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This paper presents a new method for ring amplifier biasing to improve their stability while maintaining high slew rate. A multi-path ring amplifier is proposed for switched capacitor applications that allows accurate charge transfer at high speeds. Dynamic biasing improves large signal slewing without affecting residue amplifier settling performance. Stable operation is possible because the auxiliary...
In this paper, we investigate the effect of frequency uncertainty in the signals generated or measured by a microwave instrument on the resulting synthetic aperture radar (SAR) images for nondestructive testing (NDT) applications. Wideband SAR imaging systems measure reflections from a target by irradiating it with locally generated signals that can potentially have some level of frequency uncertainty...
In this work, a capacitance-to-voltage converter based on a fully-differential transimpedance amplifier (TIA) with programmable gain and bandwidth for MEMS accelerometers is presented. It is aimed for a differential surface-micromachined comb-finger capacitive accelerometer, but can be used in many other capacitive sensor applications. The TIA has been designed in a 180-nm CMOS technology and it achieves...
A millimeter-wave fully differential power amplifier with broadband performance was implemented in 90-nm CMOS technology. The proposed circuit employed a three-dimensional layout for a cascode power cell to reduce the sensitive parasitic effect. The proposed power amplifier provides a 3-dB bandwidth region ranging from 44.7 to 58.8 GHz, with a maximum small-signal gain of 21.6 dB at 49 GHz. In addition,...
We propose a simple but effective approach for the estimation of power spectra at very low frequencies (down to the tens of mHz range) by exploiting the characteristics of the sound system (sound card) and the computational power of modern personal computers. A simple mixer board has been designed that allows to transfer the low frequency region of the spectrum at a higher frequency in the passband...
We propose a decentralized algorithm to help reduce demand-supply imbalance in a power grid by varying the demand from loads, just like charging and discharging a battery. The algorithm ensures strict bounds on the consumers' quality of service (QoS) by constraining the bandwidth of demand variation. A model-predictive-control formulation is adopted to compute local decisions at the loads. The algorithm...
A fundamental but often overlooked component in the z-axis feedback loop of the atomic force microscope (AFM) operated in dynamic mode is the demodulator. Its purpose is to obtain a preferably fast and low-noise estimate of amplitude and phase of the cantilever deflection signal in the presence of sensor noise and additional distinct frequency components. In this paper, we implement both traditional...
This paper presents measurement results of a recently introduced time of flight (ToF) ranging method for backscattering RFID tags. The measurements are done with off-the-shelf EPC Class1 Gen2 tags, an automated tag positioner, a modified software defined radio (SDR) platform as the RFID reader, and a PC post-processing the ranging results. The ranging error and its variance is measured and discussed...
We propose a model-based compressed sensing (MBCS) of FBG arrays (FBGA), interrogated with wavelength scanning incoherent optical frequency domain reflectometry. This method measures the frequency response of a FBGA with an electrical vector network analyzer combined with a tunable laser. Instead of the usual inverse discrete Fourier transform (IDFT), we apply a direct estimation of the grating reflectivities...
Metamaterial-inspired near-field resonant parasitic (NFRP) electrically small antennas (ESAs) have been designed and experimentally validated to have not only high radiation efficiencies, but also multi-functionality, large bandwidths, high directivities and reconfigurability. These expanded capabilities have been attained by introducing more complex meta-structures, i.e., multiple NFRP elements loaded...
This paper presents a planar, broadband, electrically-small, circularly polarized (CP), near field resonant parasitic (NFRP) antenna fed by a crossed dipole driver. The driven and parasitic elements are printed on two separate thin substrates, which are stacked together with no air-gap to achieve the compact planar configuration. The technique of introducing meander lines and arrowhead-shaped endings...
With the proliferation of wireless electronic devices such as RFID, In-flight Entertainment (IFE) and Personal Electronic Devices (PED) it is important to understand how these systems interact with one another and flight critical systems onboard aircraft. Overall system performance is also of interest due to the varying system performance based on subcomponent installation locations. This paper describes...
This paper presents wideband channel measurements in an office environment in the 62 GHz and 83 GHz frequency bands. Measurements were performed with a VNA and the mechanical steering of directive antennas at both the transmitter and receiver side, allowing a double-directional angular characterization. A comparison of propagation characteristics such as the path loss, multipaths clusters' dispersion...
A novel compact size equilateral triangular ring-slot antenna is proposed for microsatellite. The presented antenna utilizes truncation, perturbation, and slits to generate wideband circular polarization (CP) operation from its inherited linear polarization. The fabricated antenna has wide CP performance of 1106 MHz or 52.27% of fractional bandwidth at 2116 MHz center frequency. The measured results...
There is considerable interest in determining differences between radio channel characteristics in the currently allocated mobile radio frequency bands and bands that might be allocated for this purpose in the future. This paper is therefore devoted to a determination and comparison of channel characteristics caused by multipath (time) dispersion on microcellular mobile radio channels at frequencies...
A new technique is developed to best locate the coaxial feed of a circularly polarized stacked microstrip antenna (CPSMA) with the objective of improving the axial-ratio (AR) bandwidth and CP quality of the antenna. In the proposed technique, we move the single feed on an arc between the diagonal and main axis of the driven patch to optimize CP performance. An antenna based on this technique has been...
A reflectarray antenna composed of double cross loop elements of varying arm length printed on a conductor-backed substrate is introduced. Two different realizations are presented: in the first design, the lengths of both constituent arms of the cell elements are varied whereas the length of only one of the two arms is varied in the second design. Prototype reflectarrays were fabricated and measured...
The development of a very wideband balanced stripline printed dipole array placed above a conducting ground plane, as shown in Fig. 1, is discussed in this paper. A balanced printed dipole has its arms printed on the top and bottom conducting plane of a thin substrate mounted normal to the array ground plane. An integrated matching network forms the centre conductor of the stripline feed. The arms...
This paper describes the design of a low cost 4-bit switched line phase shifter microwave integrated circuit (MIC) on a 10 mil Alumina substrate. Schiffman coupled lines were used to implement each of the 4 bits. These coupled lines provide a dispersive phase response which can be used to produce a relatively constant phase shift over a large bandwidth. Over the 4–8 GHz frequency range, initial measurements...
Properties of a novel broadband printed antenna element, printed counterpart of the conventional TV UHF panel antenna with very large bandwidth, has been studied. A design method and realization is presented in the paper. More than one octave measured bandwidth with VSWR less then 1.8 and directivity between 9.0 and 11.0 dBi has been achieved. Properties of the radiator as an array element have also...
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