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In this study, a constant-bandwidth variable-gain amplifier (VGA) is presented for long-term evolution (LTE) receivers. The presented VGA’s description is given with a newly proposed exponential-current generator, and also the common-mode feedback and the DC-offset cancellation (DCOC) circuits. The proposed exponential current generator is based on the Taylor series approximation in such a way that it can be expanded to meet the required gain control range. The simulations are performed using the TSMC 180 nm process technology with Cadence Analog Virtuoso. The VGA has a 45 dB gain control range, 180 MHz bandwidth, 15.7 dB m the third-order input-intercept point for minimum gain and below 20 dB noise figure for maximum gain which makes it convenient for LTE receivers. The simulations also show that the bandwidth of the VGA is fairly constant over the control range. Monte Carlo simulations reveal that by using a DCOC circuit, the VGA provides 30 dB output offset rejection. The overall power consumption of the circuit is 9.1 mW under a 1.8 V power supply.

A compact active inductor circuit is proposed. The circuit is based on the gyrator-C approach with both transconductance stages realized by MOS transistors in common-source configuration. The circuit has minimal number of transistors, is suitable for low voltage operation, offers a wide inductive band, high quality factor and low power dissipation. Simulation results are provided for a 0.13 μm CMOS process with 1.2 V supply voltage.

The use of polymer-based composite materials in the aircraft and automotive industries has been rapidly increasing. In this paper the impact efficiency of some polymer-based composites is experimentally studied. This involved the manufacture of a quantity of thermosetting resin composite specimens using the hand lay-up process. Subsequently ballistic testing was performed using a selection of commonly available firearms with the resulting characteristics experimentally obtained using mechanical and C-scan methods. The results were compared relatively and with previous studies. Eventually the promising advantages for using such materials on an armoured car are emphasized.

One of the materials commonly used in the aerospace and automotive industries is polymer-based composites. It also has potential for even greater usage. In this paper the ballistic impact performance of some polymer-based composites is experimentally considered. This entailed the manufacture of a number of thermosetting resin composite specimens using the hand lay-up process. Thereafter ballistic testing was carried out using a variety of commonly available firearms with the resulting properties experimentally obtained using mechanical and ultrasonic methods. The results were compared relatively with previous studies. Finally the potential benefits for using such materials on an armoured saloon car is highlighted.

Summary This paper reports five new single-input multiple-output current-mode multifunction filter circuits which can simultaneously realise three basic filter functions all at high impedance outputs. The circuits employ only the same type of active elements, grounded passive components, andno element matching conditions are imposed. The filters permit orthogonal adjustment of the quality factor Q and angular resonant frequency ω 0 . The active/passive sensitivities are shown to be low.

In active filters, the performance of the active element plays an important role in the overall performance of the filter, besides the filter configuration itself. In this paper, we will investigate the effects of current conveyor non-idealities on a certain class of filters which consists of four current conveyors and seven nodes, and derive analytical expressions for the filter parameter deviations in terms of non-ideality terms. The results obtained apply to all filters under this class which are considerable in number. This will enable us to determine the requirements for the current conveyor non-ideality terms in order to obtain a specified filter performance. A comparable demonstration of the filter transfer functions for two example current conveyor circuits will be given. Simulations including three types of filters, namely, the bandpass, lowpass and highpass filters, confirm the analytical expressions obtained.

Stacked conical ring dielectric resonator antennas (DRA) excited by an axi-symmetric coaxial monopole are investigated numerically and experimentally for improved bandwidth. The bandwidth improvement is due to an extra resonance which occurs near the frequency where the monopole height is about a full wavelength. We consider two cases of the hybrid antenna: one case in which the tips of both cones face up and a second case in which the top cone is inverted to form a 'sand-glass' shaped DRA. Measured data were obtained to validate the results of simulations. The proposed hybrid antennas can easily offer a fractional impedance bandwidth up to 138% along with monopole type radiation pattern. The antennas have a relatively low peak gain around the extra resonance. © 2012 IEEE.

