Giuseppe Coviello

Distributed amplifier design for UWB positioning systems using the gm over id methodology

In this paper we exploit the gm over ID methodology to optimize the design of a four stage conventional Distributed Amplifier (DA) for an Ultra-Wide Band positioning system. The W/L ratio and the DC-biasing of the amplifiers transistors are determined according to the gm over ID methodology by using a series of lookup tables generated starting from the model of the devices. The DA was designed using the IHP 0.13 μm SiGe process and provides a 14 dB gain over a bandwidth of 10.6 GHz. The input/output return loss of the amplifier is lower than -17 dB over the entire bandwidth, with an average noise figure of 1.95 dB and a 26 mW DC-power consumption.

A 2-GS/s 0.35μm SiGe track-and-hold amplifier with 7-GHz analog bandwidth using a novel input buffer

In this paper a Track-and-Hold amplifier (THA), designed in a low cost 0.35μm SiGe 60GHz technology, suitable for SDR applications, is presented. With the implementation of a novel input buffer, the circuit shows a 3dB bandwidth of 7GHz and a distortion better than 50dB up to, about, that frequency during Track phase. Simulations show a THD better than 50dB up to a frequency of 5.77GHz at 2GS/s and a “reconstructed” 3dB full power bandwidth (FPBW) of 5.86GHz. The circuit draws about 220mA from 3.3V supply, considering all the sampling stage, the output buffer and clock driver.

A 2.5-GS/s 62dB THD SiGe Track-and-Hold Amplifier with feedthrough cancellation technique

In this paper a Track-and-Hold Amplifier (THA), designed in a low cost 0.35μm SiGe 60GHz technology is presented. Thanks to the joint action of a novel input buffer and a suppression feedthrough architecture, it is able to guarantee 62dB Total Harmonic Distortion(THD) up to a frequency of 2.2GHz with 0.9Vp-p differential input at a sampling rate (Fs) of 2.5GS/s. The THA core draws about 145mA from 3.5V supply.

Gm over ID design for UWB distributed amplifier

This paper presents the optimized design of a conventional four-stage distributed amplifier for Ultra-Wide Band applications (UWB). The design flow exploits the gm/ID methodology in order to optimize the size of the transistors to achieve the best tradeoff between gain, input/output matching, noise figure and power DC consumption. The circuit was designed using a 0.13 μm process from IHP Microelectronics, it exhibits a gain of 11 dB over the frequency range from 3.1 to 10.6 GHz and an average noise figure of 2.65 dB. The input/output return loss are lower than 16 dB and the amplifier dissipates only 26 mW with 1.2 V supply. Finally, the chip measures only 1.07 mm × 0.7 mm.

A high precision phase control unit for DDS-based PLLs for 2.4-GHz ISM band applications

This paper introduces the design and implementation of a new programmable phase control unit (PCU) topology for active phased array antennas. The array is based on a hybrid direct digital synthesizer (DDS) phase-lock-loop (PLL) approach. The PCU generates up to 1024 phase shift values programmable in the form of phase-offset words by either a microcontroller or a DSP. As a result a 360° phase shifting range can be scanned in 0.35° tuning steps, which correspond to a beam steering resolution smaller than about 0.5°. Experimental results obtained through the fabrication of a prototype validate the potential of the proposed architecture, and are in good agreement with both simulation and theoretical analysis. The phase shifter is designed and demonstrated across the 2.4-GHz industrial-scientific-medical (ISM) band.

A high bandwidth 11-bit 1.5GS/s track and hold amplifier in 0.25 µm SiGe BiCMOS

The paper describes a Track and Hold Amplifier suitable for high-speed and high resolution applications like Software Defined Radios. Thanks to the adopted techniques to maximize the resolution without reducing the sampling frequency, all the non idealities limiting the equivalent number of bits have been taken into account. In particular a novel technique to reduce the third harmonic distortion has been proposed and exploited. Post-layout simulations show that the performances are quite constant and the linearity is compatible with 11-bit (SFDR) at Fs= 1.5GS/s up to a frequency 1GHz.

A 11-bit Track and Hold Amplifier in 0.25 µm SiGe BiCMOS for RF sampling receivers

The paper describes a Track and Hold Amplifier (THA) suitable for RF sampling and Software Defined Radio receivers where high speed and high resolution are required. The reported THA is based on two main techniques: one for minimizing the differential droop rate and one for improving the HD3 in track mode. Measurements results show that the adopted solutions are both effective. In the desired input band around 1GHz, at the desired sub-sampling frequency (0.5GS/s) the THA provides a linearity compatible with 12-bit (Spurious Free Dynamic Range, SFDR). Moreover at the maximum achievable sampling frequency (1.5GS/s) the performances are quite constant and the resolution is compatible with 11-bit (SFDR) up to an input frequency of 1GHz.

Narrowband distance evaluation technique for indoor positioning systems based on Zadoff-Chu sequences

A rugged method for distance estimation based on an OFDM signal combined with the Zadoff-Chu sequences is introduced. A software algorithm extracts a coarse distance in time domain exploiting the Zadoff-Chu properties. The distance, then, is fine adjusted evaluating the time offset from the subcarriers phase. Several tests were performed in laboratory considering a very harsh indoor environment and using a pair of Right-Hand circularly polarized helical antennas in order to demonstrate the technique effectiveness. The system is able to estimate the distance with a very good level of precision and accuracy with only 50 MHz of signal bandwidth. In fact, the results show a maximum error of 1.23 cm, in distance estimation, and a maximum standard deviation of 0.8 cm. The proposed technique can be used in the implementation of indoor positioning systems.

A novel distance measurement technique for indoor positioning systems based on Zadoff-Chu Sequences

A novel method for distance estimation is introduced, based on an OFDM signal combined with the Zadoff-Chu Sequences. By exploiting the properties of these sequences it is possible to evaluate the distance between a transmitter and a receiver with a very good precision and accuracy. The technique effectiveness is demonstrated in a real operating environment by measuring the distance between two active devices and using a pair of Right-Hand circularly polarized helical antennas, achieving a mean final error of 2.94 cm and a mean standard deviation of 0.95 cm with only 20 MHz of bandwidth. The proposed technique can be used in the implementation of indoor positioning systems.

A systematic design approach for nanoscale inductor-less regulated cascode stages

This paper presents a framework for the systematic design of inductor-less regulated cascode (RGC) stages. Targeting high-speed fiber optic data receiver front-ends, the technique reported combines the symbolic solution of the small-signal model of the RGC and the use of gm/ID based lookup tables to efficiently explore and optimize the resulting design space. A practical design is discussed and implemented in a 180 nm six-metal-layer CMOS process with 1.8V supply. The accuracy and viability of the proposed approach is validated through circuit simulation.