http://www.acsu.buffalo.edu/~jmjornet/papers/2014/j1.pdf

Full length article: Terahertz band: Next frontier for wireless communications

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

/pdf/response-to-fcc-98-208-notice-of-inquiry-in-the-matter-of-3attixctl7.pdf

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

The recent approval granted by the Federal Communications Commission (FCC) for the use of ultra-wideband signals for vehicular radar applications has provided a gateway for the introduction of these sensors in the commercial arena as early as 2004. However, the rules governing the allowable spectral occupancy create significant constraints on the sensors' operation. This is further complicated by the variety of applications that these sensors are being required to fulfill. A review of the motivation for the development of these sensors is followed by a discussion of the consequent implications for waveform design and limitations on system architecture. Other practical considerations such as available semiconductor technology, packaging, and assembly techniques are reviewed, and results are presented for conventional surface-mount plastic packages illustrating their usefulness in the greater than 20-GHz frequency range. Suitable antenna technology for wide-band transmission is presented that is compliant with the specific restrictions stipulated in the FCC ruling. Finally, all of these considerations are combined with the presentation of a compatible integrated-circuit-based transceiver architecture. Measured results are presented for several critical circuit components including a +12-dBm driver amplifier for the transmitter, an RF pulse generator that can produce sub-1-ns pulses at a carrier frequency of 24 GHz, and a single-chip homodyne in-phase/quadrature down-conversion receiver that has a cascaded noise figure of less than 7 dB. All circuit components are fabricated in SiGe.

Ultra-wideband radar sensors for short-range vehicular applications

This paper presents a hybrid radar system that incorporates a linear frequency-modulated continuous-wave (FMCW) mode and an interferometry mode for indoor human localization and life activity monitoring applications. The unique operating principle and signal processing method allow the radar to work at two different modes for different purposes. The FMCW mode is responsible for range detection while the interferometry mode is responsible for life activities (respiration, heart beat, body motion, and gesture) monitoring. Such cooperation is built on each mode's own strength. Beam scanning is employed to determine azimuth information, which enables the system to plot 360° 2-D maps on which the room layout and objects' location can be clearly identified. Additionally, the transmitted chirp signal is coherent in phase, which is very sensitive to physiological motion and allows the proposed technique to distinguish human from nearby stationary clutters even when the human subjects are sitting still. Hence, the proposed radar is able to continuously track the location of individuals and monitor their life activities regardless of the complex indoor environment. A series of experiments have been carried out to demonstrate the proposed versatile life activity monitoring system.

A Hybrid FMCW-Interferometry Radar for Indoor Precise Positioning and Versatile Life Activity Monitoring

In this paper an impulse-radio ultra-wideband (IR-UWB) hardware demonstrator is presented, which can be used as a radar sensor for highly precise object tracking and breath-rate sensing. The hardware consists of an impulse generator integrated circuit (IC) in the transmitter and a correlator IC with an integrating baseband circuit as correlation receiver. The radiated impulse is close to a fifth Gaussian derivative impulse with $\sigma=51\ {\hbox {ps}}$ , efficiently using the Federal Communications Commission indoor mask. A detailed evaluation of the hardware is given. For the tracking, an impulse train is radiated by the transmitter, and the reflections of objects in front of the sensor are collected by the receiver. With the reflected signals, a continuous hardware correlation is computed by a sweeping impulse correlation. The correlation is applied to avoid sampling of the RF impulse with picosecond precision. To localize objects precisely in front of the sensor, three impulse tracking methods are compared: Tracking of the maximum impulse peak, tracking of the impulse slope, and a slope-to-slope tracking of the object's reflection and the signal of the static direct coupling between transmit and receive antenna; the slope-to-slope tracking showing the best performance. The precision of the sensor is shown by a measurement with a metal plate of 1-mm sinusoidal deviation, which is clearly resolved. Further measurements verify the use of the demonstrated principle as a breathing sensor. The breathing signals of male humans and a seven-week-old infant are presented, qualifying the IR-UWB radar principle as a useful tool for breath-rate determination.

