Gyrotron frequency amplifier has been used for the production of highly charged ion beams with high performance ECR ion sources (ECRIS) for almost 20 years. The widely used technology of microwave power coupling to the high temperature ECR plasma is still a borrowed design from the fusion machines. ECR ion source technologies and physics are advancing over the years, but the interpretation of h...

a novel low noise trans-impedance amplifier is proposed using low cost 0.18 µm cmos technology. a resistive-capacitive feedback is used to extend the bandwidth of the amplifier. as the structure is inductor less, it is suitable for low cost integrated optical interconnects. in this paper improved particle swarm optimization have applied to determine optimal trans-resistance and noise of propose...

a digital look-up table adaptive predistortion technique using a six-port receiver for power amplifier linearization is presented. the system is designed in ka-band for a dvb-s2 satellite link. we use a six-port receiver at the linearizationloop in place of classic heterodyne receivers. the six-port receiver is implemented by the use of passive microwavecircuits and detector diodes. this approa...

Conventional altimeters include nadir looking colocated 18-37 GHz microwave radiometer to measure wet tropospheric path delay. These have reduced accuracy in coastal zone (within ~50 km from land) and do not provide wet path delay over land. The addition of high frequency channels to Jason-class radiometer will improve retrievals in coastal regions and enable retrievals over land. High-frequenc...

This paper describes a new approach for designing analog cubic predistorters in view of minimizing non linear distortion introduced by the high power amplifier (I-IPA) in microwave radio links. The approach is based on a global mean squared error minimization between the input to the predistorter and the output of the power amplifier, rather than on the elimination of the cubic term. In this ma...

A new approach for the electro-thermal modeling of LDMOSFETs for power-amplifier design that bypasses pulsed-IVs and pulsed-RF measurements is presented in this paper. The existence of low-frequency dispersion in LDMOSFETs is demonstrated by comparing pulsed IVs with iso-thermal IVs. The modeling technique uses iso-thermal IV and microwave measurements to obtain the temperature dependence of sm...

Superconducting circuits and devices have unique properties that make them interesting from both theoretical and practical perspective. In a superconductor cooled below its critical temperature, electrons bound in Cooper pairs have the ability to carry current without dissipation. A structure where the Cooper pairs are coherently tunneling across a weak link is called a Josephson junction (JJ)....

While often overlooked, one of the prerequisites for high-speed amplitude modulation atomic force microscopy is a high-bandwidth amplitude estimation technique. Conventional techniques, such as RMS to DC conversion and the lock-in amplifier, have proven useful, but offer limited measurement bandwidth and are not suitable for high-speed imaging. Several groups have developed techniques, but many...

Efficiency and linearity of the microwave power amplifier are critical elements for mobile communication systems. This paper discusses improvements in system efficiency that are obtainable when a dc–dc converter is used to convert available battery voltage to an optimal supply voltage for the output RF amplifier. A boost dc–dc converter with an operating frequency of 10 MHz is demonstrated usin...

The design of a 50 0 impedance matched two-tofour level converter GaAs IC for two-electrode semiconductor optical amplifier (SOA) modulators is presented. The designed IC exhibits eye diagrams with eye openings of better than 0.30 V and a spacing between adjacent output signal levels of 0.33 V for output symbol rates of up to 2 Gsym.boVs corresponding to input bit rates of up to 4 Gb/s. A novel...