Tuan Anh Vu

UWB Vivaldi antenna for impulse radio beamforming

In this paper, two different types of Vivaldi antenna are designed and tested suitable for electromagnetic beamforming. The first is an antipodal Vivaldi antenna, while the other is a tapered slot Vivaldi antenna. They are both ultra wideband antennas for the 1 GHz to 5 GHz frequency band. They have low impulse distortion and the voltage standing wave ratio (VSWR) less than 2 throughout the entire bandwidth. The antennas are used for impulse radio beamforming.

An inductorless 3–5 GHz band-pass filter with tunable center frequency in 90 nm CMOS

A novel inductorless tunable switched-capacitor band-pass filter based on N-path periodically time-variant networks is presented. The proposed UWB band-pass filter is complete with ring-oscillator used for multi-phase clock generation suitable for power-efficient IR-UWB systems. The filter prototype was fabricated in TSMC 90 nm CMOS, and occupies a chip area of 0.004 mm2. It archives a -3 dB bandwidth of 2 GHz while the center frequency can be tuned from 4 GHz to 4.4 GHz. Power consumption is 1.1 mW from 1.2 V supply voltage, and the performance was verified experimentally.

A variable-gain single-bit ultra-wideband quantizer for baseband receiver front-end

This paper presents a novel variable-gain single-bit ultra-wideband (UWB) quantizer suitable for baseband receiver front-end fabricated in 90 nm CMOS technology. The prototype chip is tested, and measurement results are provided. The proposed quantizer achieves a -3 dB bandwidth covering a spectrum from 10 MHz to 2.7 GHz. The overall gain can be varied from 23 dB to 33 dB while the noise figure (NF) is between 7 dB and 10 dB. The quantizer core occupies a die area of 0.25 × 0.17 mm2 and consumes 4.8 mW from a 1.2 V supply voltage.

A 3–5 GHz IR-UWB receiver front-end for wireless sensor networks

This paper presents a impulse-radio ultra-wideband (IR-UWB) receiver front-end covering the frequency band of 3-5 GHz intended for low power, low data-rate communication over a relative short range for such applications like wireless sensor networks (WSNs). The receiver front-end was designed and verified in 90 nm CMOS provided by TSMC. It employs direct-conversion (homodyne) architecture, and occupies a chip area of 0.9 mm2. The receiver exhibits a peak gain of 45 dB at 4 GHz, and consumes a total power of 26.6 mW from a 1.2 V supply voltage. Input return loss, S11 ≤ -12 dB, and noise figure (NF) is between 8 dB and 9 dB through 3-5 GHz bandwidth.

Continuous-time symbol detector for IR-UWB rake receiver in 90 nm CMOS

In this paper, a coherent continuous-time symbol detector suitable for a simple RAKE receiver using single-bit correlation is reported. A working chip with fully integrated digital symbol detection without any clocks, ADC and filters for simple and power efficient CMOS implementation has been presented. Cross-correlating RAKE receiver with on-off keying is the most challenging receiver due to its hardware implementation complexity. Also process variations in 90 nm CMOS technology impose significant design challenges to the delayline. Optimal design of the delay elements and the use of pulse width controller blocks (PWC) along the delayline allows narrow pulses through the system significantly reducing the process variation impact. The optimized delayline combined with the high-speed counter and the match thresholder constitute a complete continuous-time IR-UWB RAKE receiver. With a data rate of 1.5 Mbit/s and a power consumption of 2.36 mW, operation of the symbol detector in continuous-time is verified with measured results. The symbol detector along with the ranging system in a master-slave configuration can estimate time-of-flight (ToF) value which aids localization.

An inductorless 6-Path band-pass filter with tunable center frequency for UWB applications

This paper presents an inductorless switched-capacitor 6-path band-pass filter suitable for impulse radio ultrawideband (IR-UWB) application designed in nanometer CMOS technology. The proposed wideband band-pass filter is working in discrete-time intended for power-efficient IR-UWB systems. In 90 nm CMOS we were able to design a filter with -3 dB bandwidth of 2.5 GHz and a center frequency tunable from 4.1 GHz to 4.5 GHz. Estimated power consumption is 35 mW from 1.2 V supply voltage according to post-layout simulation. A novel ring oscillator based multiphase clock is proposed, enabling center-frequency tuning at microwave frequencies.

A continuous-time differential single-bit quantizer for IR-UWB receivers

In this paper, we propose a continuous-time differential single-bit quantizer intended for impulse radio ultrawideband (IR-UWB) receivers. It exploits an active balun at the input to obtain single-ended to differential conversion. The quantizer prototype was fabricated in 90 nm CMOS and occupies a chip area of 0.09 mm2. The proposed quantizer achieves a -3 dB bandwidth of 2.4 GHz with a high differential gain of approximately 35 dB and a sensitivity of 40 mV at 2 GHz. Power consumption is 13.1 mW from 1.2 V supply voltage and the performance was verified experimentally.

A 70-dB, 3.1–10.6-GHz CMOS amplifier in low-power 90 nm CMOS

This paper presents a novel high-gain CMOS amplifier suitable for ultra-wideband (UWB) applications. The proposed amplifier achieves a -3 dB bandwidth covering the entire FCC UWB spectrum from 3.1 GHz to 10.6 GHz with a very high gain of approximately 70 dB. The amplifier is an area-efficient, single-inductor solution designed for TSMC 90 nm CMOS low-power process while consuming 25.1 mW from 1.2 V supply voltage.

An ultra-wideband, continuous-time, differential, single-bit quantizer in 90 nm CMOS

In this paper, we propose an ultra-wideband, differential, single-bit quantizer intended for impulse radio, ultra-wideband (IR-UWB) applications using standard 90 nm TSMC digital CMOS technology. The proposed quantizer is working in continuous-time for power-efficient IR-UWB implementations with a 5 GHz bandwidth and a very high differential gain of approximately 70 dB while consuming 33.5 mW from 1.2 V supply voltage. Coupled inductors are explored for bandwidth extension and post-layout simulated results are provided.

Electromagnetic impulse radio camera

An UWB impulse radio programmable transmitter array is presented, usable for electromagnetic beamforming. The linear antenna array may be programmed for focal beamforming using seven impulse radio transmitters. Two different spatial configurations are evaluated for use as beam scanning electronics of an electromagnetic camera. A novel high-precision, programmable delay element is explored for accurate beam control. Measured results shows that the scan line of the beamformer can be steered with sufficient resolution facilitating an electromagnetic CMOS camera.