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This paper proposes a new approach for wide angle monitoring of vital signs in smart home applications. The person is tracked using an indoor radar. Upon detecting the person to be static, the radar automatically focuses its beam on that location, and subsequently breathing and heart rates are extracted from the reflected signals using continuous wavelet transform ( C W T ) analysis. In this way, leveraging the radar's on-chip processor enables real-time monitoring of vital signs across varying angles. In our experiment, we employ a commercial multi-input multi-output (MIMO) millimeter-wave FMCW radar to monitor vital signs within a range of 1.15 to 2.3 m and an angular span of − 44.8 to + 44.8 deg. In the Bland–Altman plot, the measured results indicate the average difference of − 1.5 and 0.06 beats per minute (BPM) relative to the reference for heart rate and breathing rate, respectively. [ABSTRACT FROM AUTHOR]

This paper describes and discusses the implementation of a project-based graduate design course in telecommunications engineering. This course, which requires a combination of technical and soft skills for its completion, enables guided independent learning (GIL) and application of technical knowledge acquired from classroom learning. Its main implementation challenge is the need for instructors to define graduate-level GIL activities that are unique for the project objectives and scope. This process is required at both the system and subsystem levels. These activities must also satisfy the program learning outcomes and course outcomes (PLOs and COs). The course initiation, implementation, and management are first described from the instructor's perspective. Technical specifications and outcomes from a recently implemented project titled "A Human-Inspired Telecommunication System" is taken as a case study. Besides explaining the methodology used to evaluate both the course and the students, an empirical assessment of PLOs and COs against the associated educational activities is also presented. Results of a student exit survey, in which each instrument was mapped to specific COs, indicated that the intended course objectives had been accomplished and that there was a good level of student satisfaction.

We developed an efficient method to extract a large-signal lookup table model for InP high electron-mobility transistors that takes impact ionization into account. By measuring the device on a logarithmic frequency scale, we obtain high resolution at lower frequencies to accurately characterize impact ionization, and a sufficient number of data points at millimeter-wave frequencies to extract the nonquasi-static parameters. Model validation through linear and nonlinear device measurements and its application to monolithic-microwave integrated-circuit design are presented. Index Terms--Impact ionization, InP high electron-mobility transistors (HEMTs), large-signal model.

An improved three-stage de-embedding technique to subtract the influence of pad parasitics in silicon on-wafer RF test-structures is presented. This method is more accurate at high frequencies than the current three-step de-embedding method.

Three different electrical stress tests on InP-based high-electron mobility transistors (HEMTs) and their implications concerning reliability are discussed. Hot electron stress, RF overdrive stress and transmission line pulse measurements are investigated to fill a gap in this research area. Until now, reliability assessment of HEMTs has been mainly conducted using high-temperature accelerated stress experiments, while the field of purely electrical stressing has been relatively ignored.

The paper proposes an Indoor Localization System (ILS) which uses only one fixed Base Station (BS) with simple non-reconfigurable antennas. The proposed algorithm measures Received Signal Strength (RSS) and maps it to the location in the room by estimating signal strength of a direct line of sight (LOS) signal and signal of the first order reflection from the wall. The algorithm is evaluated through both simulations and empirical measurements in a furnished open space office, sampling 21 different locations in the room. It is demonstrated the system can identify user’s real-time location with a maximum estimation error below 0.7 m for 80% confidence Cumulative Distribution Function (CDF) user level, demonstrating the ability to accurately estimate the receiver’s location within the room. The system is intended as a cost-efficient indoor localization technique, offering simplicity and easy integration with existing wireless communication systems. Unlike comparable single base station localization techniques, the proposed system does not require beam scanning, offering stable communication capacity while performing the localization process. [ABSTRACT FROM AUTHOR]

A direct K u-band linear subharmonically pumped binary phase-shift keying (BPSK) and in-phase/quadrature (I/Q) vector modulator have been developed using multilayer thin-film multichip module (MCM-D) technology. All passives are integrated in the low cost MCM-D substrate. To the authors knowledge, this is the first modulator based on thin-film integrated passive components. The subharmonic mixing is performed using a beam-lead antiparallel diode pair mounted onto the MCM using thermocompression. A custom diode model has been developed and verified using nonlinear network analyzer measurements: an excellent agreement between the measured and simulated powers and phases for more than nine harmonics is demonstrated. Additionally, it is shown that an optimal reactive termination for the third harmonic of the local oscillator (LO) exists such that a very flat BPSK mixer conversion is obtained. This is validated by measurements that indicate a [+ or -] 0.25-dB variation on the conversion loss for an LO frequency varying from 6.8 to 7.6 GHz. The I/Q vector modulator consists of a Wilkinson power divider, a coplanar-waveguide Lange coupler, and two BPSK modulators. It has a measured image rejection better than -27 dB over the RF range of 13.4-15.2-GHz band (corresponding to a vector phase and amplitude error lower than 2 [degrees] and 1%). The image rejection is even better than -32 dB over the very small aperture terminal band (RF: 14-14.5 GHz). Index Terms--BPSK modulator, integrated passives, MCM-D, QPSK modulator.

An integrated multibias extraction technique for MESFET and high electron-mobility transistor (HEMT) models is presented in this paper. The technique uses s-parameters measured at various bias points in the active region to construct one optimization problem, of which the vector of unknowns contains a set of bias-dependent elements for each bias point and one set of bias-independent elements. This problem is solved by an extremely robust decomposition-based optimizer, which splits the problem into n subproblems, n being the number of unknowns. The optimizer consistently converges to the same solution from a wide range of randomly chosen starting values. No assumptions are made concerning the layout of the device or the bias dependencies of the intrinsic model elements. It is shown that there is a convergence in the values of the model elements and a decrease in the extraction uncertainty as the number of bias points in the extraction is increased. Robustness tests using 100 extractions, each using a different set of random starting values, are performed on measured s-parameters of a MESFET and pseudomorphic HEMT device. Results indicate that the extracted parameters typically vary by less than 1%. Extractions with up to 48 bias points were performed successfully, leading to the simultaneous determination of 342 model elements. Index Terms--Decomposition, HEMT, linear, MESFET, modeling, multibias, optimization, parameter extraction.