Getting to wounded soldiers on the battlefield is a precarious task, and medics have a very high casualty
rate. It is therefore a vital importance to prioritize which soldiers to attend to first. The first step is to detect
life signs - if a soldier is dead or alive, and prioritize recovery of live soldiers. The second step is to obtain
vital signs from live soldiers, and use this to prioritize which are in most urgent need of attention. Our
team at Kai Sensors, University of Hawaii and University of Florida is developing Doppler radar heart
sensing technology that provides the means to detect life signs, respiration and/or heart beat, at a distance,
even for subjects lying motionless, e.g., unconscious subjects, wearing body armor, and hidden from direct
view. Since this technology can deliver heart rate information with high accuracy, it may also enable the
assessment of a subject's physiological and psychological state based on heart rate variability (HRV)
analysis. Thus, the degree of a subject's injury may also be determined. The software and hardware
developments and challenges for life signs detection and monitoring for battlefield triage will be discussed,
including heart signal detection from all four sides of the human body, detection in the presence of body
armor, and the feasibility of HRV parameter extraction.
Technology for the detection of enemies from behind barriers and for securing of ports and perimeters with minimal
threat to warfighters is essential in modern threat scenarios. We are developing a network of small scattered Doppler
radar sensors which lie in wait and report on change or motion within a targeted perimeter. Most sensors are simple radar
receiver "nodes" capable of short range communications and long operation life with minimal power requirements,
while a few are more advanced radar transceiver "beacons" capable of active interrogation and long range
communications. Radar nodes and beacons could be scatter-deployed from a distance, creating a need for post-deployment
localization in order to provide useful reconnaissance. A beacon is designed to have absolute position
knowledge by strategic deployment of GPS, produces an interrogation signal, and analyzes locally received echoes for
signs of motion activity in the targeted area. Scattered nodes in the targeted vicinity form an ad-hoc network which also
receives and compares the beacon signal and its target echoes, and reports sensed activity to the beacon. This paper
introduces such a system and discusses radar node localization based on signal strength using kernel methods and
distributed learning algorithms which take energy constraints into account.
Technology that can be used to unobtrusively detect and monitor the presence of human subjects from a distance and
through barriers can be a powerful tool for meeting new security challenges, including asymmetric battlefield threats
abroad and defense infrastructure needs back home. Our team is developing mobile remote sensing technology for
battle-space awareness and warfighter protection, based on microwave and millimeter-wave Doppler radar motion
sensing devices that detect human presence. This technology will help overcome a shortfall of current see-through-thewall
(STTW) systems, which is, the poor detection of stationary personnel. By detecting the minute Doppler shifts
induced by a subject's cardiopulmonary related chest motion, the technology will allow users to detect personnel that are
completely stationary more effectively. This personnel detection technique can also have an extremely low probability of
intercept since the signals used can be those from everyday communications. The software and hardware developments
and challenges for personnel detection and count at a distance will be discussed, including a 2.4 GHz quadrature radar
single-chip silicon CMOS implementation, a low-power double side-band Ka-band transmission radar, and phase
demodulation and heart rate extraction algorithms. In addition, the application of MIMO techniques for determining the
number of subjects will be discussed.
Crosstalk propagating through the silicon substrate is a serious
limiting factor on the performance of advanced mixed analog-digital CMOS integrated circuits. This problem also appears in RF chips in the form of power leakage from local oscillators or power amplifiers, as well as the noise coupled from the digital baseband circuitry. Several studies have presented measurements on simple test structures to determine the best approach to minimize this leakage. Nevertheless, these studies are usually restricted to a single
technology, and the consequences of applying results to other
technologies are not evaluated. Also, these studies are usually
performed with on-wafer samples, and thus package effects are
not taken into account. However, package parasitics are an
important factor in the substrate crosstalk, since they determine how much of the leakage finds a return path to external ground. In this paper, we discuss different technological approaches to increase isolation between coupled circuits. Measurements of the isolation on some test structures fabricated in a CMOS RF technology are presented. The package parasitics effect is evaluated by comparing on-wafer vs packaged samples. Measurement results are complemented with simulations of a broader range of situations.
Proc. SPIE. 4592, Device and Process Technologies for MEMS and Microelectronics II
KEYWORDS: Signal to noise ratio, Switches, Silicon, Interference (communication), Receivers, Transistors, Signal detection, Intermodulation, Standards development, Global system for mobile communications
Third generation (3G) cellular wireless systems are envisioned to offer low cost, high-capacity mobile communications with data rates of up to 2 Mbit/s, with global roaming and advanced data services. Besides adding mobility to the internet, 3G systems will provide location-based services, as well as personalized information and entertainment. Low cost, high dynamic-range radios, both for base stations (BS) and for mobile stations (MS) are required to enable worldwide deployment of such networks. A receiver's reference sensitivity, intermodulation characteristics, and blocking characteristics, set by a wireless standard, define performance requirements of individual components of a receiver front end. Since base station handles multiple signals from various distances simultaneously, its radio specifications are significantly more demanding than those for mobile devices. While high level of integration has already been achieved for second generation hand-sets using low-cost silicon technologies, the cost and size reduction of base stations still remains a challenge and necessity. While silicon RFIC technology is steadily improving, it is still difficult to achieve noise figure (NF), linearity, and phase noise requirements with presently available devices. This paper will discuss base station specification for 2G (GSM) and 3G (UMTS) systems, as well as the feasibility of implementing base station radios in low-cost silicon processes.
A technique has been developed for making 5-parameter measurements of whisker contacted quantum-well diodes with an HP 8510B automatic network analyzer. Special mounts with K connectors were designed to enable measurements up to 20 GHz. Several different quantum-well diodes were succesfully measured. The voltage dependent conductance and capacitance were calculated from the reflection coefficient of each device. These are the first reported 5-parameter measurements in the negative differential resistance (NDR) region of quantum-well devices.