Patrick Garrec

Sense and avoid radar using Data Fusion with other sensors

UAV (Unmanned Aerial Vehicle) are employed in crisis or war times. For training purposes, they must be flown in special areas called “segregated areas”. In the future, both for emerging civilian applications and for training purposes, UAV will have to be inserted into the general Air traffic. So, UAV will have to be equipped with “Sense and Avoid” systems. An interesting solution is to merge a co-operative sensor like ADS-B and a non-cooperative “all weather” one, namely Radar. In favorable cases, the Radar measurements can be improved by using additional Electro-Optical sensors, for instance video sensors.

A 65-nm CMOS DAC Based on a Differentiating Arbitrary Waveform Generator Architecture for 5G Handset Transmitter

The data rate expected for the forthcoming 5G standard induces stringent constraints for handset transceivers. Wideband carrier aggregation will be handled with flexible and low-power architectures implemented in low-cost technologies. An architecture of a wideband signal generator intended to target sub-6-GHz 5G transmission requirements is presented. The architecture is based on a differential pulse code modulation coding scheme and a custom integrating DAC named the Riemann pump. It performs a 9-dB improvement of the signal-to-noise ratio per doubling of the oversampling ratio while ensuring a flat quantization noise floor over the whole multigigahertz conversion band. Its inherent ability to generate synchronous signals allows us to address carrier aggregation purposes; the generation of 10 synchronized 64-QAM modulated signals between 1.8 and 3.6 GHz is simulated. Postlayout simulations of the Riemann pump implemented in 65-nm CMOS technology fit the exposed theoretical features with a submilliwatt-level power consumption.

A Broadband 4.5–15.5-GHz SiGe Power Amplifier With 25.5-dBm Peak Saturated Output Power and 28.7% Maximum PAE

This paper presents the design of a broadband power amplifier (PA) in 130-nm SiGe BiCMOS technology. First, a single-stage broadband single-cell PA covering the 4.5-18-GHz frequency band is introduced. In this frequency range, this single cell achieves a measured gain, saturated output power ( Psat), output 1-dB compression point ( P1dB), and power-added efficiency (PAE) in the range from 12.8 to 15.7 dB, 18.8 to 23.7 dBm, 16.7 to 19.5 dBm, and 11.4 to 31.9%, respectively. Its peak saturated output power and maximum PAE are both obtained at 8.5 GHz. Second, to increase the output power, a PA consisting of two parallel broadband cells with a power combination is presented. This PA operates in the 4.5-15.5-GHz frequency range with measured gain, Psat, P1dB, and PAE in the range from 11 to 16.6 dB, 21.3 to 25.5 dBm, 18.7 to 21.7 dBm, and 11.9 to 28.7%, respectively. It achieves its peak saturated output power of 25.5 dBm at 8.5 GHz and its maximum PAE of 28.7% with an associated output power of 23.6 dBm at 6.5 GHz. Each of those two PAs achieves better performances than the state-of-the-art in broadband SiGe technology when comparing the output power level and efficiency.

The Riemann pump: A concurrent transmitter in GaN technology

An original arbitrary waveform generator (AWG) architecture suited for software radio (SR) transmission is presented. A piecewise linear approximation of the wanted signal is generated thanks to a predefined set of slopes. The digital-to-analog (DA) conversion involved in this operation is based on a differential digital coding which drives a custom digital-to-analog converter (DAC), named here the Riemann Pump. This circuit is in charge of outputting the piecewise linear signal by integration of current steps into a capacitive load, potentially being the input impedance of a power amplifier. Simulations have been carried out on a first design, developed in a GaN technology, with a configuration that covers 1 GHz bandwidth with an oversampling ratio (OSR) of 4 and 3 input bits. The generation of concurrent modulated signals is demonstrated, with a rejection of 30 dBr over the whole band. The system exhibits promising performances as for the realization of a multi-standard concurrent radio frequency transmitter with moderate hardware complexity.

