Airborne capacitive micromachined ultrasonic transducers (CMUTs) have predominantly large input reactance with small series radiation resistance. To maximize the acoustic power at resonance we employ low cost LC matching networks between output impedance driving source and CMUT transducer. Conventional networks, including pi T-network topologies are employed to provide a high-Q match. An import...

UMTS transmitters in handsets, based on WCDMA, have to fulfill contradicting requirements. On the one hand, they should operate in a highly power efficient way because battery lifetime is a major consideration for handsets. For this purpose, the application of switchedmode RF power amplifiers seems to be advantageous. On the other hand, the spectral efficiency of the transmitted signal has to b...

A sliding k-transmitter in an orthogonal polygon P is a mobile guard that travels back and forth along an orthogonal line segment s inside P . It can see a point p ∈ P if the perpendicular from p onto s intersects the boundary of P at most k times. We show that guarding an orthogonal polygon P with the minimum number of k-transmitters is NP-hard, for any fixed k > 0, even if P is simple and mon...

Nowadays the main driving parameters for the radio transmitter research are: energy efficiency, frequency re-configurability and integration. Pulsed transmitter architectures have attracted large interest in the recent years due to their potential to meet these demands. In pulsed transmitters, a highly efficient switch mode power amplifier (SMPA) is used in conjunction with a pulse modulator to...