RF power amplifier

About: RF power amplifier is a research topic. Over the lifetime, 21191 publications have been published within this topic receiving 294253 citations.

Large suspended inductors on silicon and their use in a 2- mu m CMOS RF amplifier

Abstract: Large spiral inductors encased in oxide over silicon are shown to operate beyond the UHF band when the capacitance and loss resistance are greatly reduced by selective removal of the underlying substrate. Using a 100-nH inductor whose self-resonance lies at 3 GHz, a balanced tuned amplifier with a gain of 14 dB centered at 770 MHz has been implemented in a standard digital 2- mu m CMOS IC process. The core amplifier noise figure is 6 dB, and the power dissipation is 7 mW for a 3-V supply. >

RF Power Amplifiers for Wireless Communications, Second Edition (Artech House Microwave Library (Hardcover))

Abstract: This extensively revised edition of the bestselling Artech House book, RF Power Amplifiers for Wireless Communications, offers you a comprehensive, practical, and up-to-date understanding of how to tackle a power amplifier design with confidence and quickly determine the cause of malfunctioning hardware. Among the numerous updates, the Second Edition includes five new chapters on class AB PAs at GHz frequencies; switching PA modes at GHz frequencies; signals, modulation systems, and PA nonlinearities; power amplifier bias circuit design; and load-pull techniques. Chapters on efficiency enhancement methods and Class F design have been substantially extended, and many more practical examples and design tools are included on the accompanying CD-ROM. Supported with nearly 200 illustrations, the book contains the most complete survey of RF PA efficiency enhancement and linearization techniques in a single volume. It helps you design suitable matching networks which provide correct fundamental harmonic terminations for conventional (AB, B) high efficiency PA modes, understand the Class D, E, and F modes and their feasibility at microwave frequencies, and use envelope simulation techniques to analyze the effects of distortion in overdriven PAs. You learn how to maintain high efficiency operation at low points in an amplitude modulated signal envelope, including detailed coverage of the Doherty, Chireix, and Kahn techniques. Moreover, this authoritative resource helps you understand the possibilities and limitations of linearization methods, and offers guidance in objectively analyzing PA stability and oscillation problems.

Dual-channel RF power delivery system

Abstract: A dual-channel RF power delivery system for applying RF energy to dual electrodes of an RF ablation device with independent control of the power level, frequency, phase, and time duration of the RF energy applied to each electrode to more accurately control the ablation of a target tissue. The power delivery system supplies a first controlled RF signal having a first power level, frequency, phase, and time duration to the electrode of a first flexible stylet and a second controlled RF signal having a second power level frequency, phase, and time duration to the electrode of a second flexible stylet. The difference between the first and second power levels and the temperature of the tissue between the first and second stylers are monitored to control the ablation of the target tissue. The supply of the first RF signal is terminated when the monitored temperature of the first stylet exceeds a first predetermined value and the supply of the second RF signal is terminated when the monitored temperature of the second stylet exceeds a second predetermined value. By adjusting the frequency and/or phase of the first and second RF signals, the relative amounts of bipolar and monopolar ablation can be adjusted for accurate control of the lesion volume. The lesion volume can also be controlled by varying the deployment length of the electrodes.

Temperature controlled rf coagulation

Abstract: Radiofrequency medical devices for ohmic heating of tissue of a patient include a temperature sensor (29) carried by and in thermally conductive relationship with a thermally conductive electrode (28). The sensor (29) is connected for feedback to a control circuit (6) that modulates RF power applied to the electrode according to the signal received from the temperature sensor (29). The control circuit (6) and RF power supply alternate between two operating modes. In the first mode the RF power supply applies RF power to the electrode (28). In the second mode the control circuit (6) senses a signal from the temperature sensor (29) in the absence of RF signal. The control circuit (6) compares the signal from the temperature sensor (29) to a set value and modulates the RF power applied to the electrode (28) in accordance with the set value.

Design and experiments of a high-conversion-efficiency 5.8-GHz rectenna

Abstract: A high-efficiency rectenna element has been designed and tested at 5.8 GHz for applications involving microwave-power transmission. The dipole antenna and filtering circuitry are printed on a thin duroid substrate. A silicon Schottky-barrier mixer diode with a low breakdown voltage is used as the rectifying device. The rectenna element is tested inside a waveguide simulator and achieves an RF-to-DC conversion efficiency of 82% at an input power level of 50 mW and 327 /spl Omega/ load. Closed-form equations are given for the diode efficiency and input impedance as a function of input RF power. Measured and calculated efficiency results are in good agreement. The antenna and circuit design are based on a full-wave electromagnetic simulator. Second harmonic power levels are 21 dB down from the fundamental input power.