNA With On-Chip Antenna for a Short Range Wireless Receiver

This letter presents the smallest reported 5 GHz receiver chip (1.3 mm2) with an on-chip antenna in standard 0.13 mum CMOS process. The miniaturization is achieved by placing the circuits inside a meandered antenna. The on-chip antenna is conjugately matched to the low noise amplifier (LNA) over a wide frequency range. The design methodology for co-design of the on-chip antenna and LNA is described. The LNA is completely differential, consumes only 8 mW of power and provides a gain of 21 dB. Design tradeoffs and measurement challenges are given.

Asynchronous Adiabatic Logic

Power clock generators (PCGs) are the prevalent overhead for the adiabatic systems and mutilate all the low-power advantage from the adiabatic logic part by consuming a large portion of the total power in the clock generation circuitry (Arsalan and Shams, 2005). In addition to the PCG issues, routing multiple clock phases for adiabatic circuits is not very convenient and raises a number of cost, performance and viability issues. To get rid of the problems related to clock generation and synchronous clock routing, a new solution namely asynchronous adiabatic logic (AAL) is proposed to combing the benefits of the adiabatic logic circuits with that of asynchronous logic systems. Going asynchronous not only eliminates the need of PCGs, hence all the problems associated with the generation and routing of the clocks, it also bring all the advantages intrinsically associated with an asynchronous design such as low power and reliable logical operation.

7.9 pJ/Step Energy-Efficient Multi-Slope 13-bit Capacitance-to-Digital Converter

In this brief, an energy-efficient capacitance-to-digital converter (CDC) is presented. The proposed CDC uses digitally controlled coarse-fine multi-slope integration to digitize a wide range of capacitance in short conversion time. Both integration current and frequency are scaled, which leads to significant improvement in the energy efficiency of both analog and digital circuitry. Mathematical analysis for circuit nonidealities, noise, and improvement in energy efficiency is provided. A prototype fabricated in a 0.35-μm CMOS process occupies 0.09 mm2 and consumes a total of 153 μA from 3.3 V supply while achieving 13-bit resolution. The operation of the prototype is experimentally verified using MEMS capacitive pressure sensor. Compared to recently published work, the prototype achieves an excellent energy efficiency of 7.9 pJ/Step.

A 5.2GHz, 0.5mW RF powered wireless sensor with dual on-chip antennas for implantable intraocular pressure monitoring

For the first time a single chip implantable wireless sensor system for Intraocular Pressure Monitoring (IOPM) is presented. This system-on-chip (SoC) is battery-free and harvests energy from incoming RF signals. The chip is self-contained and does not require external components or bond wires to function. This 1.4mm3 SoC has separate 2.4GHz-transmit and 5.2GHz-receive antennas, an energy harvesting module, a temperature sensor, a 7-bit TIQ Flash ADC, a 4-bit RFID, a power management and control unit, and a VCO transmitter. The chip is fabricated in a standard 6-metal 0.18μm CMOS process and is designed to work with a post-processed MEMS pressure sensor. It consumes 513μW of peak power and when implanted inside the eye, it is designed to communicate with an external reader using on-off keying (OOK).

Ultra Low Power CMOS-Based Sensor for On-Body Radiation Dose Measurements

For the first time, a dosimeter employing two floating gate radiation field effect transistors (FGRADFET) and operating at mere 0.1 V is presented. The novel dosimeter requires no power during irradiation and consumes only 1 during readout. Besides the low power operation, structural changes at the device level have enhanced the sensitivity of the dosimeter considerably as compared to previous designs. The dosimeter is integrated with a wireless transmitter chip, thus eliminating all unwanted communication and power cables. It has been realized monolithically in DALSAs 0.8 complementary metal-oxide-semiconductor process and characterized with X-ray and γ-ray sources. A maximum sensitivity of 5 mV/rad for X-rays and 1.1 mV/rad for -rays have been achieved in measurements. Due to its small size, low-power, and wireless operation, the design is highly suitable for miniaturized, wearable, and battery operated dosimeters intended for radiotherapy and space applications.

A robust parasitic-insensitive successive approximation capacitance-to-digital converter

In this paper, we present a capacitive sensor digital interface circuit using true capacitance-domain successive approximation that is independent of supply voltage. Robust operation is achieved by using a charge amplifier stage and multiple comparison technique. The interface circuit is insensitive to parasitic capacitances, offset voltages, and charge injection, and is not prone to noise coupling. The proposed design achieves very low temperature sensitivity of 25ppm/°C. A coarse-fine programmable capacitance array allows digitizing a wide capacitance range of 16pF with 12.5-bit quantization limited resolution in a compact area of 0.07mm2. The fabricated prototype is experimentally verified using on-chip sensor and off-chip MEMS capacitive pressure sensor.

Low Cost and Pipe Conformable Microwave-Based Water-Cut Sensor

Efficient oil production and refining processes require the precise measurement of water content in oil. This paper presents a novel planar microwave sensor for entirely non-intrusive in situ water cut (WC) sensing over the full range of operation, i.e., 0%-100%. A planar configuration has enabled the direct implementation of WC sensor on the pipe surface using low cost method, i.e., screen printing using 3D printed mask. Modified ground plane-based T-resonator design makes this WC sensor usable for the wide range of pipe sizes present in the oil industry. The viability of this sensor has been confirmed through electromagnetic simulations as well as through a prototype characterization. Two cases of oil and water mixtures, namely, separate phases and homogeneous mix, have been studied. Measurements performed over two independently built prototypes show the root mean square variation in results of only 0.1%.