A CW Nd:YAG master oscillator power amplifier with fibre based SBS phase conjugate mirror is reported. A four-pass amplifier configuration is employed to compensate pump induced thermal lens and birefringence in the amplifier rod in conjunction with a fibre phase conjugator to achieve diffraction limited output beam quality. Maximal attainable gain of ;1.9 for the system is obtained. Applicatio...

The ubiquitous network society is evolving at an accelerated pace using various mobile communication tools, especially mobile phones. The driving force behind such a rapid development of the network is the rise in requirements of various bandwidth sensitive user applications. This leads to a demand for large capacity mobile communications, with availability anytime, anywhere and with anything. ...

Orthogonal frequency division multiplexing (OFDM) is a strong candidate for future wireless communication because it is marked by its higher frequency multiplicity and greater immunity to multipath fading. However, the main drawback of OFDM is high peak-to-average power ratio (PAPR), which leads to power inefficiency and requires expensive high power amplifier (HPA) with very good linearity. In...

Radio Frequency (RF) power amplifiers (PAs) are one of the most important elements in radio telecommunication facilities, which are used to amplify the power of input signals. At the same time, they gradually become the bottleneck for modern telecommunication systems due to the confliction between the linearity and the efficiency, resulting in their relatively high level energy consumption. Vol...

This paper presents the design of a reconfigurable power amplifier for Mobile WIMAX applications in the user terminal. The amplifier, which operates from 3.4GHz to 3.5GHz, is based on the Doherty technique. This power efficiency enhancement technique is suitable for modern wireless communications systems, as Mobile WIMAX, that present with high peak-to-average power ratio (PAPR) to target high ...

We demonstrate a new type of four-pass dye laser amplifier that can reduce the possibility of parasitic oscillation between optical components used in the amplifier. Pumping the amplifier with a 5.6-mJ Q-switched doubled Nd:YAG laser output, we obtain high-peak-power pulsed output of an incident cw narrow-bandwidth dye laser beam with a power gain greater than 2 x 10(6) . Subsequent amplificati...

Wide frequency bandwidth has been internationally allocated for unlicensed operation around the oxygen absorption frequency at 60 GHz. A power amplifier and a low noise amplifier are presented as building blocks for a T/R-unit at this frequency. The fabrication technology was a commercially available 0.15 μm gallium arsenide (GaAs) process featuring pseudomorphic high electron mobility transist...

A low-power, high-gain CMOS low noise amplifier (LNA) for use as the first stage of a subsampling receiver is proposed. The performance of +96-dB voltage gain and less than 1-dB Noise Figure (NF) with very low power consumption is reported for the first time and makes it suitable for subsampling mixer with Track and Hold (T/H) circuit. The LNA contains both tuned and inductorless amplifier stag...

This paper describes the design of a fully differential CMOS amplifier for clipping control circuit. The amplifier with specification of low settling time less than 5ns, high dynamic range above 90dB and low power supply of 3 volt is designed and realized in a 0.35 μm CMOS process with 3 volt power supply. Simulation confirm the presented design.

a high accurate and low-voltage analog cmos current divider which operates with a single power supply voltage is designed in 0.18µm cmos standard technology. the proposed divider uses a differential amplifier and transistor in triode region in order to perform the division. the proposed divider is modeled with neural network while tlbo algorithm is used to optimize it. the proposed optimization...