An active radio frequency (RF) filter based on floating active inductor circuits is presented in this work. For demonstration purposes, a third-order Chebyshev lowpass filter with an LC ladder structure has been designed for GSM applications. The filter has a cutoff frequency of 900 MHz and 0.4 dB ripple, and is tunable between 890 MHz and 960 MHz, consumes 10.5 mW power, and occupies an area of 96 mumtimes135 mum when laid out using the UMC 0.13 mum CMOS process which provides an area reduction of 80% compared to its passive filter counterpart.

This paper presents the design of a low-noise amplifier (LNA) with high gain and low noise figure (NF), targeting the X-band, in 0.25 mum SiGe BiCMOS process provided by IHP. Simulation results show that at 10 GHz, the proposed LNA has a noise figure of 2.295 dB, with both input and output impedances matched to 50 Omega, an input return loss of -30.22 dB, an output return loss of -17.02 dB, and a voltage gain of 20.74 dB while dissipating 7.5 mW power from a 2.5 V power supply. The circuit occupies a chip area of 590 times 765 mum2.

In this work, a novel aided-acquisition technique based on proportional-integral-derivative (PID) control of a phase-locked loop (PLL) is presented. This is achieved by inserting a control block into the PLL during acquisition where originally the output frequency/phase is controlled by a PI controller. This significantly reduces the settling time of the PLL which is important for certain applications such as WLANs where fast frequency-hopped spread-spectrum methods are used. Simulations show that the proposed structure reduces the settling time by 75%.

In this work, two voltage-mode filters, a first-order and a second-order structurely allpass filter, realized with active components only, are presented. The circuits employ only operational transconductance amplifiers (OTA) and internally compensated operational amplifiers (OA). The second-order filter parameters are independently adjustable. Simulation results are included to verify theory.

This paper describes a simple and accurate current conveyor macromodel which is suitable for simulation of active filter applications. The results obtained show that the proposed macromodel approximately represents the current conveyor with the same accuracy of the semiconductor, SPICE device models, but with a considerably reduced computer time.

A new voltage-mode universal active filter employing only two CCII+s and a minimum number of capacitors is proposed. The active and passive sensitivities are lower than unity and not dependent on the quality factor Q. The use of only CCII+s simplifies the configuration. Dynamic range of the filter is studied and a simple formula is derived for input signal amplitude not causing clipping problems for the proposed bandpass filter. Simulated results verifying the theoretical approaches are also included.

A new configuration for the realization of very high-Q filters with electronically controllable filter parameters is presented. For this purpose, first, a modification for the translinear CMOS CCCII and then, a new high-performance first-order allpass filter section are proposed. The main parameters of the resulting high-Q bandpass filter, ie. the center frequency and pole-Q can be independently adjusted via DC bias currents. It is also shown that the filter sensitivities with respect to capacitors mid intrinsic resistances are low. SPICE simulation results verify the theoretical analyses.

This paper presents two second-order lowpass filters realized with operational amplifiers (OA) and operational transconductance amplifiers (OTA) only. The circuits do not require additional passive components, which makes them suitable for integrated circuit (IC) implementation and reduces chip area. The filter parameters can be adjusted independently. Simulation results are included to verify theory.

This paper presents a new current-mode universal filter using dual output current conveyors. The proposed filter can simultaneously realize three basic filter functions all at high impedance outputs. The circuit employs only the same type active elements and grounded passive components. The resonant angular frequency and the quality factor can be orthogonally controllable. The passive sensitivities are shown to be low. PSPICE simulation results are also included.

This paper presents a new single-input multi-output type current-mode multifunction filter. The proposed filter can simultaneously realize three basic filter functions, all at high impedance outputs. The circuit employs only the same type of active elements and grounded passive components, permitting orthogonal adjustment of quality factor Q and /spl omega//sub p/ where no element matching conditions are imposed. The passive sensitivities are shown to be low.

This paper presents a high performance current differencing buffered amplifier (CDBA), a recently reported active component, especially suitable for analog signal processing applications. It employs two second generation current conveyors (CCII) and a voltage buffer. The circuit contains only MOS transistors and is designed to be implemented in CMOS technology. Simulated device characteristics show that the proposed circuit exhibits a very good performance and offers new opportunities for analog circuit designers. A first-order all-pass filter circuit was chosen as an application example in order to demonstrate the performance of the CDBA. It will be seen that simulation results verify the theory.