International Journal

This paper presents a radio frequency (RF) continuous-time band-pass delta sigma modulator (CT BP DSM) receiver realized in a 180 nm SiGe BiCMOS technology. It also provides an introduction to active antenna systems (AAS) for cellular infrastructure base stations, which is the target application for this RF integrated circuit (IC). The internal quantizer and feedback digital to analog converter (D

Emerging intrinsically tunable film bulk acoustic wave(BAW) resonators allow the development of new generation reconfigurable and agile microwave circuits. In this paper, we demonstrate the enhancement of tunable performance of the high Q-factor BaSrTiO BAW ? solidly mounted resonators (BAW?SMR) by varying Ba concentration. The BaSrTiO BAW?SMR reveal tunability of series resonance frequency up to

In this paper, we present the results of using a frequency-stepped continuous-wave radar system to estimate the position of overlapping and electrically good conductive plates. We especially focus on polarimetric scattering effects caused by the step of a lap joint, which is a common welding-geometry. To model the step's contribution to the overall scattered signal, we use a two-dimensional combin

This paper presents a novel, compact, single-sideband (SSB) subharmonically-pumped (SHP) direct upconverter developed in a uniplanar 0.18 ?m GaAs technology. A total of 100 MHz in-phase and quadrature signals directly modulate the second harmonic of a 30 GHz carrier signal, producing a 60.1 GHz output. Two pairs of antiparallel diodes reduce feed-through of the 30 GHz local oscillator (LO) signal

In this work, the possibility of achieving GaN-on-Si devices for millimeter wave applications operating at high bias is demonstrated. It is shown that highly scaled AlN/GaN-on-Si double heterostructure enables us to significantly improve electron confinement under high electric field as compared to single heterostructure while delivering high carrier density (>2 × 10 cm). Subsequently, trapping ef

Two types of optoelectronic oscillators delivering high spectral purity microwave signals are presented in this paper. These oscillators use the Pound?Drever?Hall laser stabilization technique to lock the laser carrier onto two different types of passive optical resonators featuring high-quality factors: a fiber ring resonator (FRR) and a whispering gallery mode monocrystalline disk-shaped micro-r

In this article, a novel motion model-based particle filter implementation is proposed to classify human motion and to estimate key state variables, such as motion type, i.e. running or walking, and the subject's height. Micro-Doppler spectrum is used as the observable information. The system and measurement models of human movements are built using three parameters (relative torso velocity, heigh

This paper presents for the first time a novel concept of a microelectromechanical systems (MEMS) waveguide switch based on a reconfigurable surface, whose working principle is to block the wave propagation by short-circuiting the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. The reconfigurable surface is only 30 µm thick and consists of up to 1260 micromachined cantile

Phase unwrapping (PU) is one of the key processing steps in reconstructing the digital elevation model (DEM) of a scene from interferometric synthetic aperture radar (InSAR) data. The PU problem entails the estimation of an absolute phase from observation of its noisy principal (wrapped) values. Recently, PU approaches based on Kalman filtering have proved their efficacy in tackling the PU problem

In this paper a monostatic frequency-modulated continuous-wave (FMCW) radar system around a center frequency of 24 GHz with a wide tuning range of 8 GHz (?33%) is presented. It is based on a fully integrated single-channel SiGe transceiver chip. The chip architecture consists of a fundamental VCO, a receive mixer, a divider chain, and coupling/matching networks. All circuits, except for the divide