MIMO radar for sense and avoid for UAV

UAV are easily deployable platforms. Up to now they carry payloads (surveillance, combat) for military purposes in crisis or war time. For training, UAV are flown in special areas attributed in a limited space and a limited time slot. In the future, UAV will also be used for civilian tasks. For these reasons, UAV will have to be inserted in the general Air traffic and “Sense and Avoid” systems will be mandatory. Among the possible sensors, the radar is the most pertinent one: it is “all-weather” and provides accurate range, direction and closing speed. In this paper, a low cost solution based on the coherent “MIMO” principles is described. This solution allows the location of the radar within the UAV airframe without any moving parts, hence provides a high reliability level. The rationale of the proposed architecture is explained, then the enabling technologies and related waveforms are described.

An ultra wide band analog-to-digital converter based on a delta-riemann architecture

Wireless telecommunication network requires the use of new frequency bands to increase the data rate. The upcoming 5G standard will address in its lower band (sub 6GHz) at least 10 aggregated LTE carriers with 64 to 256QAM modulation scheme. Whether those bands are high in frequency, 20MHz wide and spread over several GHz, the analog-to-digital conversion becomes a critical technical bottleneck for any ultra low power receivers. Challenges are to convert simultaneously with a complete synchronization all the various bands while keeping in mind constraints of RFIC dedicated for mobile terminals. This paper presents a disruptive architecture of an analog-to- digital converter based on a delta quantization with a closed-loop including a Riemann Pump. A system overview is proposed with behavioural simulations results in MatLab and VHDL-AMS. A prospective of integration in 28nm CMOS technology will target a direct application for sub-6GHz 5G standard with a 4-bit resolution for a frequency range from 1.8 to 3.6 GHz.

A compact fully integrated GaN high power amplifier for C-X band applications

A fully integrated two-stage power amplifier is described for 4-6 W saturated output power over a 4GHz to 11GHz frequency range. The PA topology is chosen to obtain the best bandwidth, output power and Power Added Efficiency (PAE). The output stage is composed of two unit power cells and the power recombination is made by a stacked balun. The differential input of the power stage is provided by the first stage which realized a single to differentiel conversion. The PA is designed and fabricated in a 0.25μm GaN integrated technology from UMS foundry. Both simulations and measurement results are presented. This GaN PA provides 38 dBm of maximum saturated power and 18% to 31% peak PAE in the 4GHz to 11GHz frequency range.

A compact wideband high power amplifier in GaN technology with 47% peak PAE

This article presents a 4-6GHz power amplifier in a 0.25μm GaN integrated technology from UMS foundry. Two unit power cells are combined to increase output power. A new power combiner based on a stacked balun is presented. It has the advantage of occupying a much smaller area than a conventional one. The measured circuit exhibits a peak output power of 37 dBm together with a peak PAE of 47% at 4GHz.

Full Software Radio transceivers

This paper presents the current status and trends in research on Full Software Radio (FSR). Concerning the receiver path after defining Software Defined Radio (SDR) versus FSR a new version of the Sampled Analog Signal Processor (SASP) is presented and experimental results are discussed. The new version doubles the signal bandwidth while the power consumption is reduced to less than 100 mW. For the transmitter path, a new FSR architecture is presented based on Riemanns algorithm and a charge pump. A GaN demonstrator of the Riemanns Pump is presented, which generates any signal including concurrent emissions in the 0-to-1 GHz band.

Dual-mode power amplifier module with in-band reconfigurable output power for multifunctional radar and radio communication systems

This paper presents a concept of dual-mode power amplifier (PA) module with in-band reconfigurable gain and output power. In the first mode, a wideband PA delivers a medium output power. This operational mode is particularly appropriate for ultra-wideband or multi-standard radio communication. In the second mode, a high power amplifier is turned on in order to deliver a high power signal within a sub-band for enhanced radar operation. This second mode allows both amplifiers to operate simultaneously in order to provide continuous service in sidebands. To demonstrate this concept, a network integrating a wideband medium output power PA and a narrowband high power PA is proposed. Both PA are based on low cost SiGe technology and optimized for maximum output power and Power Added Efficiency (PAE) in their operating frequency range. Simulated and measured results of a Printed Circuit Board (PCB) demonstrator validate the concept. The proposed sub-system would be of a great interest for multifunctional radar and radio communication systems.