/pdf/ir-uwb-radar-demonstrator-for-ultra-fine-movement-detection-3mwfwxyrfi.pdf

IR-UWB Radar Demonstrator for Ultra-Fine Movement Detection and Vital-Sign Monitoring

A short range 3.1-10.6 GHz single band ultra-wideband (UWB) pulse radar system is presented. The transmitter consists of a pulse generator that is connected to a broadband monopole antenna. The generated pulse shape is similar to the fifth derivative of the Gaussian bell shape and makes efficient use of the allocated FCC UWB frequency mask. The receiver is realized with a single-ended low noise amplifier and active single-ended to differential converters that drive the input ports of an analog correlator which uses pulse sequences as template signals. Measurements show a resolution capability of the radar system in the millimeter range. All active circuits have been realized in a low cost 0.8 mum SiGe HBT technology.

/pdf/fcc-compliant-3-1-10-6-ghz-uwb-pulse-radar-system-using-2fu772h8fo.pdf

FCC compliant 3.1-10.6 GHz UWB Pulse Radar System using Correlation Detection

The authors have demonstrated a fully integrated receiver frontend addressing the ISM-Band at 24 GHz utilizing a standard SiGe HBT MMIC process with a relaxed emitter scaling of 1.2 /spl mu/m, for the first time. Extremely compact circuit design and layout techniques are applied to a mature Si/SiGe technology, resulting in a low-cost integrated circuit enabling consumer-oriented systems at Ka band. The integrated components are a preamplifier, a mixer with an IF buffer and a local oscillator. The conversion gain is determined to be 16.3 dB for an intermediate frequency of 100 MHz.

A single-chip 24 GHz receiver front-end using a commercially available SiGe HBT foundry process

This paper presents the design and characterization of an ultra wideband FMCW radar sensor. The radar frontend consists of transmitter and receiver chips in SiGe BiCMOS technology with on-chip antennas. Both chips share the same reference chirp signal, multiplied 8 times to the desired operation band. The radar frontend demonstrates a bandwidth of 56.8 GHz from 104.4 GHz to 161.2 GHz, which corresponds to a theoretical range resolution of 2.6mm. The on-chip antenna occupies only 1.2 × 0.9mm
 2
 without any post-micromachining and exhibits a measured gain above 4 dBi for more than 28 GHz of bandwidth. The sensor covers a bandwidth from 105 to 160 GHz with about 10 dB Tx-to-Rx gain fluctuation and less than 39 dBc harmonic power. The radar sensor was tested with FMCW chirps for different scenarios, showing a range resolution of approximately 5 mm.

56 GHz bandwidth FMCW radar sensor with on-chip antennas in SiGe BiCMOS

This paper presents a low-cost, low-loss solution for IC-to-board interconnects using bondwires. With an L-C-L structure to compensate the influence of bondwires, low insertion loss and high return loss can be achieved. Optimized at 60 GHz, an insertion loss of 0.1 dB is achieved for the differential connection and 0.3 dB is achieved for the single-ended connection, with additional radial stubs to compensate the influence of the ground bondwire. The 1-dB bandwidth of the interconnect is larger than 10 GHz (16% relative bandwidth at 60 GHz). The low-cost and low-loss characteristic makes the interconnect well suited for millimeter-wave packaging and module design.

Andreas Trasser

Papers

IR-UWB Radar Demonstrator for Ultra-Fine Movement Detection and Vital-Sign Monitoring

FCC compliant 3.1-10.6 GHz UWB Pulse Radar System using Correlation Detection

A single-chip 24 GHz receiver front-end using a commercially available SiGe HBT foundry process

56 GHz bandwidth FMCW radar sensor with on-chip antennas in SiGe BiCMOS

Low-loss, low-cost, IC-to-board bondwire interconnects for millimeter-wave applications